Cutting & Sawing, Drilling, Slumping,
& Blowing Out

Rev.  9/1/96 1/18/97 2000-08-04, 2002-07-13; 2003-01-07, -06-19, 2004-12-18,
2005-04-12, -06-26, -11-05, -12-02, 2006-01-22, 2007-03-20, -05-23, -07-02, 2008-02-26,
2009-03-19, -04-10, -09-17, -12-19, 2010-03-15, -09-01, 2011-02-14, -11-20, 2012-07-11. 2013-12-25  

Bottle Cutting
6 Methods
 Rim Smoothing
Neck Stretch
Blowing Out
Turning Out
Other Sites

Cold Working Glass

Huge Site for Bottle Identification

On making bottles historically, here is a site with lots & lots of detailed info and images.
 Glassmaking and Glassmakers Page
And since someone asked me
Bottle Neck Guitar Slider

Back to Sitemap

Bottle Cutting

Sawing Torch Hot Wire Freehand Cut Friction String Burning String
Bottle Cutting Overview
Cutting flat glass is fairly easy.  Glass is usually cut by scribing a distinct scratch with a diamond or carbide tipped tool and then bending the glass along the scribed line, with fingers or pliers or over a dowel or edge and the glass will crack along the line.  Curved lines and circles are normally run (making the crack run along the line) by tapping on the opposite side of the scratch just ahead of the crack proceeding through the glass which can be seen as a silvery surface inside the glass. More

The great problems with cutting bottles are that it is hard to scribe an even, continuous line on the bottle - juggling the cutter and bottle and turning the bottle, the glass of the bottle often varies in thickness, and, if tapping is done, it has to be done inside the bottle to be opposite the scribed line. Possibilities  2005-04-12

To be specific, Sawing will go any way through the bottle (diagonal, vertical or across) and is expensive;  Hot Wire will separate around the bottle very cleanly and is relatively low cost, while Freehand is cheapest but requires practice.

Having decided to do a considerable rewrite of this section, I have changed the order to best results to worse in my limited experiments and tests.  Of course, a good result may cost too much for a particular user.
An e-mail question about not being able to find commercial versions of the wire cutter is correct - other than the commercial wet diamond band saw, there are no commercial/professional versions of any of these.  Bottle cutting is a cheap hobby with limited market.  Glass artists use large lapidary blade saws to cut solid glass or band saws either of which can go for more than $1000.
Laser/Water Jet - I queried firms that make the equipment and I was correct in what I learned from their sites: that laser cutting will not work on bottles due to the size and lack of maneuverability of the head and abrasive water jet cutting will probably not work due to the violence and spreading of the jet inside the bottle although working under water may allow it.
Suddenly I have made considerable progress in testing devices for doing things under this topic.  The goal here is to either run a scribed line by applying stress or not even having to scribe, but breaking the bottle evenly enough that the edge will not further crack and grinding is minimal.
[I am thinking of actually testing some of the more extreme methods mentioned herein, such as wrapping the line with a nichrome wire and heating the wire (a transformer is required); wrapping the line with kerosene or lighter fluid soaked string and lighting the string; filling the bottle up to the line with water and touching the line with a hot bar or poker; filling it with oil and plunging in a hot poker.]
One solution often ignored because of low cost or the size of bottles is to buy or rent a tile cutting saw and carefully saw through the bottle. This may require considerable patience depending on the thickness of the glass. A tile saw may not work on thinner glass bottles if it is too coarse and sets up shattering vibrations.
Also available, but not for rent, are band or wire saws that are designed for wet cutting. This means the metals are protected from corrosion and the motor is up high enough to avoid the water (most wood and metal saws have the motor down low.)  The lower cost ($150-200) versions of these are sold for stained glass work and may not have a large enough throat to take a bottle.  Band and wire saws cut slowly and may break the bottle or the band if pushed faster than the cutting easily occurs.Bottle diagonally cut with band saw
In a recent project, I explored cutting wine bottles with various sawing tools in a worst case scenario of a diagonal cut across the shoulder and neck.  Attempting to hold the bottle in a standard rock saw clamp resulted in the bottle quietly breaking as soon as the strength of the shoulder was cut.  On the other hand, a very large glass cutting band saw with a 1/2" wide diamond blade went through the glass easily in several minutes.  This kind of saw costs $500-2,000 or more. [2012-07-11 Delphi band saws - even larger size may lack clearance for some bottles.] 2007-03-20. [Added note: This casually wine bottle was sawn without detailed care and not finished, so the end of the cut (lower left) has broken free and the top edge is very sharp. The white material inside is powdered glass from the cutting silted in the cutting water.  The original provided to me as a model had been finished in that all sharp edges were rounded and the flat edge somewhat polished.  The whole clear bottle was sand blasted which disguised the partial finish on the cut. 2009-09-17]  An elaborate use of bottles, and perhaps the source of my example, is the transGlass line from Artecnica  which are made in Guatemala in a local enrichment program. 2010-12-01

Hand Sawing - Here is an alternate suggestion that may work for some - note the "(though slow)" though
From: ivantek
Sent: Thursday, March 19, 2009 1:54 AM
Subject: Bottle cutting
I've found another technique for cutting bottles. I found your site, and it was very helpful, but after getting vertical cracks in my bottles from heating and quenching (I know it's not the best method, but I like playing with fire, and figured I might find a technique that worked) I looked for other means of cutting glass.
Long story short, carbide hack saw blades used for cutting tile and cast iron work great (though slow) for cutting bottles. So far I've made a shot glass from a minibar vodka bottle, and a candy dish from a Maker's Mark bottle.
First I wrap masking tape around the part of the bottle I wish to cut, and then draw a line marking the exact spot. The masking tape provides a great surface for marking, and, once you start sawing, it helps keep the blade from sliding off the mark.
To remove the hazard of glass dust, I held the bottles (with a gloved hand) in my kitchen sink with a small stream of water pouring on the bottle. It helps to have a brick or a piece of Tupperware for the bottle to sit on; this gives you more room to saw.
I'm still trying stuff out, but on my last on I found it was easier to saw through a little bit of it, then move to another part instead of sawing through it like a log. Like a piece of wood, the bottle wants to bend if you cut too deep; this can cause it to crack prematurely.
Instead I leave little pillars to keep structure intact, then gently saw through the remaining bits. They usually break, but it's more controlled and leaves less area to sand dull.
Again, I really appreciate your section on bottle cutting and I hope I can contribute to it.
I haven't tried using carbide blades on a Sawzall, but it's something worth considering.
Thank you, and have a nice day,
Ian Hales
---- Mike Firth <> wrote:
Excellent solution to trying to cut through - by avoiding cutting on the weak sides you avoid setting up the vibrations and doing the bending that cracks the glass. Effectively what you are doing is make the cut go through very thick glass - along the line of your cut the glass is a half to over an inch along the blade instead of the 1/16th more or less going straight into the side.
If you do the Sawzall, you will have to be very careful to not go to far and I would suggest fixing the saw and bringing the bottle to the blade. I have used my reciprocating saw in some odd ways and the fact that the tip is free to swing from side to side can really mess things up. You may wish to make a jig with the saw blade edge up and the tip in a slot in a piece of wood so you can bring the bottle down on it.
Also, eye protection will be vital.

Almost every mention of bottle cutting includes a reference to using a hot wire to crack the glass, usually with very few details.  Usually mentioned are a low voltage power supply and nichrome wire, sometimes with a reference to foam cutters.  The simple facts are that the wire has got to be used like the string (above) to stress the glass and either run the crack along the score or crack the glass locally without a score.  The wire must wrap the bottle to stress it all at once because glass cracks are notorious for wandering off to the side, ruining the even edge.  This is quite unlike a foam cutter which uses a wire under tension to make progressive cuts like a hack, band, or coping saw blade.

The low voltage power supply is possible, a fairly heavy battery like a car battery probably being required, as a couple of flashlight batteries, as used in miniature scenery cutters, will not last long with a longer wire.  The low voltage supply ideally should be adjustable but it does not have to be DC so a household doorbell transformer, if of enough wattage would work.  An ideal tool is a Variac, a variable transformer with a dial.   Many variable voltage power supplies sold for electronics work may not have enough amperage.

The problem as I see it is that the wire must wrap around the bottle, bottles come in different sizes so the wrap must also, nichrome wire becomes stiff and brittle when heated, and if an even break is to occur, the wrap must pass close to itself, possibly creating a short circuit across a fairly high amperage supply.

My answer is to take a longish piece of wire, several times the length needed to go around the bottle, so if a short occurs the extra length will cushion the short.  One end of the wire should be fastened on a the end of a rod or board, making the loop immediately, then the rest of the wire goes along the rod to an adjustable point making a d or p shape.  The electrical connections are at the ends of the wire.  For testing a variable power supply and a heavy switch to apply the current suddenly will be used.  Based on my nichrome experience, it may be necessary to have two loops, one for wine and soda bottles and another for gallon jugs because of the stiffness of the wire once heated. 2005-04-12

So, I have finally, 2005-11-09, built and run the design shown in the pictures below, which mostly follows the model described above. [Push F11 in Internet Explorer for a larger window.] A wooden board has porcelain fence insulators screwed to each end (A).  Ceramic fiber board  covers the top of the board (blanket could be used) glued with water glass.  A wire is twisted around one insulator and ends formed into a hook. On this hook is placed a 3" medium weight spring that will stretch to about twice its length (E).  Kanthal A-1 wire is looped at the end and hooked on the other end of the spring (E).  At the other end of the board, the wire is pulled past the insulator and between two washers mounted on a bolt with a wing nut for tightening two washers (A).  Using a bottle for size, the wire is looped around at the cutting point and pulled firmly to stretch the spring and clamped with the wing nut and washers (A).  Alligator clips are used to make the connection to the wire in a flexible way (A, E).  The measured resistance for the wire I am using is 5 ohms.  From previous tests, I found it took about 5 amps to get the wire to a low red heat, so I would need 25 volts.  My Variac is rated to 7.5 amps and fused at that.  [2010-11-03 I am trying to assemble a "kit" for people to use - a test run today showed the wire being 28" long measured 4.2 Ohms and 26 VAC for red heat which computes to just over 6 amps and 157 watts and 24 gauge wire. I will try 24 VDC, etc.]
To operate, I preset the Variac a bit lower with the power off, twisted the bottle into the loop and adjusted the loop to go squarely around the bottle and to pass itself as close as possible without touching, about 1/32" (or 1mm).(B)  In my tests, I switched on the power and edged the voltage up.  When the wire was glowing a dull red, the glass would snap off - I put a drop of water on the glass if I thought I had waited long enough (B).  I also had the bottle snap on its own when the power was turned off on cooling.
The result was a clean break with a slight peak where the wires pass (B).  This without scribing the bottle.  The Coke bottle (further down) would be very difficult to cut by most other methods (not the saw).

Hot wire rig to cut bottles

The pictures of the Coke bottle inadvertently show why the break nearer the neck is not even.  As the wire heats it gets longer.  The spring should take up slack and keep the wire on the bottle, but did not in this case.  I was taking pictures of the loosened wire (C, E above) and the bottle (A below), and did not notice that the bottle was no longer square (A) or did not think it mattered because the wire seemed evenly looped on the bottle.  The neck snapped off, but with a long sharp point (C, D).  A few minutes later, I set up on the ribs below the label.  This time the bottle stayed square, the wire tight (I braced the bottle) and the break was clean (B, D below).  The wire softens in use and on cooling retains the shape of the ribs (D above)

Coke bottle cut in 3 pieces and in cutting rig

The Sprite bottle sequence shows steps in a clean run.  In B, the bottle is position to be twisted into the loop and the wire adjusted closely, square, and in the right position on the bottle (C).  This bottle was the second I snapped for pictures and in A it can be seen tilted, but resting for the snap.  A weight was positioned after the picture was taken because the bottle kept shifting under tension of the wire.  For the third bottle (the clear one above) I decided the block should both prop it up level and block it from rolling.  I used a handy lead ingot. E below shows the bottle just after snapping with the wire still in place and D shows the edges.  Careful examination of the break will show that it not perfectly flat and I will say that the edges are generally very sharp - it should be ground on a piece of emery paper on flat glass or another grinding surface.  But this is the best result of the various methods worked here. 2005-11-19

Sprite bottle showing cutting method

Conclusions Having a heavy duty variable power supply, at least 5 amps, is certainly handy. Variacs of this capacity are often available used for much less than the current $65 retail price.  If a car battery of 12 volts is used, then the wire has to be selected to get to red heat on 12 volts, which means thicker wire of lower resistance. Two car batteries in series, totaling 24 volts or a 24 volt truck battery might be a choice.  One source of thin wire is the coil of replacement wire for the foam cutter mentioned above, sold in hobby and some hardware stores.   Using a household dimmer for wattage control will require more care in handling, because it is actually producing spikes of voltage much higher than the average needed for the amperage.

Followup: In the spring of 2007, I became involved in a project to cut across the neck and shoulder of wine bottles at a sharp angle. [Conclusion: use a glass cutting band saw as wire and lapidary saw did not work.]  I rebuilt the wire cutter for possible production use.


Bottle cutter wire arm revised. The left end of the wooden bar fixed above was cut, shaped and drilled for a wooden pin to hinge the last 8 inches as shown.  The wood pin hinge was expected to be tighter and keep the bar aligned better than a steel hardware hinge of small size. It worked well.  Power was supplied via alligator clips as shown, but they were moved in so that the ends of the wire did not get heated, which made fastening the cutting part of the wire easier. A foot switch was made from a heavy duty push switch mounted in an outlet box.  Ceramic fiber board scraps were used to make a level surface to lay the bottle on.  When tapered beer bottles were worked other scrap pieces supported the bottle at level.
 [All images may be seen larger by clicking on them.]
Wine bottle positioned for hot wire cutting An overall view of a bottle in position shows the added ceramic fiber board so the bottle lays level resting on added structure below the wire bar used alone above.  Note that in this picture the wire does NOT properly wrap around the bottle.  As mentioned above, the wire is longer than needed to wrap the bottle so that if it touches at the crossover point, it will not dead short the supply.
Wine bottle being cut with hot wire The hot wire being applied to the bottle.  The path of the wire is somewhat distorted by the varying thickness of the bottle.  Positioning the bottle and wire is critical to a clean cut.  The wire has to run across the bottle and since it will stretch, tension must be maintained and it will move on the bottle.  When doing these, I had my left hand on the pivoted part of the arm for tension, my right hand* on the neck of the bottle and one foot on the switch. The bottle was yawed to bring the wires almost in touch but not quite. When heat was applied, if the wire moved on the bottle, I released the switch and adjusted. 

The bottle normally breaks on the cool down, so judgment must be used as to how long to apply power.  I counted seconds and did a bit of trial and error - 30-35 seconds for this rig.  If desired, a drop of water guarantees a break if ready.  If no break, let the bottle cool briefly.

*and the middle hand for the camera?   2007-05-23


Bottle Cutting with Torch

Cutting glass with a fine tipped torch is old news having been used in the automated glassware industry for decades and by certain art glass goblet makers.  The problem for most of us is the very small hot flame and turning the bottle.  One choice is discussed below.  I was told of a goblet maker who sheared his by setting them on an old record turntable. I recently received a phone call from a guy (who promised photos) who said he used the miniature oxy-butane torch that uses tiny tanks that look like the CO2 cartridges used in seltzer dispensers and he spin his bottles by tying a yoke on the neck so it hangs straight and twisting the hanging long cord so it spins for a while.  As with hot wire, the glass may crack on cooling rather than heating. 2009-09-17

Turning rig to cut bottles with oxy-acet torch flameI took various parts I had around and combined them into a rotating bottle holder and "cut" a couple of bottles with a fine tip welding torch - worked good with and without scoring.  Following comments on CraftWeb about using a record turntable, a carbide scratcher and a very small torch, I headed for the garage.
I found the Lazy Susan swivel built for drilling my rod optics and a 3" piece of 4" conduit welded to a plate with a center hole made for use as a punty mount.  I drilled the swivel in the center to take a bolt through the center of the holder, with a clearance hole below for access to the nut and counter sinking the bolt head for a level surface inside the holder.  I tapped three holes at the 1/3 points about 2" up and installed short 1/4" machine screws.  Originally I cut 3 wood blocks to hold the bottle, but they were too thick at 3/4", so I cut a 3" section of 3" PVC and divided it into thirds.  I had to further trim the PVC sections to fit around the bottle.  Adjusting the 3 screws centered the bottle on the turntable.  The turntable is less than perfect, it turns but with a bit of a hitch at one point.  After running tests, it dawned on me that I could use a socket on the nut underneath and turn it with an electric screw driver or drill.
I put the 00 welding top on my Oxy-Acetylene torch and turned the gas pressure down.  Bracing the torch against the table, I started turning the bottle by hand and pivoted the torch in to play on the bottle.  After a few turns, the bottle snapped on the the line of the torch.  I tried a couple of more bottles, cutting at more than one point with the following results.

  • The top of a Coke bottle disintegrated when the turntable hung up briefly (right)
  • A bottle scratched all the way around had a crack that wandered up and down. (not shown)
  • A bottle unscratched produced a lovely even crack while heating.
  • A bottle unscratched was heated for longer than average without cracking but cracked perfectly when the torch was removed. (This also happens with hot wire sometimes.)

Even the best cuts require smoothing and polishing as described at the end of Freehand.


All you need is a wooden V, a glass cutter and a 1/4" steel rod bent at the end with a rubber ball shoved down on it. (below) And then practice, practice, practice!!!
 Most commercial bottle cutters are junk that endures a fad of heavy advertising on television every few years. Typical price is $29.99 for something worth about 4 bucks and it still takes practice and skill to work.  I will offer one small exception to this statement as there is now (2003-01) a unit that looks like it might work better - it has three rubber wheels and a cutter wheel mounted in the corners of the bottom of an L-shaped platform, the upright keeping the bottle aligned, so pushing down centers the bottle and pushes on the cutter one shown here: bottle cutters - bottle cutting kit - stained glass supplies - tools

Here are previous notes.
Book: 101 Projects for Bottle Cutters, Fischman, 748.2 F5290 Dallas
Pub.Lib Downtown
Good basic reference for methods, shows about half a dozen cutting methods/jigs and about the same for breaking, including ice, fire, nichrome and tapping inside. Projects not reviewed 3/13/95  In August 2003, I ran into this book again and took a look at the projects.  They are absurd.  Most result in something that looks just like a bottle with a chunk missing.  Several call for cutting into the side of a bottle which isn't really covered in the cutting area.  One project is cutting the bottom off a bottle to make a coaster for a glass.  Another involves cutting the bottom and neck off the center, gluing the bottom to the neck to make a door handle, glued to a spindle (the middle can be a lamp chimney in another project.) Sad.

The tools needed are a simple glass cutter used for flat glass, a trough to hold the bottle, and a rod to tap the score around the bottle. These are described in the process description below.

Image of Bottle cutter made of 1x4 wood.The proper way to cut bottles is to use a glass cutter (like for window glass, cheap at the hardware store), placing the bottle in a V-shaped trough (Two pieces of wood nailed at edge with another to act as stop for the foot.) Add a brace or hold the edge at the correct point so the cutter is held fixed (it helps if the wood is wide enough so the hand can rest on the wood, say 1x4" wood for ordinary bottles) and the bottle rotated underneath it. Do not go over the score repeatedly, do it once and don't waste time after scoring the bottle, it becomes harder if you wait - it "heals".

Bottle rapping rod, shown outside and inside bottle.After scoring the bottle, a metal rod bent at the end is inserted in the upright bottle and the glass is tapped, starting a crack, which can be seen as a silvery surface in the glass, and worked around the line on the bottle. The rod is most effective if it is heavy enough (3/16" or 1/4") to have its own momentum and if a rubber or wooden ball is drilled and mounted on the rod, then adjusted to rest on the neck so the bent end hits the same point down in the bottle every time. The bent end should be very short (especially for cutting wine bottles with small necks) and the tip should be sharpened to a blunt point for precision. With a stiff rod, it may be necessary to bend the tip long (1") to be able to bend it then saw it off short (3/8") and point it with a file. The middle of the rod may have to be bent to reach the wall of the bottle in bottles with long narrow necks and steep shoulders. Check this before scoring the bottle (shown straight in drawing, would have to bent to get near shoulder.
If cutting a large diameter bottle (demijohn, gallon jug) it should be good to not bend the end to 90 but choose a somewhat more open angle so the end is at 90 to the glass at strike so all the weight it just behind the tip.  2008-02-26
  Practice with other bottles if trying to cut something in limited supply. No matter how good you get, some bottles will be lost as cracks run astray. This was never as easy as the TV ads for the bottle cutting gimmick (no longer sold) tried to portray.
First sent as MF Reply 11/6/95 8:25 AM
  When finished cutting the bottle, the edge is very sharp.  The easiest way to treat the edge is to simply hand grind the edges.  This can be done with the kind of sharpening stones used on pocket knives and chisels, where each of several grits will cost $5-10.   An alternative is a wooden dowel or a chunk of a broom stick, wrapped with black emery cloth 'sandpaper' where several sizes of grits will cost about $1-2 each.  Use the coarsest grit in each case to knock down the corner of the edges, rounding it if you wish.  Repeat with finer grits, taking out the roughness left from previous grits. 2003-02-04

Cut apart bottle on bench with gapThis shows an alternative way of attacking a bottle. The bottle was cut by laying it in the open gap between two 2x6 boards in an outdoor bench. The hand was rested on the board in front, holding the cutter and the bottle was rotated with the other hand. This gives good support for the hand, but the larger V is needed with a bottle bigger than this, in my opinion, or a board needs to be set under the hand to raise it up. When cutting the bottle lengthwise, it is held with one hand and the cutter used pushing straight down. This picture can serve as warning because I cut myself rather deeply on the finger. I had left the neck laying in the groove and was cutting the long line when the cutter slipped off the glass and I banged my finger on the very sharp edge of the neck, putting a cut about 1.5" long perhaps to the bone, but in line with the tendons and muscles, so a strong bandage replaced several times a day and it is healing. The damage you see to the bottle was from trying a medium head torch on the scribe lines to break the glass - not very successful as breaks occurred in long curves in addition to following the neck. 2002-02-07

Bowl shape fused from cut apart bottleThis is a (failed though interesting) attempt to take apart a bottle and make a bowl in one step. Originally the bowl was to be donated to the Empty Bowls so the label material - which I can't test for lead - was put on the outside. Obviously the bottle was a Corona beer (inset) and I chose it because it was 1) Laying on my front yard where it shouldn't be and 2) it had light thin clear glass. The bottle was first cut around the neck and tapped on the outside to run the crack, leaving a piece like the neck in the picture above. Then the base was cut off around the side and tapped from the inside (more efficient, less force required.) Then the cylinder of the body was scored up the sides and tapped inside to break it into front and back. The back was scored inside (also easier) and divided in half. The bottle neck was then cut apart into pieces. and the whole arranged in a bowl mold for fusing The problem was that while the side pieces sagged and fused nicely into place, the small pieces from the neck, instead of filling the gap, fell or folded down into the bowl, leaving an open gap in the bowl shape. The inset shows the bottom of the bowl (click to enlarge image) If the bottle was screen printed hot, the label will normally survive fusing. This one was also run through the dishwasher to test it. 2002-02-07

Burning String - I used several soda bottles that I had collected for fusing and tried several variations.  I did not find the results satisfactory, but they may be in some cases, so read on.2004-12-18
I came across two videos showing the use of acetone (nail polish remover) that produced better results than shown here. In each case they tie cotton string on the bottle, remove the string and soak it in a small container of acetone, replace the string, light it and turn the horizontal bottle on its long axis while the flame burns with no smoke, then plunge the bottle into water to snap it. In both videos only a very brief view of the edge is shown but it appears that both have rough spots. Beer bottle  Wine  good captions 2010-03-28
In a further variation which I have encountered several times just recently but not tried, again the string is tied tightly around the bottle and removed, but this time soaked in lighter fluid in a small bowl before being returned to the bottle and lighted from the bottom with the bottle horizontal so the flame climbs up and around. When a crack is heard cold water is dribbled on. Appears to be a cleaner break and no soot. I have no lighter fluid to test. 2013-12-25  
Thin walled bottle "cut" with burning string.My first tests were on even walled (Sunkist orange soda) bottles, where I scribed a line, wetted a string in denatured alcohol, tied it in place and lit it.  The alcohol evaporated and burned so quickly as to provide no heat to the glass.  I was also frustrated that the string I knew to be cotton was too thin and new string I had bought turned out to be nylon or polyester in spite of not being marked.
I bought a heavier cotton string at the grocery store.  I switched to kerosene because of its slow evaporation rate.  On scribed bottles, with two wraps of string placed just below and touching the scribed line and the bottle standing upright, the flame produced a distinctly audible crack at about the end of burning time.  It also produced a black sooty surface.  Unfortunately, the crack followed the scribe halfway around the bottle and then continued 1/4" higher for the other half.  Worse, there was a errant heat crack that curved about 1/2" below the scribe.  So the bottle was cut, but a lot of grinding would be required to produce an even rim.   Several additional tests were run with essentially the same result.  [In the image, the scribe line is just barely visible against the soot about 1/4" below the back rim.  Note the dip in the rim cut at the front above the lower bulge of the S.  The white visible inside the bottle is the background for the blue lettering on the other side of the bottle.
Then it occurred to me that the flame would stay along the string if I laid the bottle on its side, propped on a fire brick so the burn line was out in the air.   This produced less soot and a more controlled flame and with the scribed line, cracked free, but the crack varied above and below the scribe by 1/8th inch or more and branch heat cracks showed up.
Thick walled Coke bottles "cut" with burning string.I decided to try some tests with just the burning string, no scribe.  This seemed to give results that were as good (or bad) as previously on the even walled bottles.   I pulled out a couple of old classic Coke bottles.  Here scribing the line is a real problem.  Above the label the bottle is curved, making scribing on the sloping shoulder difficult for me.  Below the label, the bottle is ribbed making for an uneven surface backed by uneven thickness.   Almost any crack around the bottle would improve on what I have gotten in the past.
After I wrapped the string soak in kerosene, tied it with an overhand knot, arranged the ends nicely along the other strands, lit the fuel and stood and watched.  And watched.  And watched.  The flame went out and the bottle didn't break.  I got a small scoop of water and touched the drip to the string - ta ta!!  Nice crack.  It wandered as much as the scribed bottles without the scribe hassle.  I took off the bottom of the same bottle (around the ribs) and worked a couple of other bottles, getting the same results.  Bottle cut twice with burning string showing soot
So, a burning string works to cut a bottle if 1) a medium heavy smooth cotton string is used; 2) with kerosene, not alcohol; 3) with the bottle on its side;  4) with the ends carefully tucked in; 5) and a large drop of water is applied to the string as soon as the fire is out;
IF an edge is OK that varies up and down by a good fraction of an inch and will have to be ground down a bunch to make a drinking glass or goblet AND the loss of 1 in 3 or 1 in 4 due to branch crack (which keeps running when grinding is done.) [2005-11-19 After doing the wire snapping below and seeing how even a small deviation from square can lead to a big point, I think a better choice on the string would be to use finer string and go around twice with the knot running under both strings so its width is a smaller proportion of the burning line.]

HI there, love the website, just thought I'd add my way:
My brother and I started cutting old 2 liter ( I think ) glass bottles when we were around 12 or so, and we didn't use fire, and had no access to batteries. What we did have were spools of mason line (the kind thaT brick layers use, it's usually in yellow or day glow pink) from my fathers construction tool bag.
We would tie one end to a hook in a wall, or even a door knob. The string was played out about 2 feet or so, and the other end was tied to our belt buckle. making the string wind once around the bottle, we would put some pressure with our bodies away from the wall, and run the bottle back and forth along the string, usually getting the string hot enough that it would melt. Immediately after the string broke, we would dunk the bottle into cold water, and the bottle would split neatly in half (or wherever the string was).
Possible problems with this technique:
1. you get tired before the string is hot enough
2. the string breaks before adequate heat is generated
3. the point at which the string crosses itself leaves a little dip or rise
in the bottle
4. The string moves along the bottle as you move it back and forth

To address # 2 if only moderate pressure is applied to the bottle, there is better chance of getting the bottle hot before it breaks. There is also some brands of mason line that will last longer than others, but I have never figured out which.
To address #3 if as you move the bottle back and forth you give the bottle a slight roll, so that the cross point of the string is moving, it will eliminate the little dip.
To address #4 if I put a layer of tape (masking, scotch, whatever) where the string will be, the string will cut quite easily through the tape, leaving a guide for itself, and making it easy to keep in place.

As I said, My brother make many bottles this way, and had none of them shatter. the only things that can go wrong are that little dip in the cut surface, and simply not having the bottle break in two, which just means that you have to do it again.

Anyway, good luck making bottles,
Adrian S. Moreno
San Ysidro, California.


Bottle Neck Guitar Slider  I was contacted by someone in the UK to make a guitar slider from a wine bottle neck and after looking on the Internet decided the effort in international mailing since a place in the UK makes them in different styles.  But I wandered to a discussion here from 6-8 years back and thought some of it was worth borrowing.
  Guitar sliders require tuning the guitar to an open chord (so it sounds a chord when strummed) and then a hard object (because using the finger across all the strings gets painful) is slid along to make other chords.  The Hawaiian steel guitar is played flat with a steel slider, but the slider can be a piece of steel or brass held edgewise between two fingers or a tube slipped over a finger.  The tube can also be glass, which is why there is a section here, and the traditional is a piece of wine bottle neck for the thicker glass.
Note that getting the neck off the bottle, however scored, is easier than cutting the bottle, since leverage will snap the neck.

posted 12-13-2002 06:43 Edit/Delete Message Reply w/Quote I thought that I share my slide making experiences. I read through just about everything that I could find on the topic of bottle cutting. I haven't tried the special cutting blades or saws.
The only procedure that consistently gave me relatively clean breaks was the following. Safety glasses and leather gloves are probably not a bad idea though I've never had any bad experiences with the procedure below.
1. Draw a line around the bottle neck with a magic marker.
2. Score around the line (only once) with the edge of a triangular file . Using a triangular file allows you to press down firmly with your thumb directly over the scoring edge of the file thus creating a score of more consistent depth. It is important to score only once and try to make a score line of consistent depth otherwise the bottle breaks unevenly. I practiced on beer bottles first to get the feel of the procedure and then moved to thicker glass.
3. Heat the score in a candle flame while rotating the bottle. Soot is deposited where the flame touches the bottle so you know you are hitting the score line evenly.
4. While hot, rotate the hot score under some cold running water. Usually, it breaks cleanly. Most times, you can essentially pull the neck off the bottle. No tapping, smashing, etc. to potentially send glass shards flying around the room. [Glass shards on the kitchen counter/floor makes my wife angrier than practicing the same song for hours on end while enjoying the tone of my newly cut slide.]
5. If neck doesn't break the first time, then dry the bottle, reheat the score and cool it again. The thicker glass usually required two heating/cooling operations.
6. Then file and sand smooth.
posted 12-14-2002 15:26 Files come in a variety shapes and sizes (round, flat, triangular, needle, etc). The triangular file that I am referring to essentially describes the shape you would see if you looked at a cross section (cut it in half and sighted down the end). I should add that you should use one of reasonable size since I broke a smaller one recently.
The reason that I chose this type of file is two fold. One for leverage and two because my instructor in a laboratory glass blowing short course demonstrated that this type of file was very efficient for scoring and breaking glass tubing. For tubing, one just needs to make a score about one third of the way around the tube to break it cleanly. Interestingly, if you score a glass tube all the way around the tube it doesn't break cleanly perhaps due to uneven stresses introduced into the relatively thin walled glass.

an McWee From: Worcestershire, England
posted 12-02-2003 02:33 After many years of refining the ancient art of bottleneck making (and it now being a thriving business for us!), all the above methods listed work for each individual who chooses to make their very own, personal bottleneck. We found that a lot of the problems relating to the straight separation of neck from bottle occurred at the main score-line, opposite to the point of contact with whatever you use to break the neck off. We found that if you rest the score line directly on top of a sharp edged, right-angled piece of metal, with the score line parallel to the top of the angle and resting into the groove, much of the stress factor on the line was relieved.....and if i knew how to draw a diagram on here - i'd gladly show you! Hope that all helps, if not - feel free to contact me off our web-site at 

 posted 01-22-2004 04:09 Edit/Delete Message Reply w/Quote Who'd have thought that this would continue over 3 years. An interesting topic.
I used my trusty glass cutter, whose cutting wheel is supplied with cutting oil - a mixture of 3 in 1 oil and turps. if you dont have such a beast just dip your cutter in white spirit.
I found it impossible to run a continuous cut all around the neck, but used a series of small say one inch scores. - on no account double up over a score, do it once only. Best use a piece of masking tape with a mark showing your start/finishing point.
Once the perimeter is scored you have to tap around the score with the other end of the cutter.
Good taps but not so you would expect to "smash"the end off in one go.
Keep tapping all around and a crack will appear - keep tapping and chasing the crack around and off it comes.
I did 2 bottles in minutes - even took the annoying lip off the cork end (about 1/4 of an inch) using the same technique.

posted 01-22-2004 20:32 A tile wet saw.
I've got one because I am a tile and stone contractor so I thought before I give this sage advice I'll go out to the garage and try a couple. Worked 6 out of 7 times clean as a whistle. The one that failed was a thin beer bottle neck that you wouldn't use for slide anyway but the three thickest ones were the easiest and cleanest. Now some of you are probably saying that that's all well and good but you don't have a wet saw. Well every Home Depot does. It's at the end of the tile aisle and it's for weekend warriors to get their more complex cuts done. The one near me lets all the homeowner Joe's make their own cuts so that situation would be easy but if the one near you has the staff do it just slip 'em a 5 spot and off you go. Or have your wife ask 'em that always works. Either way you might have to buy $3 worth of tile put some marks on 'em and pretend you need some cuts done and slip the bottle in at the end. This will work. Home Depot people do not care about things like this.
Water jets and a fast spinning diamond wheel. It's a beautiful thing.

 posted 11-30-2000 19:32  I recently made 2 new slides from wine bottles.  I found 2 wine bottles with real straight necks and small openings and cut them using a carbide hacksaw blade. Then polished them with sandpaper--100-400 grit. I held the bottle by laying it on the kitchen counter on a bath towel, with the towel folded thicker on one end to support the neck of the bottle. It worked well, but had to rest the hands several times in the process! The string and ice water method I tried as well, but this left too jagged a cut requiring too much sanding.

edroperFrom: Seneca Falls, NY
posted 02-09-2004 10:35  I just cut my first bottle neck using the carbide rod saw, belt sander, sand paper method. I double cut it and it turned out great. The bottle is from Goose Watch "Finale" white port made by Swedish Hill Vinyards here in the Finger Lakes. The neck is almost perfectly straight, thick glass, fits my pinky perfectly, and is a real nice green/brown color. Oh yeah, I like the tone a whole lot better than the brass slide I've been using.

 posted 02-22-2004 18:11  Thought I'd get busy in the workshop and rustle myself up a few new slides beofre I wasted all those good bottles at the recycling centre. Found a great Virgin Olive Oil bottle with a 4.5inch straight section. Taped it and cut it with a carbide tipped saw in a matter of minutes and then spent a good 15 to 20 minutes with a variety of sanders to get it just perfect. I had a little skip in my step as I headed back to my guitar. A little too much skip. Caught my foot on a cable and smash. Oh well, there's plenty more bottles where that one came from.



#: 126130 S5/Glasswork
01-Oct-95 04:18:03 B: #125764-Cutting Glass Bottles Fm: Gerry
Phibbs/CA[Staff] 76556,624 To: Lynn C. Russ 75327,1237 (X)
Hi Lynn..
It's not a difficult thing to do, but as with most things, it can require some practice to do well.
Bottle glass is typically very soft, and can be cut fairly easily, but remember that the bottle glass is also of uneven thickness, and that can create some problems. Also, with many bottles used for many things, there's a "relief" at the bottom, or in the bottom, to allow the bottom to break out if too much pressure is exerted inside the bottle. Be careful around this little "relief" which will look like a dent in the glass, it's the weakest point on the bottle.
Peace -Gerry

Even further comments:
Once the bottle has been scored, there have historically been a number of methods for cracking the glass, most of which are messy, some dangerous.
Included are wrapping the line with a nichrome wire and heating the wire (a transformer is required); wrapping the line with kerosene or lighter fluid soaked string and lighting the string; filling the bottle up to the line with water and touching the line with a hot bar or poker; filling it with oil and plunging in a hot poker. Some of these latter ones may work without scoring the line, but probably shatter the glass above the line, leaving pieces of glass to cut people.

Subject: Re: Bottle Cutter? From: (Douglas
Wiggins) Date: Thu, 29 May 1997 15:08:04 GMT
>>Remember the 60's? Looking for way to cut bottles--or at least neck.
>>Does anyone sell a bottle cutter in the 90's? Or is there another way to
I have one of those old bottle cutters, and it is a simple device which involves a simple wheel-type glass scoring tool, mounted on a jig which allows it to scribe a score around the circumference of a bottle (it uses wing-nut-fastened adjustments to let it be set for different diameters of bottles) - putting a bottle sideways into a partially open drawer and turning it while holding a glass cutter on it would probably work nearly as well. Once the bottle is scored, there were a couple of different heavy-gauge wire tools, bent in such a way as to make a crude hammer at each end of the wire (bent so that a rounded edge hit the glass), and a little gadget was attached to the wire to hold it in the neck of the bottle (there were two such wires, with one being for small necks and one for large - the large one just used a three-inch-square piece of fiberboard, held at an angle so that one of the "points" of the square went down inside the neck), and the wire was then tapped along the inside of the bottle, moving around it, until it broke. The idea was to start with a slight tap, and increase the strength until it started to crack, possibly hunting around the bottle until a place was found where it would start to crack.
It took a bit of practice, but, once one got the hang of it, it was possible to cut bottles cleanly nearly every time.

3/14/98 In article <>, Suz  writes:
>reading your post about the coke etc bottles. I must say it came out
>nicely! Now, if I could just figure out a way to cut rings out of a
>bottle without breaking 3/4 of it! The two rings I have took me a
>twelve-pack! Is there a better way? btw: i had purchased the "bottle
>cutter" from Glass Crafters, and it is rather a hit & miss affair. It's
>plastic, and tends to slide around, and I believe the cutting wheel is
>rather cheap. Any ideas? -suz-
A. Cut the bottles at least 24 hours after finishing the 12 pack :-)
B. Open the bottle by cutting as far away from the rings as possible (see below)
C. Skip using any "bottle cutter" and make your own much stronger rig.
I cut my bottles (remember the outside of Coke bottles is uneven, ridged, etc. compared to most other bottles) by first making a wooden trough to hold the bottle while I turned it. Basically I chose two pieces of scrap wood, one for the base and another just wide enough to place the cutting hand in a good position with respect to the bottle - I think I used 1x3 and screwed it to the edge of the base.
Also on the base I put a piece of wood scrap about 3/4" thick just far enough from the upright to keep the bottle in place and another small piece to position the bottom of the bottle.
I used a perfectly standard (cheap) hardware store glass cutter. Because of what I wanted to do, I made my first cut near the base of the bottle as I recall, although I did a few up on the bulge at the base of the neck. Turning the bottle in the trough with one hand, I held the cutter in position with the other to pivot against the glass.
To run the score, I made my own inside breaker by using 1/4" steel rod. I bent about an inch of the end to a sharp L in a vise and then cut off most of the inch until the short leg would fit inside the neck of the bottle. I then filed the short leg to a blunt point. Depending on the bottle, I then bent the long part of the rod to fit the pointer under the shoulder of the bottle if I needed. As I recall, I couldn't find any wooden or rubber balls so I roughly shaped a scrap of wood to a ball end, drilled it undersized and pushed it on the rod to act as a pivot for the rapper.
Once I scored the line around the bottle, I rapped the crack around it and took the bottle into two pieces. What happened next depended on what parts of the design I wanted to use. If necessary, I ringed the bottle again and rapped it apart. I found that whether I used the neck rapper from the neck or the ball rapper on the cutter depended on how the bottle seemed to be most attackable.
Since you want to make rings, I would suggest taking the bottom off then scoring above and below your rings and tapping with the ball through the bigger bottom opening (use gloves or something to keep from cutting yourself on the sharp bottom edge. If you felt more comfortable, you could take an abrasive stone to the newly cut edge.) I usually wanted pieces of the pattern running up and down the bottle, so I would lay the bottle section down, reach in through the opened bottom with the cutter (gloves) and pull the cutter from inside toward me. (Doing one or
more different lines before rapping depending on my mood.) I would then rap the inside score from the outside of the bottle, much easier to follow, I found. Of course I ruined a few, but I kept all the pieces to see what I could do with
short fragments of text, parts of logos, etc. Bottle glass is uneven in thickness so it tends to produce "creative" shapes.

Subj: cutting beer bottles
Date: 98-03-15 20:17:40 EST
From: (Stanton, Susie)
To: (MikeFirth)
Hi Mike, gosh thank you for the wonderful post to my question 'is there a better way'. just last night i was having a few beers with a local carpenter/craftsman and we talked about making a cradle so i could turn bottles. bobbalou said he thought he had a pretty good idea of what i want and he will "get right on it". (course, in island time, that could
be anywhere from 3 months to a year. it's a whole 'nother time zone here!) so i decided that i am going to try to make what you have described. but i am having a hard time picturing the thing! i -was- thinking in terms of having an uprighted end, with a half-circle cut out, to rest the base of the bottle on, but then the neck part threw me; is that the scrap 1x3 you meant? also the part for piece 'just wide enough to place the cutting hand on", is that so your hand remains firmly set while you turn the bottle?
boogers! i am sorry to ask you so many questions about this! perhaps i will get down under the house (we are all on 12' stilt/pilings here) and rummage through my "treasure pile", and see what i can come up with. i sure do miss that 1970's bottle cutter they used to make. oh and btw, i also did the "tie cotton string wetted with kerosene around the base, light, let burn, plunge into cold water" and it does work! but the wine bottle cracked a lot up above the break. the bottoms of the wine bottles have that neat "thumb hole" and i am looking forward to seeing what it will turn into! i am not an artist at all, and know it, but i sure do like messing with these things and seeing what they can turn into. thanks again for that great informative post!
St. George Island, FL ~ 65 Miles from the nearest WalMart - thank God!
Make a V of wood - a long trough to lay the bottle down in.
One side should be about the size of the bottle laying on its side.
The other side should be a bit wider so space is handy to nail down a scrap of wood.
It should be longer than the bottle, somewhat.
Lay it so the wider side is on the work surface and the narrower one sticks up.
Lay the bottle in place, letting the neck stick out the end enough to grab it.
Mark the location of the bottom of the bottle so you can nail a scrap of wood there to keep it from moving down the trough.
Move a piece of wood into the side of the bottle on the bottom wood so the
scrap just touches and mark it.
Remove the bottle and nail/screw the two pieces of scrap in place to align the bottle.


Rim Smoothing
How can I get a smooth rim( similar to those on purchased glasses) on the wine bottle I've cut ?
 That rim is called 'fire polished'. Store bought glasses have it done right at the end of the blowing operation when the glass is separated from pipe by using a tiny hot flame and rotating the glass - the tiny blob at one point on the rim is where the last bit lets go. Hand made blown glasses have a fire polished edge because they are shaped hot. The only* (usually impractical) way to do it with bottle glass is to preheat the cut piece to about 1000F and while hot, hit the edge with a torch and then anneal. [but see below*] The torch should be compressed air or oxygen with propane as drawing hot kiln air into an air/propane torch works poorly.  Acetylene does not work well on glass, depositing carbon in the glass and overheating quickly - it is too hot.
The rim is the flaw in making cheap glasses from cutting bottles. Basically you have to smooth it in several steps to a point it is acceptable to your mouth. If done without a belt sander it can be done with a selection of small grinding wheels or by hand. Hand is most easily done by taking some flat glass and using rubber cement to glue down emery paper in a few different grits. Inverting the glass on the surface of the coarsest and adding a little water will quickly level the rim. Then turning the glass at an angle will permit taking the sharp outer edge off. If the process is repeated with finer grits it will get a finer and finer haze on the ground part and less gritty feel. The inside edge can best be done (without small grinding and buffing wheels) by cutting emery cloth into 1" strips and making a shape like a small hacksaw from 3/4-1" wood so the emery cloth can be applied flexibly across the edge. Again coarser grits will take the sharp edge off and a succession of finer grits will smooth it. 2007-07-02, 2009-04-10
sanding blocks and paper tearing tool
The image shows a hacksaw blade mounted to a board (which is cut to fit diagonally in a tray holding full sheets of sandpaper) that allows tearing off narrow strips. Small washers under the blade leave a gap for the paper. The two handles below the blade are used to tension the narrow strips inside the curve so that the abrasive can work the inside edge and round it.  Several grades of emery (black) paper are needed to first shape the edge then smooth it to take off roughness.  For ultimate smoothness and polish, a polishing drum in a Dremel type tool may be needed. 2007-08-15
Bottle cup showing torch edge heat effect * When I used a fine point torch to cut bottles on a turntable, I was startled to see the lack of cracking at least in fairly thin soda and beer bottles I used for testing.  When asked in an e-mail about heating edges for smoothing I first suggested building an open top mini-kiln with a turntable so the cup could be preheated and set in, turned automatically without the overwhelming heat and volume of the kiln/annealer, with the rim above the edge of the mini-kiln while the element keeps the glass warm.  After hitting with a hot torch, the cup is quickly returned to annealer.   Then I had a second thought and felt that a test of the turntable and torch without the mini-kiln might be worth it to see if quick lifting out and return with padded tongs, trusting the thin glass to have low enough tension to survive.  I would put a frax board or pad on the table to keep it from chilling the thicker base, especially without the preheating that would occur in the mini-kiln.  2009-04-10
(The image shows glasses clearly cut with a torch because the etched frost on the bottle has been melted clear around the edge.)


For pictures of drill bits and techniques, go to coldwork.htm#DRILLING
Drilling can be done with specialized drills, or grinders, or ....

----- Original Message -----
From: melanie hubler
To: mikefirth
Sent: Saturday, June 25, 2005 9:41 PM
Subject: glass wine bottles
Hello Mike,
My grandaughter and I have a whole bunch of wine bottles and are interested in drilling holes in the side of them so we can put Christmas lights into the bottle. The holes need to be about the the size of a nickel or a quarter. We are not completely sure if we understand what to do and how to go about the drilling. We tried to use a Dremel tool with a small diamond tip ( we think it was diamond) and it was glowing and sparking...and the bottle cracked. So we don't really know what to do. Please help us!!!
Thanks so much,
Melanie and Ashley

The most basic rule of drilling glass is that it must be drilled wet. For a bottle, the easiest solution is to fill the bottle with water and cork it. Then, in any case, surround the site with plastic clay (the stuff kids used to use at school - Plasticine, an oily clay, not Sculpy) that will make a dam for water above the glass. If you are going to do a lot, you can set up a rig to submerge the whole bottle and support it under water.
The size of the hole you want to do is relatively large and will be difficult to do by hand - it is normally done with a drill press or a special shorter tool just for drilling glass (look at If you have or are willing to buy a support rig, then a diamond core drill, which is a cylinder of steel with diamonds embedded in the edge, will make the hole all at once with the fewest problems.
If you wish to do it by hand, then the most reasonable choice is to use a spade type bit (which looks like a spear point) to make a first hole that is not very large (up to about 3/8") and then use a grinder tip on your Dremel to enlarge the hole. With this type bit, having the patience to grind through with the tip without pushing too hard is vital. Once the tip is through so the grinding is on the side, it goes much faster. Wet all the time.
Good luck.
Mike Firth

----- Original Message -----
To: mikefirth
Sent: Wednesday, June 11, 2003 1:25 PM

Hello Mike, I have a great looking wine bottle that I want to turn into a lamp. Can you please tell me how to go about doing this. I know that first I would have to drill a hole in the bottom of the base of the bottle, and then buy a lamp kit to fit the bottle.
Any help from you to do this project the proper way, would be greatly appreciated. Hope to hear from you as soon as possible.
Thank you very much.
Sincerely yours, Edwin A. Johnson, Sr.

Date: Thursday, June 19, 2003 7:55 AM
Actually, it is possible to make a conversion without drilling as there are sockets where the cord comes out the side of the cap and the lamp parts are mounted on a cork that fits in a bottle. We carry them at Elliott's Hardware and I would expect you could find them at craft and stained glass stores.
If you are going to drill the holes without specialized equipment, you can get a spear point glass and ceramics bit at many hardware stores. You will need some clay or putty to make a dam around the hole site to hold water for cooling. You should also cork the bottle and fill it with water so that when you break through, all the water does not drain into the bottle. Drill at moderate speed and be prepared to loose a bottle or two.
The hole will have to be about 3/8" to accommodate the so called 1/8" pipe thread tubing used for assembling lamp parts.
Mike Firth

From: Soper, Mike []
Sent: Sunday, May 04, 2008 5:45 PM
To: mikefirth
Subject: cutting bottles
How would I go about cutting a 2” hole, 2/3rds from the top, in a 1.75 L wine bottle?
The only practical way to quickly make a neat round hole this large is to buy a 2" diamond grit edge core bit and use it in a drill press in a pan of water. A slower way requiring considerable care would be to drill a smaller hole large enough to admit the grinding head on a home machine for edging stained glass and then using the grinding head to enlarge the hole to 2". If you need only one or a few, contacting a mirror & glass company that drills holes for outlets and electrical fittings might be practical.
Is it possible to burn a hole, +/- 2”, in the side of a 1.75L wine bottle with a blow torch or propane torch?
Possible, but only under absurd conditions. The first problem is that if you hit glass with a torch while it is cold, it will shatter. In addition, an ordinary propane or blow torch just barely gets hot enough to soften glass (MAPP gas adds heat for bead making) So to make it possible, you would have to heat the bottle almost the to sagging point in a kiln (about 1150F) then work with it under those conditions with a compressed air/propane or oxy/propane or oxy/acetylene torch to soften a spot at which you would pick a hole then pull glass to the size of the hole then melt the edges to shape and anneal the glass. While a core drill is expensive, this costs more depending on what you have and working at 1100F would require a protective suit like steel workers and fire fighters use.
Lots of great information on your site, however, I did not see anything that would answer my questions.
Thank you for your help,


Link to Bottle Labels
I consider bottle slumping to be one of the really boring activities in the world, but I will share some information about it since everyone who gets anywhere near a kiln seems to be interested in it for a while. The problem from my point of view is that unless one gets really creative, there are only a limited number of things one can do: stretch the bottle, flatten the bottle, make a spoon holder, make an ashtray. [Some people have made societal comment by arranging slumped bottle shapes in ways that suggest comment on mechanical and tired society - "Preacher and Choir", "Exhaustion", but that is more art than slumping, I think, and not me. 2002-07.]

To change the form of a bottle all you need is an oven that can reach about 1400F, which all pottery kilns and most glass annealers can do easily. For the result to survive cooling, either the kiln must lose heat especially slowly or there must be a controller that will take the temperature down slowly. If the bottle is cooled too rapidly, it will shatter from the stresses inside.

If the kiln is tall enough, it is easy to stretch a bottle. More. If the heating elements are in the walls, it not being a good idea to get glass on them (besides the glass will probably shatter from local heating if too close to the element), a wire must be stretched across the top of the kiln from which to hang a loop of wire in the center. The neck of the bottle is fixed in the loop. When the temperature is raised, the bottle slowly stretches as the temperature passes well beyond 1100F. If it watched through a peep hole, when the desired stretch is achieved, the lid is opened, letting the temperature drop to about 1000F and freezing the glass in shape.

If a bottle is laid on its side on a kiln shelf, it can be heated until it slowly sags and the heating can be continued until it is flat or nearly so. Normally the first form the bottle takes is a cylindrical cup - the top sags down pulling in the sides. A cup shape can be used for ash trays (for the few people who still smoke) or a spoon holder. For a more predictable shape, white potter's clay can be formed, dried, pre-fired, painted with kiln wash for separation, and the bottle placed on, thus sagging the bottle into a form. Clay molds on my warm glass page.

Bottles with labels of 3 typesLABEL USE - A cute trick is to soak a paper label carefully off a bottle, sag it to a new shape, then wet the label again [or keep it wet and soft] and form and glue it to the new shape as though the paper label survived the sagging. Use a water soluble glue like Elmer's white glue or mucilage. Treat it like a decal.  More and more beverages are using clear plastic printed labels which can be peeled off, but putting them back smoothly can be a problem.

The bottles at the right show the three styles of labels. The brown bottle has paper labels.  The green one has a closely trimmed plastic label, slightly peeled at the upper curve. The clear bottle has a silkscreened (or decaled glaze) label (next.) Because the mold seam would mess up the applied label, there is an indent below the back label to orient the bottle during application.  The seams are on the side between the labels.  Location of the seams on paper or plastic labels is random.  They are applied to cold bottles. 2010-09-01

Bottle screened label after flatteningThe silk screened 'paint' used on bottle labels (like a glass Coke bottle, Corona beer and this Mexican water brand) is high temp enamel applied while the glass is hot and it will survive being fused. Thus it is possible to take apart a bottle (with a glass cutter), rearrange the words or parts of glass, fuse them together and make a statement (a short one) or decoration with the rearrangement.  Here  is an experiment with a Corona beer bottle re-arranged.  To avoid/reduce the visual damage to the label (as here), it should be flattened or molded with the label not touching the support which may require watching the sagging to use a rod to spread the glass to stop it from folding under.

The creative efforts I have seen with slumping bottles have usually involved using a couple of bottles or cutting the bottle apart, so that a puddle of glass with the form of a bottle when it is done. This cannot be done in one step - the bottle does not melt like ice from the bottom, so the fused lower part must be created then the upper worked to it.

Q: lisa47 wrote:
Anyone know the proper method for melting a bottle down so it lays flat.... about 1/4" think. and still somewhat resembles a (squashed) bottle?...and then it could be used as a cutting board or spoon rest, etc?...Anyone out there ever done this? do you know the proper temperature, length of time necessary, what it should lie on in the kiln, cool down time, what size kiln would I need if I wanted to do 10 or more of these at a time? etc. I don't want to have them melt into a mold of any sort...I want them to each would be slightly irregular!. Please let me know as soon as possible?...(I know nothing about working with glass! thanks! Lisa

A: Almost any kiln (as in borrowed) will do this, but you have to have a peep hole to watch it. It can be done on a kiln shelf covered with kiln wash. Ten at a time is way too many for anything but a custom sagging/fusing kiln and you just can't do this on multiple shelves.
When you heat the bottles laying on their side with elements from above (the best way), the top side of the body cylinder will sag first into the middle, forming a shape useful for holding spoons, etc., before the lower glass has become so soft it melts flat. You should see the glass start to move in the 1200F area and have a full sag by 1300-1350F with flat fusing near 1550F.
When the shapes have reached the shape you want, you have to turn off the power, open the lid and drop the temp rapidly to about 900-1000F to freeze the shape. Then close the lid and let the glass and kiln cool to room temp slowly (over several hours) With this thin glass and lack of manipulation, you probably don't need a more complex annealing, but if they crack, take a look at annealing.
Most kiln are of such a size that you won't get more than 4-5 bottles in. And there is enough variation in heat across a kiln and variation in bottles, that watching more than 5 becomes an exercise in lost bottles.

2002-05-15  I use a shelf wash from Paragon Kilns in Mesquite Texas for my glass sagging and fusing. You will need something if you don't want it to stick to the shelf and not have residue on the glass.  
To take a bottle flat, you need to go to about 1450-1500F.  The problem with taking bottles flat is that they tend to drop the center first, which folds the bottom over, putting it on top of the other glass.  The best solution for excellent flatness is to cut the bottom out first.
You will need to take thicker glass up to about 900F at a moderate rate, say 10F per minute (90 minutes for this rise) to keep from cracking it going up.  Once at this
annealing temp, you need to go to fusing temp as fast as possible.  You need to have a view hole or otherwise be able to peep at the glass without burning off eyebrows, etc.  It will take some time for the glass to get flat.  As soon as it is the way you want it, cut the power and open the lid to drop the temp as fast as possible to about 900-1000F. 
If the glass spends too much time above 1100 it will devitrify, changing partially to a white powder, often looking as if a snail had crawled across the glass leaving a white trail.
  The glass has to be held at the annealing point for about an hour and then cooled reasonably slowly, say over 4-6 hours if not too thick, to 650F, then the power can be shut off and the kiln allowed to cool to near room temp, usually 3-5 more hours.  It is very useful to have a digital controller (about $200) to handle the slow cooling.  


Bottle Cutting Rim Smoothing Cleaning Slumping Neck Stretching Drilling Blowing out Top

Bottle Neck Melting & Stretching

Suddenly there appeared from the internet a thread (far below) referring to an eBay sale (just below, right) and an e-mail showed up with a couple of clues including size and the fact the cooker worked (just below, left.)  So follow my rather sudden progress. 2005-11-05
I am truly stuck. 30 years ago when I worked the carnival route, the big item were stretched coke and beer bottles. The device was invented by Steve Jackson at Viewmont High School in Utah.
It utilized a #10 can on a stand with heating coils inside. The bottle was attached above with a hook. As it heated, it dropped to the stand below, the bottle stretched to a total of give or take 20 - 24 inches. They were given away as prizes.
I have tried on the web to find one of these simple kilns for six months on the web and through carnies to no avail. Can you help me? "
From: "Vincent Verdekal"
To: <mikefirth>
Subject: Bottle stretching
Date: Thu, 3 Nov 2005 17:01:59 -0600
Bottles sold on eBay Oct. 2005 from Lewisville TX

Bottles sold on eBay Oct. 2005 (image with permission)

No. 10 6 2/16" dia  x 7.00" ht. 109.43 fl.oz

 If 1" of frax, then 4 1/8" ID.  Make of hardware cloth instead of steel to eliminate lots of hole drilling.  12.96" circumference - 3 loops= 39", 4 loops=51", 6" straight at each end, bent double to 3" for connections, small IFB chunk for pass through. 2005-11-04

These bottles, which have liquid inside, were emptied and reshaped, then the liquid was returned and the cap replaced.
To make the bottle neck melter, using clues so far, I looked up #10 cans on the internet and found they were basically 6"D x 7"H.  After considering a sheet metal shell and having to drill numerous pairs of holes to support the element, I decided on hardware cloth.  It will give you some idea of the junk in my shop when I mention that I built this from stuff that is around.

The shell or cage is two pieces of the welded wire material called 1/2" hardware cloth.  I could have used one long piece, two was less wasteful.  It could have been one layer, but I felt it was too weak.  Six inches OD times Pi gives 18.85" for circumference and length, so I cut 19.5" to get overlap.  With two pieces, I misaligned the seams (one left, one upper right in picture) fitted the ends of wires into the holes and added 22 gauge wire, twisted to hold together.

Wire cage of bottle stretcher heater with element insulation block
To provide an exit for the element ends, a 1" thick piece of insulating fire brick was cut from a scrap with a used hacksaw blade and trimmed to 2x3". The sides were then cut in 1/2" all around and two holes were drilled at an angle with a carbide bit.  Note that the tools, if not carbide, are not usable for cutting other stuff afterward because IFB is abrasive and dulls edges. Wires were cut to make a 1x2" hole and the brick piece inserted through.  A simple wire U held it although it is probably not needed as the blanket will hold it in the hole.
One inch thick ceramic fiber blanket was cut 7" tall and long enough to fit.  This blanket is sold in rolls.  If you want only enough for this kind of project, check with a commercial heating and air conditioning place where it is used as high temp insulation, otherwise buy the roll from a refractory supplier.  Cutting it long enough to fit is a bit tricky.  For the 6" ID of the cage, it should be 19" long.  For the 4" nominal ID of the unit it should be about 13" long.  The answer is that it is cut to the longer length and stuffed into the cage. (below right.) Bottle stretcher ingredients: frax, coil
The 1000 watt electrical element is one made by Eagle Electric for replacement in old style heaters.  They no longer make it, but Elliott's Hardware, Dallas TX, holds the remaining stock (which I bought when I worked there) and will ship.  Alternately, a 1000-1200 watt element can be bought made up by Giberson and many other sources or wound from wire. In this case, I pulled off 4" at each end, straightening it, and folded it back at the 2" mark and twisting.  This gave a thicker connection point and twice wire so it runs cooler.  The coiled portion was then stretched to make 3 turns around the inside 4" diameter - 39".  If I were making another, I would stretch to about 42-44 for the reasons given below.
As shown in the upper left, a screwdriver was used to make holes through the blanket in line with the drilled holes and the triple loops of the coiled element were fitted inside (below) with the leads through the holes.
The small inserts (right) show the cage stuffed with the blanket, the element positioned inside with no support clips yet, and some of the clay saddles.  The main picture shows an inside view with the clay saddles wired over the coil and through the blanket.  The clay saddles were arbitrarily made of white pottery clay, dried, prefired to 1350F in the annealer and then full fired in the glory hole to about 2100F.  A better saddle might have just the right opening to hold the coil.  The flared corners keep the retaining wire in place.

I was worried about the coil being too long, since it is not easy to recompress.  As it was, it was too short, the saddles compressing the blanket and making the ID larger (the 1" blanket being compressed to 1/2-3/4" thickness.)  So the coils are shown taking shortcuts between the saddles.  I put both hands inside, like a muff and stretched to wires after installation.

Interior of assembled bottle stretcher heater
A short length of 12 gauge extension cord was given a grounded plug at one end and crimped on loop terminals on the hot wires at the other.  A short length of solid wire was butt crimp connected to the ground.  The ends of the elements were looped and bolted to the terminals.  A wire stand-off was twisted in place and then around the cord (right edge.)  The end of the ground wire was bolted to the cage.  3M fiberglass electrical tape was put around the connections to reduce the risk of contact.   A small wire cage was built to keep fingers off the 120 volt terminals. Wiring mount on bottle strecher exterior
The montage at right shows the first bottle done in the melter.  The cage was propped up on the edges of 2 firebricks and the bottle wired in place as shown.  The bottle neck was held between two wire U's tightened to the edge of the cage.  A thermocouple was inserted at the top.  The thing was plugged in and waiting started.  Originally the bottom of the bottle was even with the bottom of the cage so the overall view shows it emerging as the neck stretches.  When the bottle sat on the platform, the plug was pulled.  The temperature was up over 1450F for this fairly thin glass bottle.

Being a long time glass guy, I was really touchy about annealing, so I cooled the piece by lifting the lid and dropping to about 1100, then letting it cool at its own rate.  At a couple of hundred, I took the lid off and released the wires.  Lifting it out with padded tongs, it cooled to air temp without cracking (right.)

Bottle being stretching
The montage below shows details, mostly of the second run with a shorter Coke bottle and the firebricks standing on end.  The cage was turned over so the extra blanket can be folded in to trap the heat better.  The glow of the elements is visible through the blanket.  The final temperature was just over 1500F.  The five small pictures show the bottle emerging from the cage as the neck stretches with the result on the right.  A clock showing the pace would have been useful, but it took just a couple of minutes once the bottom started moving.  (click for somewhat larger view)
Bottle stretching drip montage
To the right is end of one bottle still wired in place, somewhat distorted, showing the coils, while the next picture shows the third bottle with a long curved neck and below that the mess left behind. (click for larger view)

Since the first two bottles survived cautious treatment, I decided to try bending or shaping the neck.  Donning heavy welders' gloves, I grabbed the bottom as it dropped, tipped off the blanket cover and began cutting the wires holding the neck.  Minor disaster - the wires wouldn't cut because they were so hot and my selection of diagonal cutters just mashed the wire.  While I am fighting with the wire, the glass touches the hot coil (still plugged in to a GFCI outlet) and sticks.  So I stop moving the bottle, get a piece of metal to tap the coil free.  The bottle survived the abuse (middle) but now the coil is messed up and will take some careful work - the coil material gets brittle once heated and cooled (bottom.)

So what else - a different grip that does not distort the top, a different release or different cutters for the wire.

Bottle stretch (click to view larger)
All 8 messages in topic - view as tree
Oct 31, 1:37 pm show options

From: "Phil" <> - Find messages by this author
Date: 31 Oct 2005 11:37:40 -0800
Local: Mon, Oct 31 2005 1:37 pm
Subject: stretching bottle necks
Hi there,
Bottles sold on eBay Oct. 2005 from Lewisville TXI know that a similar question was asked not long ago, so forgive me for trying to squeeze a little extra info from you experts. How do you stretch the neck (alone) of a bottle - as I'm sure you've all seen, the neck can be stretched and twisted massively while the rest of the bottle retains its shape.
for example.>>
I'd be very grateful for any guidance on this.
Many thanks

Mike Firth
Oct 31, 1:55 pm show options

From: "Mike Firth" <>
Date: Mon, 31 Oct 2005 13:55:54 -0600
Local: Mon, Oct 31 2005 1:55 pm
Subject: Re: stretching bottle necks
These are more complicated than the previous request, which just involved sticking the bottle in a kiln and letting gravity stretch them. To retain the shape, these would have to be heated to about 1000F in a kiln built for access then a high Btu torch applied to just the neck area, the manipulation done with special gloves or proper tools, held while cool to stiffness, then properly anneal over about 3 - 4 hours.
Mike Firth
Furnace Glassblowing Website

"Phil" <> wrote in message
Nov 3, 9:29 am show options

From: "Phil" <> - Find messages by this author
Date: 3 Nov 2005 07:29:00 -0800
Subject: Re: stretching bottle necks
Many thanks for that info, Mike - greatly appreciated. Could I trouble you with a further question about the detail? I'm sure this would be obvious to me if I knew much about glass manipulation but...
How would the second part - the torching and stretching - be done? Is it somehow possible to apply a torch within the kiln, or is the bottle removed for the torching? The latter seems unlikely, but if the torching is done inside the kiln.... how is this possible?
Please excuse my ignorance, and again - any guidance at all on this would be greatly appreciated.
Thanks again

Mike Firth
Nov 3, 11:36 am show options

From: "Mike Firth" <mikefi...@> - Find messages by this author
Date: Thu, 3 Nov 2005 11:36:30 -0600
Local: Thurs, Nov 3 2005 11:36 am
Subject: Re: stretching bottle necks

Very carefully.
The reason for the complication is preserving the shape of the neck (to put the cap back on) and the bottom.
It would almost certainly require that the person working be exposed to the heat of the kiln and work with the torch within the kiln. The torch would probably have to be one of the "bush burner" style that puts out 200,000+ Btuh.
If they were being made as anything more than a one off, it would probably be worth making a specialized kiln/heating box with a side door (instead of trying to work in a kiln with a top opening door) and then move each one to an annealing kiln after shaping.
Just stretching the neck and letting the bottle parts flatten in the heat is much easier, it is preserving the shape of top and bottom that makes it tricky and hot.
Mike Firth
Furnace Glassblowing Website

"Phil" <> wrote in message

Randy H.
Nov 3, 4:01 pm show options
From: "Randy H." <> - Find messages by this author
Date: Thu, 3 Nov 2005 14:01:51 -0800
Local: Thurs, Nov 3 2005 4:01 pm
Subject: Re: stretching bottle necks
I saw how it was done many years ago at a local fair. They used an electric heater that was in a sleeve just large enough to fit around the bottle neck. Just tall enough so the bottle top was exposed out the top. It would heat only that area of the neck. I believe the bottles were suspended in the air by the top of the bottle neck. When the glass got hot enough the bottle would start to drop. At that point is when you start to make your twists. I know this sounds crazy, but they are not annealed after that. Proof in point........the labels are still on the bottles!
Randy Hansen
SC Glass Tech.
Mike Firth
Nov 3, 6:39 pm show options
From: "Mike Firth" <mikefi...@> - Find messages by this author
Date: Thu, 3 Nov 2005 18:39:36 -0600
Local: Thurs, Nov 3 2005 6:39 pm
Subject: Re: stretching bottle necks
Perhaps the original poster (someone) contacted me with a somewhat similar description. I just replied. They referred to a #10 can sized sleeve.
The labels shown on the bottles on eBay don't count because they are screened paint and will survive the heat, in fact are applied while the bottles are still hot before original annealing. One of the sporting things I have done is cut Coke and other bottles apart, rearrange the pieces, and fuse them to hanging things - the print survives. The bottles can also be sagged flat and have the printing survive.
At this link warmglas.htm#FUSEDBOTTLE  is an experiment with a Corona beer bottle re arranged into a fuse bowl. I ended the description in the reply with "and pray" because of the lack of annealing.
Mike Firth

Nov 3, 8:58 pm show options
From: "Randy H." <> - Find messages by this author
Date: Thu, 3 Nov 2005 18:58:16 -0800
Local: Thurs, Nov 3 2005 8:58 pm
Subject: Re: stretching bottle necks
Hi Mike,
I guess I should have looked closer at the bottle label!
I have a bad habit of scratching off the label with my thumb as I slowly savor the evervesence of my beer of choice. That way I do not mix my bottle up with someone else's.
I think you're right about the Corona, but I'm not sure about the Bud Light bottle. I think this gives me good cause to buy a six pack and do some investigating!
I agree 100% on the pray without annealing!
Randy Hansen
Mike Firth
Nov 4, 7:37 am show options
From: "Mike Firth" <  Date: Fri, 4 Nov 2005 07:37:08 -0600
Local: Fri, Nov 4 2005 7:37 am
Subject: Re: stretching bottle necks
With paper labels you have to soak them off and glue them on again if near the heat.
I am thinking of making a can to try and do it - I have the parts on hand.
The guy goodthngsdontlast selling on eBay says "yes that is fine i make them and if you have any questions please let me know"
Mike Firth
Thank you again, the article particularly at the end gave me an insight how I must proceed. Last night in Devine, Texas (an exit on the freeway to Laredo) I met an older carnival owner who 30 years ago had four of the portable heat kilns that  I want to make or buy, unfortunately, however, he had no idea what has happened to them. His heat kilns used 220 volts. He said he used four (4) at a time and that by the time he had hooked up the four kilns with bottles the first bottle would have already dropped.  He claims that stretched bottles went out of favor because so many were broken through careless mishandling by customers that the stretched bottles  were banned at most fairs and festivals due to possible danger that could occur among the large amount of people at these events. Next week I intend to peruse the links that you gave me.
Thanks again

Blowing out

"I love your site. I know nothing about glass. I have a question though... Would it be possible to reheat and then reblow a magnum or double magnum champagne bottle into almost a sphere? Or at least a pooched out champagne bottle? "

 In principle, yes. Reworking a bottle of some smaller size is something almost every modern glass blower does at some point. The method is to preheat the bottle(s) in the annealer so they are about 1000F, below but very near the point where they will sag of their own weight. From a broken piece of a similar bottle, glass is melted on the end of a blow pipe. This step is necessary because ordinary art glass melts at lower temperatures than bottle glass and using art glass as the bond makes the connection uncontrollably soft, even with beer bottles, much less the heavier wine bottles. The glass is heated, flattened and shaped, the end of the pipe reheated and brought in to match the opening in the bottle, making a good seal. The bottle is lifted out and taken to the glory hole where it is brought up in temperature until it is soft enough to begin to blow out and shape. If the bottle is too cool going in, it shatters (or cracks) perhaps making a real mess in the glory hole.
Working any bottle is awkward because instead of starting with glass gathered on the end of the pipe and working it out with a relatively short neck, the heaviest part of the glass is already way out there on a relatively long, but pretty cool, neck. A wine or Champaign bottle is worse because there is so much glass in the thick bottom, including the punt. Also, although I couldn't find a neat set of heights on the internet, the magnum appears to be about 400 mm tall (15.75") and an eyeball estimate puts the double magnum at about 500 mm (20"), which means there is a lot of glass a long way from the end of the pipe. Not all glass workers are able or willing to work a piece they made themselves that is 18-24" long, 12" being large for them, and starting with a piece nearly that long will take an assistant and perhaps some specially prepared blocks and pads to shape it. I would certainly expect anyone who was willing to explore it to want to start with ordinary wine bottles for a couple of tries before tackling the two bigger ones.
Hope this helps,

Turning Out

Bill Riker flared neck milk bottlesIf a bottle is preheated in a kiln, it can rather easily be picked up from the bottom on a punty (unlike the difficulty mentioned above using a pipe on the top) in order to flare or turn out the top. Bill Riker reworks milk bottles as shown and other types shown on his site. Because of the evenness of the rim we can be pretty sure these were reworked in a glory hole rather than with a torch.  As with a pipe, it is important to melt similar glass on the punty end rather than using art glass because of the different melting temps - a broken piece of bottle preheated in the kiln and picked up by the thin skin left on an almost clean punty can be melted to make the knop.
Once picked up well centered, the bottle can be raised in temp and flashed periodically while heating the rim at the glory hole door.
Straight sided bottles can be opened to make glasses although I think I would trim the neck to have less glass. 2011-11-20

CLEANING BOTTLES - If you have to clean out narrow necked containers, plastic or glass, of material like mold, dirt, wine stain, crystallized sugar, etc., a valuable trick is to keep a couple of tablespoons of aquarium gravel.  These small stones have rounded edges and when put in the container with water and soap or other solvent matched to the stain, can be swirled around the inside while holding the container horizontal with my hand over the neck, providing a scraping action that is hard to duplicate with a brush.  When done, I pour off most of the liquid then give the bottle a swirl and turn it upside down in a small container so the gravel pieces fall down into the neck and then into the container without being driven by the bulk of the fluid even if the container overflows.  Then I pour off the liquid in the small container and use it to store the gravel for next time. 2009-12-19
Slumping Neck Stretching Drilling Blowing out Top

Back to Sitemap

Contact Mike Firth