Mike Firth's Backyard "Studio"

Rev. ...  2002-08-10, 2003-03-01, -08-15, -09-06, 2006-04-02, -06-26, 2008-04-29,
2009-03-04, 2010-02-11, 2011-01-01
[Search on date pattern to find latest changes, more than one may be found.]

Working Glass Outdoors and keeping equipment there.

I mostly blow glass in my backyard (although I appreciate the kindness of several studios in the area that let me blow there occasionally.) My "studio" has a roof to keep rain from drowning the equipment. I work under the sky, using a sunshade when the sun is especially hot. On this page are pictures of my equipment with comments on building it, links to more detailed discussions and comments about using equipment exposed to the weather and great changes in temperature and also about working outdoors in various wind conditions and temperatures.


Local Links
Bench Annealer Glory Hole



Burner Tools
Other pages
Foundry Mike Firth Glass Tool Making
Backyard plan pretty much to scale At left is a plan, pretty much to scale, of my backyard with identifying letters used below.
H - house, driveway to top, street off left
G - Garage/Shop
AC - Air Conditioner compressor
A - Rain shield for small forging, etc.
B - Brick U BBQ unit
C - Wood frame lean-to cover for annealers
D - Metal frame concrete pad for furnace/glory
b - bench
m - marver
c - wet tank on stool, bucket below
a - 3rd arm
f - tall fixture for area light

Diagonal line at bottom is lot line (lot is parallelogram).  Other side lot line is about 10 feet up from top edge (lot is 50' wide)  Alley is about 30' beyond right edge.  Large gate in fence gives access to narrow paved alley.

BENCH - I have back problems and, in fact, stand most of the day at my work. Getting up and sitting down repeatedly bothers my back much more than standing. I can and repeatedly do work glass from a regular bench when visiting shops, but when I began thinking about making a bench, the idea of standing up and a sketch of an ancient standing bench (with the marver slanted over head) encouraged me to work out the bench shown here. (Image below from Harvey Littleton's book, a Search for Form.)
Old style blowing "bench" from Harvey Littleton's book (click to enlarge) My standup work bench with marver
Outdoor work bench with third arm and pipe holdera above
Among the details in the drawing are that the arms are L shaped with the edge up, which tends to shed any glass drips or other interruptions to rolling - flat topped arms are commonly used on sit-down benches. A metal tab sticks up on the end of the arm to keep a pipe from rolling off if I walk away briefly. The arms are much shorter than on a sit-down bench as they don't have to reach past my body from the back rest or allow for the elbow to palm distance there. The cross bar at the top, besides being structural, is drilled for 1/4" carriage bolts that allow hanging tools at eye level.  The cross bars several inches up from the ground fit my plan of being able to lift my equipment but are also L shaped to take a shelf or blocks of weight. Hinging the marver (next) allows quick removal as its pivot is just a longer end piece set inside the uprights. 2011-01-01
Drawing of standup work bench with side mount marver
Glass tools laid out on marver of standup work benchNotice that the marver (m) is hinged at one end and tools are hung up on the rail on pegs which are just 1/4" carriage bolts (which have large round heads. (well, that doesn't show well in the picture right, a shield is hanging from the rail, top right.) The bucket of wet wood, once kept on the platform, now sits on a waist high stand after I kept getting the marver wet. To the right is a third rail (above), on a separate stand that holds the end of the punty while I am attaching it. The length of the rails is based on how far my arm will stretch when I stand and reach (I could make them longer and step forward while rolling the pipe, but I didn't.) A pipe hanger is located at the top right corner (see above.) Between the picture above and the one right, the plywood panel was replaced. On the plywood right, the white mass is frax in a Corningware bowl that is a catcher for ornaments while the loop is added to the top. The round tubes are for making marbles.

ANNEALER - This is my annealer which is small but meets my needs so far. (I am working on one in a refrigerator shell.) It is a 24 x 30 inch box with 6 inch thick lid. When first built, it had 6" of frax insulation all the way around and a 12 amp 120 volt element (Kanthal from Dudley Giberson) would take it to fusing temperature (1550F) albeit slowly. The insulation took exactly one roll (50 board feet 2" x 24" x 12.5') and was designed that way. Since then I have taken out part of the inner layer from the walls (so now 4" on the sides) and use it just for annealing since fusing is not of great interest to me. Recently the element was broken (by dropping molten aluminum on it, if you must know) and I installed the new element on the lid rather than on the walls to give me more space to lean pieces against the wall. 5/1/2000

The stand has wheels at one end (hidden by the white bucket on the left) and the white shelf to the right also serves as a handle for moving. Resting on the shelf are the controller covered by a Plexiglas cover I made. The controller came from Love Controls and is a single ramp, self-learning controller that cost about $200 and is about 2" x 2" x 4".


Annealer with rain roof in place
The lid is counter balanced with a concrete block hanging from an eye-bolt on an extension of the lid handle. I do not like springs which have to be carefully placed to balance the lid in most positions. By using an eyebolt down from the handle, the block swings under the lid, close to the annealer, being almost neutral at the lowest position. The lid actually has no hinges, resting when open on the shelf shown at the back. The weight can be unhooked and the lid lifted off at any time. Actually a light chain prevents the lid from flipping too far open from its own momentum. The 1x2" wood handle is fixed to the lid with 2"x1/4" bolts that were installed from the inside, through fender washers, when the lid was made. 5/6/2000 Sideview drawing of annealler showing hinge shelf and counterweight
In this shot (click to enlarge) the parts of the annealer are well shown. The bar with the block handing from the eyebolt. Notice that the L shaped catch rail shown in the drawing is not in the photo. It was taken off when the new steel frame was made and I have not installed anything new. I don't trust the lid to just gravity (there are not hinges, so I can lift the lid off fairly quickly when I need to.)
Visible as a dark diagonal line at the back is the chain that keep the lid from flopping over. The loop just at the pivot is a ground wire tying the lid to the body. The tan running through it is the power to the element in the lid. The black blob against the white insulation is the socket for a small (7-15 watt) light bulb that goes on with the element.
The white panels on the end are explained below.
Annealer with lid standing open
This is a shot of the annealer open showing the connections for the first element on the end, and the second element pinned to the lid. At the present time the first element is broken and has the broken ends hooked together, having a higher resistance and thus not getting the box up to 900F. The wire of the first element is held away from the metal box by the pieces of cement board/asbestos shingle that show white and connections are made to brass bolts mounted on the shingle. Normally, the connections are covered with a heavy wire screen to keep fingers off of them. The upper element has its leads passed through a chunk of insulating castable, not a best choice because it has never been fired and picks up moisture from the air; a chuck of insulating fire brick or broken fired castable would have been a better choice.

The frame below is the new welded one, from 1/2" square tubing, not yet painted and without wheels. It replaces one shown in some other pictures made of wood that lasted for about 9 years. 2001-06-07


Annealler showing insides and elements
Metal tubing frame for annealer  

GLORY HOLE - The glory hole I use is the second construction (see Hot Glass Bits for discussions of early efforts) and it is perfectly standard: a 30 gallon drum, lined with insulating board glued to the walls then lined with insulating castable. The only unusual construction choice is that rather than cutting the barrel shorter and rewelding a rim, the depth of the hole was set by pouring a mix of vermiculite and water glass in the bottom to about 6" and then pouring a layer of castable on the stiffened mix. Thus the bottom/back was well insulated and the depth of the hole is not so great as to waste heat.
 The other oddity is the flat pot you can see through the door, called a boat by some, which is made from a formula gotten from Independent Glassblower #11 and reprinted and explored in my notes on making crucibles.
Glory hole with flat crucible for melting glass


FURNACE - Notes and furnace under construction furnaces.htm

DOORS - The doors above and below show my preference in doors - cheap, light and well balanced with long handles well guarded from the heat. The wheels are at the bottom, made from cast pulleys with a bronze bushing inserted. A guide/guard rail keeps the door from flopping back or running off the ends. The track is adjusted in and out to place the door so it will lean against the opening lightly. When the handle is grasped, and it is in the "shadow" of the door so it does not heat up and can be grasped bare handed, the door naturally comes back from the opening and is balanced on the wheels, being very easy to move.

The door below, cast in a pie pan, is not a good choice, because the castable cracks across the bolt lines. It should have been cast in a band of steel with a bolt adjustment for tightening, [Which was done with its replacement, here] (The unit on top of the furnace is a 1000 watt heating element set in a groove in a block of castable that is used for drying out and preheating the glory hole and furnace when they have not been used for some time in wet weather.) See doors.htm

Glory hole door and face while hot Furnace door, furnace, preheating block

BURNER - This is a perfectly standard burner arrangement that might have been built from the drawing in any of several books. The blower is the one Dudley Giberson suggests from Grainger Industrial Supply. One odd point is the air valve, which is built from wood with a sliding section. The grey 2"PVC pipe is glued to the wood but not to the white PVC reducer. (I use the blowers on other devices, include metal melting.) The pipe is 1 1/2" black iron with the flare piece at the end being 1.5" to 2" (about 2.75" OD) for swirl and flame retention. (The galvanized coating shown burned off the first time it was used, the piece in the picture being a repair.) The gas feed is high pressure (pounds, not ounces) and is fed to a brass tube with a treaded cap center drilled with a small hole. The tube is fitted through a drilled out brass reducer bushing so it can be adjusted to work fairly well - sucking enough air - if the blower is not on, giving a sort of fail safe operation. Burner Building  Glory Hole Standard type of homebuilt pipe burner on Glory hole

Closeup of alternative tools on marver

TOOLS - While it may be useful and pleasant to have several hundred dollars in tools at hand when working glass, it is not necessary and most glass workers have one or more tools that is really cheap but handy and useful. Ironically, now that I see this picture on the screen, the most heavily used tool and most homemade is not in the picture - I made my own jacks.

Tool Name Used For Source

Est. Cost

Official Tool Has


Needle Nose Pliers Pulling and twisting glass Found, but also hardware store. $10.00 Same $10.00
Diamond Shears Cutting and shaping glass, maneuvering pipes and punties ARTCO, other suppliers $65.00 Same $55-150
Knife Chilling punty line for crack off Found $0.00 Same $3.00
Tweezers Pulling glass, picking off flaws, guiding punty Hardware store, cheap tools bin $3.50 Bent tip $15.00
Scissors Trimming glass Found, but hardware and grocery stores sell them $0.00 Straight Shears $40.00
Ducknose Shears Trimming glass (these are sheet metal shears) Hardware Store $15.00 Longer Nose $30.00
Jacks (not shown) Shaping Glass Made from flat stock $5+hours Jacks



OUTDOOR GLASS WORKING - My equipment is outdoors, which leads to certain problems. Some of these problems apply to any studio that is somewhat exposed to the outdoors, such as Art Allison's enclosed, but unheated (except by the furnace!) place.
  • BUGS - In Texas we have these mud daubers that look like small wasps but don't sting. They do, however, try to make a nest wherever they can, which includes the holes in blow pipes, which they fill with mud which dries hard. An internet discussion suggested golf tees or small pieces of wood to block the opening and said any location with open walls has the problem. The most obvious suggestion is to make sure the pipe are clear before using them.
    Mosquitoes are a major problem in the south, especially with West Nile Virus around.  Any container of water, like a block bucket or crack off bucket, can show larvae.  But the answer is easy - go to a hardware store or garden center and ask for a bottle of the small grits or granules of BT mosquito larvae control. These are sold for small ponds, birdbaths, water gardens, etc. BT is Bacillus thuringiensis which is a living organism that attacks wiggly larvae - it is used on worms on plants in other subspecies. Although the bottle in front of me does not make the claim, one brand actually said it makes the water better for birds by adding protein.
    This stuff looks like grape nuts. Instructions call for a teaspoon for every 25 square feet. Think about the size of a bucket. 5-10 granules is enough for a bucket. In my bird feeder and block bucket outdoors, one application is good for about two weeks. The container says 7-14 days. I usually go out about once a week and look at all the water standing around and either add a few granules - the bottle has a shaker top - each time or more if I see larvae.  The stuff starts to work very fast in the immediate area of the granules - you can see the larvae start to wiggle frantically and die, but it takes a while settle to the bottom and to drift through the water, 24 hour kill per the bottle. The stuff is also sold in blocks (Mosquito Dunks brand from this company) but these are for ponds and a waste of money for adding to a small container. If kept dry, the stuff lasts for years. Read the label before you buy and contact the company involved if you have concerns. There is a skin contact warning, but I take this to mean for the granules, not the water with a reasonably small quantity in it. [Confirmed by e-mail from the company]  Summit Chemical - Mosquito Bits 2006-04-02
    Wood is chewed to shreds by various bugs, so anything on the ground must be pressure treated. One reason for rebuilding the support for the annealler in metal was the deterioration of the the wood at the bottom.  Pressure treated wood on and near the ground is a partial answer.
  • RAIN - The metal frame and corregated roof for the hot spot in my backyard.Obviously, gear needs to be more or less protected from the weather, including rain. In addition to the discussion of temperature changes below, insulating blanket, castable, and fire brick can absorb water and if heated too fast the water can flash to steam blowing apart the material. Water in blanket can so lower the insulating value that it may take days to cook it out. When I left the lid of my annealer askew when rewiring it and it rained, I drilled a pair of holes in lower part of the case and water dribbled out. In a picture above, a heating element is shown that I use for drying out the gas heated gloryhole and furnace to drive Wood hut for annealer shelter in backyardoff moisture over several hours. If the humidity has been high or there has been a lot of rain, I pre-dry the gloryhole.  I commonly keep my annealer on and set to 90F so that it is warmer than the outside air at night most of the year. [D above]
    Still being used, but built earlier, is a wood frame hut, also with open sides, [C above]   This picture is from 1999 at a time of garage reconstruction.  The trees behind are now grown over it and at one point a mass of thorny roses grew over the top - since died and torn out.  Although braced, when there was no Covered yoke with glory holebottom connection, the legs were forced out, bowing the top down, which was corrected by jacking the center and using a ground level wire across the back.

    At right below the glory hole door is shown a roughly bent sheet metal cover for the yoke which protects the two ball bearing transfer units shown here from water damages.


  • TEMPERATURE CHANGES - Obviously, when the temperature drops through freezing, water buckets and other wet places need to be protected or emptied. And high temperatures can melt wax used on tools.
    As the temperature rises and falls each day, equipment can be damaged by the moisture from humidity. Part of my annealer is rusty from this process. It happens because the temperature inside the annealer is always "behind" the daily temperature changes. In the evening, the inside may be 85°F while the outside air has cooled to 60°F with high humidity. As the air in the annealer cools and contracts, humid air is sucked in, cooling on the metal case and getting the whole wet. I have recently been setting my annealer at 90°F to avoid that fluctuation, especially into the higher humidity range.
    Pipes can collect water inside and can condense moisture from the breath when cold enough. There was a thread on this problem in cold studios, not just outdoors. Besides corrosion that can occur, there is a risk of being burned, because when the water drips on the hot head, it flashes to steam which rapidly heats the pipe for several feet back from the head. Solutions include blowing out the pipes with compressed air, storing them on a rack above the furnace, and having a pipe heater that holds the pipes at an angle so air flows through them.
  • GROUND CONDITIONS - 5.5 x 6.5 foot concrete base poured to get equipment under metal shade and out of dirtWhen working outdoors, it is better to have a concrete slab and probably better to have a pounded bare floor (like a blacksmiths) than grass, but Art regrets not putting a slab in his otherwise enclosed studio because rain does blow in and the dirt gets slippery. A slab clearly costs money and effort, although I managed to put a slab in my garage without killing myself. One problem with a slab is that it places clear limits on the space and walking off the edge tain't fun (if digging down for a ground level slab is out of the question.) [Picture shows 5.5 x 6.5 foot raised slab installed to get equipment out from under wood frame roof. D]
    • GRASS - Looking at some of my pictures will quickly reveal that grass grows everywhere and cutting it is not one of my favorite activities. And I don't like killing it with kill-all chemicals. So I have a gasoline powered string cutter for trimming and try to arrange things so mowing is not incredibly difficult. A good point of grass is that if you drop a piece and want to, you can usually rescue it unbroken. Several of my pieces have carbon-from-burned-grass images on them.
    • DRY GRASS - Texas has long periods in the years with little or no rain where the grass dries out and causes a fire hazard. I trim more industriously and keep a garden hose ready with a cutoff valve at the end for quick use. I usually wet down the area around the gloryhole first.
    • SOFT GROUND - While the dirt in our area turns to the consistency of concrete when really dry, it absorbs water like a sponge and it is possible to have 2" of rain fall in the yard and have no run off. When the ground is this soft, equipment has to be planned for it. Even if I had a concrete slab [added in 2001], I am not sure I would mount casters permanently on the equipment, which is heavy enough to require costly casters that are hardly used and will dent under the weight with time.
      In any case, I build my equipment with rails at ground level on the sides and 6" up on the front and back. This is most easily visible on the bench above. The side rails provide plenty of area to keep the units from sinking into the ground. The uniform height of the front and back means I can either roll a caster rig under the rails or lift the unit on to taller casters. I have a fairly expensive set of casters that will carry 4,000 pounds which I keep out of the weather and to which I rig various platforms for moving scaffolding and glass stuff. In reality, the 6" rail height is too low for these casters and it gets lower as the side rails crush the dirt and grass, so I usually end up levering the side rails up onto 2x4's before moving.  Pressure treated 1x4's or 2x4's laid flat would reduce sinking.  If I had to do a lot of moving, I would weld up a low rig with a jack or screw built in and get casters with wider soft wheels to avoid sinking into the soft ground.
  • AIR CONDITIONS - Air in Texas is memorably hot and is wet more often than I like to consider, especially in recent years. See notes on humidity & temp changes above. When the wind is blowing, shelter from the sun must be anchored (next). It is also very drying, beyond the exposure to the furnace heat, so I keep water, soda, and Gatorade on hand (buy Gatorade in powder form - 1 gallon envelopes or bigger - at sporting goods stores or jars on the top shelf of grocery stores to save money over bottled.)  I have a couple of floor fans that don't get much use; I find shade is more important outdoors. Ventilation choices
  • LIGHTING - In bright sunlight, it is possible to work with a #5 welding shield in place and still see to maneuver although best practice suggests not.  At night, background lighting is required for safety and detail lighting helps. Overall and security lighting are provided by a yellow high pressure sodium fixture that is very efficient and long lasting and comes on every night automatically, giving reasonable lighting for the whole backyard from a mount about 15' up on a conduit set above the corner of the garage.  Further area lighting is provided by a 75 watt ordinary bulb mounted on a 10' pole [f]above a (barely) moveable concrete base; an aluminum shield guards the bulb from rain and reflects half the light back down.  Under the edge of both shelters [C D] are bulbs, some CFB's, just above my head, controlled by switches centrally located. 2008-04-29
  • ELECTRICITY - Working outdoors demands added steps for safety with electricity since all metal must be assumed to be grounded and a path for a shock and when the ground is damp, that is another path.  All my electrical outlets are up under the roof of shelters just above my head and all are fed by GFCI's. All wiring contains a safety ground. 2008-04-29


  • SUN - Working outdoors in Texas means sun a fair chunk of the year. I don't like getting burned or cooked, so I wear long sleeve cotton shirts or work into the evening or put up shade. After several attempts with tarps on poles and tent-like arrangements - which the wind played havoc with and which were hard to relocate - I welded up a frame.
    The vertical posts are 8' long and the unit is 4' wide. Everything is 1" square 16 gauge steel tubing. Thru the angled upper part, I insert 10' long 1/2" conduit pieces on which I drape a blue plastic tarp fastened to two more 10' conduits, (originally) lashing the conduits together. Instead of trying to put a set screw in the angled part, I braised a 1/4" nut to a short piece of square tubing and use this as a stop collar on the tubing. The cross bars are positioned so the lower is high enough to permit picking up the unit with one hand low and the other high so it can be moved rigged. On windy days, I hang a chunk of concrete from the lower crossbar.
Portable shade, drawing, made of welded tubing
  • Welded sun shade set up with conduit supporting cheap blue 8' x 12' tarp.  Originally, the cross bars were lashed into place. This required tipping the frame forward to get it into reach, often awkward, taking up a lot of space in a small clutter yard and catching over head. Recently (2002-06) I added three T's made of 3/4" conduit tubing that slide on the upper bar of the shade. The outer two fit over the side 1/2" conduit to keep the cross piece in place and the middle one receives a piece of spare conduit for lifting the shade into place. Originally, I thought I would be lifting the whole from this end, but that turned out to be very awkward. So I set the whole near the bottom, tie the lower bar in place and lift the top bar into place (I am 6'2" and can reach it from the ground.) To keep the center under control, a short rope is stuffed around it to jam the T so it wasn't too loose.
Welded sun shade set up with conduit supporting cheap blue tarp
  • The latest addition to my outdoor working is this 7 foot long rain shield for the rack full of heating things - insulating castable and fiber kilns, foundry Firehole and forge.  The metal tubing is 1/2" thin wall conduit with two straight pieces for stiffening along the edges of the corrugated sheet metal, all of which is drilled together with self-drilling big head sheet metal screws.  The curved sections were bent with a conduit bender.  The verticals that curve to the right move the pivot point back so the raised position is more out of the way and the lowered covers the hardware front and back.  Extra conduit was left to one side of shield, drilled 1/4" to provide a pivot.  Similar drilling on the verticals and bolts make the pivot.  In the raised position, shown, a rope ties it off.  In the lowered, a chain runs from the vertical to the end of the extra. 2003-08-15 [A]


Shield for foundry and forge items.

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