Tool Making for Glassblowing

Rev. ... 2003-01-19, -30, -04-03, -07-07, -08-28, -09-24
2004-01-30, -04-09, -05-10, -05-13, 2005-11-01, 2003-02-13, 2006-10-24, 2007-05-09
2008-09-09
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Hot Glass Bits 2003 Notes
Glossary of Glass Tools

Tool Making for glassblowing varies from simplistic to complicated beyond the ordinary mind to deal with. Here are a few thoughts on making things. See also the Glossary of Tools

Some of the easiest tools to make are wood dowels soaked water. Further at Blocks, Paper & Wood
I am working on a glass garage to park glass hot. It has its own page.

For views of equipment (as opposed to tools) see m-bckyrd.htm and workalon.htm

My homemade jacks, hanging up>
They were made from 1/2" x 1/16" plain steel. They leave black rings on glass if not well waxed on the sides. The hardest part in making them is getting a thin edge on the blades without curving them - if I were more skilled and interested in grinding, it would probably be easier. The second hardest is getting the blades to come together parallel and in line. Jacks with a wider curved back will more naturally stay in line; the narrowness here means awkward squeezing of the hand can misalign the jacks more easily. Note that the two blades are twisted opposite of each other. I made one pair where both had the same pitch and they were more awkward to hold and fit to the hand. -

Rollers for threading and track for stringer making

Two devices were combined here. A cart was made to carry a pipe and hold a torch aimed at the glass on the pipe, so stringer could be pulled, which would land on the sheet metal catch. On the cart are mounted pairs of wheels for patio doors. These allow the pipe to be rotated freely. The mounts for the wheels can be pivoted which causes the pipe to translate lengthwise as it is spun, so threading will leave evenly spaced lines in a spiral. The cart can be used alone for the spinners.
At the right end of the tray is an elbow mount of a fixed hook and a hook in bearing, to provide anchors for the end of stringer or rod in the making.
On the cart is a pivoting arm which has a cross piece that also pivots and two bolts project to hold a Hot Head torch by the mount made for it.

Torch mount
This is the mount for my Hot Heat Torch, which is needed for hands free use and because the torch gets really hot after being on for a while. It is shown after a repair resulted in a straight tube. The mount still has a groove cut in it to accommodate the original bent tube. The mount consists of 1/2" square steel tube strapped to the torch with stainless steel hose clamps. The mount has two 1/4" holes drilled to match bolts sticking from a L shaped base. The threads of the bolts help keep the torch in place. The "base" is simply 1/2" steel tube - a 12" piece with a 2" piece welded to it at a right angle. The 2" piece was drilled and tapped to take 1/4" machine screws (round head) 1-1/4" long. The 12" tube is drilled near the bottom to slip over a bolt sticking from the front of my work bench is the hole has been more often used C-clamped or held in a vise. The same holes permit mounting to the thread puller rig above.

Torch Repair
I managed to drop a garage door panel on my Hot Head torch and snapped the tube just at the base of the threads. The tube is not available as a repair part. Once I started working on the project, I took it to the end, although I probably spent as much as buying a new torch. The threading turns out to be 8 mm 1.0 pitch and the Store sells that die ($3.50) I tried making a tube from 5/16" thin wall brass tubing doubled with the next size smaller ($3.00) and from 5/16" thick (0.032) wall tubing ($8) and both were too thin and tore apart when threaded. 5/16" (7.9375mm) is 99.21875% of 8mm, so I bought the longest 5/16" brass bolt the store had ($1.50) and a 5/16" ID sleeve ($1.60) and after threading the ends, stood the bolt on end in a vise on the drill press table and used the sleeve and short pieces of on hand tubing to reduce and center the bit and drill the bolt 3/16" as far as I could from each end, which was enough to break through. (While I was doing this, I realized the same sleeve tube could be soldered to the center of the bolt to make a longer tube if I needed.) After machining, the ends were carefully filed square and the whole cleaned with mineral spirits to remove all scraps of metal and machine oil (to keep the tiny orifice in the head clear) and the torch was assembled. It actually leaked the first time and was disassembled and some selective filing done. Works fine now. 2001-12-30

Preheater for damp glory holes and furnaces - 1000 watt coil set in grooves in castable. VERY DANGEROUS with exposed 120 volts AC at the bolts on the front end - should have a wire cage over the terminals and heating elements. It is only used plugged into a GFCI and is normally moved only when unplugged while wearing gloves anyway because it is hot. High temp wiring used for ovens and stoves is attached with porcelain wire nuts to short pieces of solid copper covered with insulation tubes to reduce heat load on the insulation.

Rod Optic
While a ridge optic is a major casting operation, a rod optic is much less complicated. It can be nothing more than a set of rods arranged as needed. Using the layout at the right (click to enlarge and print) it is possible to make a plate that will support rods at 3, 4, or 5 parts of the circle. (Six is easy, either draw radii around the circle or extend 3 lines through center to other side.)

I used 1/4" steel plate and drilled for 1/4" bolts/rod. I wanted the rods at an angle, so I mounted the plate at an angle by drilling a center hole, putting a screw through it and screwing to a piece of plywood which rested on a shim block. Before tilting, I center punched each hole through the paper and brought the bit down to enlarge the punch to about 1/2-2/3's the hole size. I then placed the board in place and loosened the center screw just enough to let me rotate the plate. I positioned the first hole and clamped the board in place. I could then rotate the plate after drilling each hole and have identical angles around the circle. I made rods from 5 long bolts by cutting the head off (and later cutting some of the thread off when I found the excess thread caused problems.) Having made this and used it, I think I slightly misplaced some of the holes, so I get uneven lobes; I am going to have to check. In making it again, I would use the turntable I made for the wire winder. [Which I did, see next.]

Here is what the plate looks like setup. The holes are drilled to allow 3, 4 or 5 rods to be installed. The three holes drilled in the corner are used for converting square rough cut wood pieces to dowels for making cherry wood dowels to pin stuff together.
Piece blown in rod optic with three rods. I like the triangular mouth. Haven't tried equivalent with 5 sided.

This is the rig I originally built for drilling the 7 holes in the wire winding plate, but here it is set up for redrilling the rod optic plate (below) so the circle of rods is further out to make larger pieces.. The pattern above was printed out, the lines extended to make a 6" circle and that cut out to fit on the disk. The disk is mounted on a small lazy Susan bearing screwed to the rectangular wood plate. A center hole was drilled in the optic plate and the paper and plate were lined up over the existing center hole and a screw placed to hold it. The plate was turned to line it up a bit and the screw was tightened. On the drill press stand, one of the vise mounting bolts was used to keep the base board from moving sideways and a 3/4"

scrap wood piece was inserted under the base plate to tilt the unit to about 15 degrees, matching the previous drilling less a little bit. The hold down is a commercial modification of a ViseGrip handle bolted to the press plate. The corner iron, as shown at right, is the line up reference. If I were trying to put the holes in exact locations on the plate, life would be more difficult, but since I just want the holes to fall correctly with respect to each other, I just line up the first hole, clamp, drill, and move the turntable so the next line aligns the same way. When the clamp is tightened, the plate actually revolves a bit, so I readjusted to get it to lineup after clamping. Since I didn't move the base, all the holes end up on the 2" circle aligned with the drill bit. After drilling, I removed the plate and used a manual tapping handle and 1/4-20 tap on each hole.

This plate was made up to twist wire like that shown (and about 30 10-12 foot pieces scrounged from a trash pile across the street) into goblet bases and wire rope. It was made by first building a turn table of wood on a small lazy susan bearing with a paper disk for the 6 points (from a CADD program) (above)
The rod optic would have been better made if I had built the turntable then, so the rods would have been completely uniform - I could have tilted the platform and clamped it down and still rotated the top, to keep the angle and spacing exact - I had to line up each hole on a tilted block by hand.

Cylinder Mold
This is nothing more than a piece of conduit - 3" nominal - with a bottom welded on.  A disk of cork was placed in the bottom and the pi divider used to make an inside liner.  Holes were drilled near and in the bottom to release steam.  The tube is soaked in water before use and the cork swells until the edges meet.  It is used to blow cylinders for whatever purpose, including cutting to make flat Spruce Pine compatible sheet and tumblers. 2003-09-25

This is the second cast puffer head, much smoother than the first. Aluminum is tapped for 1/4" water pipe (about 1/2" OD) and the fitting shown allows the copper tubing for blowing. A reducing fitting 1/4" to 1/8" allows screwing it onto a standard air valve for a shop blower. [I have since changed out the rigid tube to a snap on air compressor fitting that I put large clear tubing over for mouth use. Also built a larger diameter flatter cone for bigger mouthed pieces.] 

From: "Jeff" <julrich@qwest.net>
To: <mikefirth>
Subject: Cheap tool additions
Date: Tuesday, March 19, 2002 6:09 PM

Just discovered your site...wonderful. I have been out of glassblowing for a few years doing "the day job thing" to survive but the call to the furnace is too great. I am renting time at another shop until I formulate a plan to quit my job. I have been blowing glass since 1979.
I wanted to add something to your vast list of tools. I saw your cast puffer and thought you might like my cheap version. At most lumberyards and building supply stores you can find an almost ready made puffer in the fencing section. An aluminum fence cap makes a perfect puffer. I just drilled the end out and fitted it with a tip from an air gun (I prefer compressed air regulated to a whisper) A little bit of plumbing on the interior and you have a smooth puffer. It goes from about 1/8" in diameter to about 3".

Hope you can pass this on.
Jeff Ulrich
Loki Glassworks
Conifer, Colorado
julrich@qwest.net

I often take a heavy extension cord, like that used for air conditioners, cut it in the middle, and use it to supply and deliver power for a solid state or mechanical relay in a portable situation. This is a piece of 12 gauge extension cord surgically opened on the side and the hot (black) wire cut and stripped to fit on the terminals of a solid state relay on a heat sink. Silicon seal was added to support the wires coming out the side and to seal the cable insulation. The other end of the SSR has a phono jack which I use for connecting to controllers in a standard way. 2001-12-13

This cable is controlled by 120 VAC so that it can be plugged in to the indicator light of an element controlled by the one above, allowing control of a second element from another source instead of rewiring to 20 amp. 2005-05-10 Controllers

This double ended ladle was made up in short order when I needed to melt some lead for a weight. The two ends are steel hemispheres (2" & 3") sold at welding supply to seal ends of steel pipe. I had bought several sizes when I built the the glass gathering ball/scoop. I filed the end of the 1/2" square tubing to a curved angle to fit the side of the bowl and torch welded it in place while it sat bowl downward to be level. The lip was bent outward by heating red hot with the torch and hammering with a ball peen hammer. (click to enlarge.)

This is the scoop and gathering ball that were made at the same time, from the same kind of materials.  The scoop is a 4" end cap while the gathering ball is 2 - 1.5" caps welded to make a rough sphere, both installed on 1/2" square, 6' long steel tubing.  The scoop is used regularly for emptying my pot at the end of a session. (made back when, noted here 2004-01-03 when found not noted.)

Pipes & Punties  (2003 pipes)

The three pictures here show various views of the pipes I use, most of which I made from 1/4" IPS stainless steel water pipe (about 1/2" OD), one of which was made in the shop of a local glassblower (who does not usually sell them.)  As they stand at right, the most noticeable thing is probably how short they are, even the made one - 48" or less. I like short pipes. (Pipes I made) The shot below shows the hot end of the pipes and one made punty. The second from left is just open ended pipe while the one to the right was welded in and drilled to give more rim. The larger size of the commercial style pipe on left holds more heat and more glass per gather. To weld stainless with a torch requires a special flux to keep the surfaces clean. The punty was made by welding a piece of 3/8" rod, which most of my punties are made from, into the end of the pipe. The larger diameter makes handling more like the pipes. The punty is marked from the pipes by sawing the end at an angle as visible at right. The image at lower right shows the shaft collars applied to the pipes and punties for hanging to hold or cool. Shaft collars I have found come in a hard silver steel, like the one on the pipe and in a softer cast metal. The latter is much easier to drill out as the 3/8" water pipe is slightly larger than 1/2" (more pipes)

	These images show several stands that I have built and use while glassblowing. The one at right is my hot pipe dump and "3rd arm" for my bench. The crude box at the bottom is welded from flat sheet to hold the glass and support the arm. At left are the methods of connection of the arm and the loop that contains the pipes. The arm is bolted on using the holes that were in the hard to drill "bed steel". It is not adjustable and is at the same height as the bench. The loop is welded to an angle iron which is clamped to the upright.
	This is my yoke used at the glory hole with a shield to protect my hand. The balls are called transfer balls and can be found individually in woodworking catalogs, Grainger (in quantity) and at caster places. Woodworker's Supply index under "Rollers" 853-756 5/8" Transfer ball, $2.75 each, 853-763 1" Transfer ball $2.95 each. These have a flat flange that takes two bolts or screws. A common variation has a single bolt stud on the back. The base is sized to take the bricks used as weight. With the kind of door I have (opening from the right), I would be better served by having a track and wheels to slide the yoke left to right, but I have not needed it so far. I keep it just to the right of center of the glory hole. Bricks provide weight in base. A bed frame clamp provides vertical adjustability of the angle iron post.
	The clamp at left allows adjustment of the height of the yoke. The clamp is used on steel bed frames to lock the angle iron rails. When yokes have round pipe supports, they have a bearing for pivoting and a nut to lock the shaft collar at height. The one right is actually a spare, now being used to prop up the whirly post when it is lowered. The picture does show the post nicely (and the ragged torch cut top.) The base is a steel pipe I found at a surplus steel place when I went looking for something for this task and barely visible in the grass is the square 1/4" plate welded to the bottom.
	To the right is the stand that holds my pipes and punties just to the right of the glory hole door to preheat them from the escaping hot gases. Not easily picked out at right, a welded L of 1/2" square tubing holds the front ends of the pipes and a diagonal brace sets the angle of the arm. The detail left again shows a bed clamp. The bottom is a pipe scrap from a used steel place.

SPECIAL PUNTIES

In the traditional factory setting, specially made tools were common, especially punties designed to grab the glass after it came off the pipe. These included pronged devices for grabbing the foot of a goblet, cups for holding the bottom of a bottle, and padded blocks to fit inside a vase. Of course, these people were making dozens of the same item each day and were paid on their hourly production rate. gripper.htm

This is a special punty made to make bottles or pieces like the one shown in the pictures. Careful examination of the piece in the left picture (click for bigger) will show that it is cracked down its length half way through, probably due to lack of a long enough soak and too fast anneal. The purpose of making the punty was to work a piece like this without a punty mark. This piece was the first made and it needed more frax pushed in to make it firm, it kept squirming out. Normally such a punty would be used for uniform pieces, in production, and be fitted to the piece.
The punty was made by welding a disk to the bottom of 3" (nominal) EMT conduit. The center of the disk is drilled for a 3/8" bolt (head inside) which fits inside the 1/4" (nominal) IPS stainless steel water pipe I use for my small pipes. The bolt is long enough that it jam fits in the pipe.

This punty is fitted to the end of 1/4" standard pipe size (just over 1/2" true outside diameter) already threaded from the store. A connector, threaded all the way through, leads to an all thread nipple used in lamp making (the standard, more common, stuff is 1/8" IPS, about 3/8" OD.) The jam nuts also come from lamp supplies. The plate at the end is a plumbing floor flange, in this case not a common cast unit, which should work, but a stamped metal disk, punched through the center and tapped through inside, which allows turning it down the all thread if I wish. Having used it once, it needs another set of jam nuts, these work loose.

Not shown is a hole drilled at an angle toward the end, so a wire can be looped over the leg of a goblet base and run down the length of the pipe for a quick release or connection to a threaded rod to pull it tight. As it happens, for the piece above, I just twisted a short length of wire through the hole and around one leg, cutting it free with diagonal cutters before annealing.
Also not shown is the outer end which has been braised in and drilled to only 3/16" (4.76 mm) to center the wire.

2003 Pipes  [Earlier Pipes]

During a trip north for gravel in a rented pickup, I was near the used steel place that I get stainless from (Garland Steel) and so I stopped in even though I didn't have my torch to test.  I was looking for solid and larger tubing to make some more pipes and found marked 304 stainless tubing and unmarked solid in the same size (5/8") in a shorter 4'  piece, so I took it and it turned out to be not heat conductive.  I cut off a 17" piece of the solid and took it to the Store to use the abrasive chop saw to cut it to 4" lengths with square ends.   I made a jig to hold the rod upright by drilling in a wood block and clamped the rod with Vice-Grip pliers to hold it while I end drilled.  I could have center punched, but the holes were okay and since my drill goes in just over 2", the holes met in the center.  There are normally two choices in ends for blow pipes: 1. An end of the same metal as the pipe but thicker walls and a 1/4-5/16" (6-7mm) hole and tapering outside is welded to the end 2. A plastic, usually Delrin, mouth piece is fitted to the end usually in the same kind of metal tube for weight balance.. Most of the comments about knocking teeth out with the metal end have to do with an assistant kneeling down and blowing into the pipe whipping the head back and forth while the gaffer works the glass, inflating it against a block or pad. It is also possible to clang into one's teeth when bringing the pipe to the mouth but more rarely. The Delrin Plastic is gentler to the teeth and theoretically more sanitary if each blower has a separate tip, but almost no one does. The problem for me is that almost everyone uses their lips to center the pipe when blowing, but uses their teeth to guide the pipe and keep it from banging the lips into the teeth so the Delrin gets scarred and chews up the teeth just rotating when being used in any way. They are supposed to be smoothable with sandpaper, but I haven't had much luck getting back to original smoothness. 2007-05-09  [If buying tubing, SS comes in very thick walls, so the ends could be made from tubing with such thick walls as to leave a 1/4" hole (say 3/4" with 1/4" thick walls or 5/8" with 3/16" walls.  An alternative if buying thin and thick wall tubing is to match the ID of the thin wall to the OD of the thick wall, so the ends slip into the shaft tubing, reducing grinding but leaving a slight step a few inches from the end. Punties often have such a step to have a bigger grip on a smaller end,  as here] 2006-10-24

I chose the ends with the most centered holes to be the outer end and ground the other ends to fit inside the tubing.  In order to do the grinding, I built the jig shown from 2" of 1-1/2" 16 gauge tubing, a pair of 1-3/8" x 5/8" ID wheelbarrow replacement bearings, a piece of 1x4 lumber and a 5/8" ID shaft collar.  A machine screw bolts the tubing through the wood to a T-nut accessed with the larger hole on top (the two holes on the side are tapped, but not used in this version.)  The rod slides into the bearing and almost emerges from the other side; the shaft collar prevents the rod from moving further.  On my homebuilt grinding wheel head, I added a platform so I could lay this wood and line up with the wheel.  I used a coarse wheel to grind the ends to reduce their size, as shown on the pipe end at an angle.  The hidden end of the other piece looks the same.  I used heavy leather work gloves to control the rate of spin that the grinder gave to the rod.  I tried the reduced end in the pipe as I worked.  The mouth piece was rough ground at an angle and then a finer grinding wheel was mounted to smooth the outside. 2003-01-19

Next, I will weld the ends in place.  I have stainless steel rod and somewhere I have protective flux from building the ones above, but I confess, I can't recall seeing it for some time.  Torch welding of stainless is less easy than MIG and I am almost tempted to rent a MIG to try it out. 2003-01-19   After several days of intense searching, which were constructive because I gained a lot of moving around space in the garage/shop and threw out a bunch of stuff, I alternated between "logically" looking where chemicals were kept vs. where welding supplies were kept vs. where glass supplies were kept.  The last proved rewarding because with the grinding grit in the bottom of a 5 gallon plastic bucket (one of about seventy with stuff in them) was a rusting can of Solar Flux B for stainless steel, last used to weld over the tips of a couple of pipes and insert a punty tip. (above)  The rust seemed to go most of the way through, but the powder inside was dry and fluffy and the instructions barely readable.  I typed them off and visited the web site. "If you weld stainless steel you'll love Solar Flux"  I transferred the powder to a tough plastic bottle with a copy of the directions.   I got out the threading rig I built and plopped it on my outdoor work bench, took up the tubing and ends, buttered on the flux (which is mixed with methanol), fitted the ends carefully, tapping them to straighten them.  The Solar site calls for a carburizing flame (gas rich) and I found that works well.  This stainless does not conduct heat well, therefore it gets very hot locally very quick. This means the metal gets molten and flows/drips.  The flux helps contain the flow, but I still had to do some torch repair work and then ground the welds.  Before I put the welding rig up for the night, I cut braces for the glass garage as it wobbled a bit much and welded them, welded a riser on the frame for the peak of the roof to hold whirlies and ground down another 4" piece for a matching punty and welded that in place. 2003-01-30 At the right you can see the moderately rough result of the grinding with no attempt to clean off the flux, etc.  The outer diameter of the pipes is uniform (no bumps) although some pits remain.  I used the pipe and punty for a blowing session and was pleased with the result. Being careful to make them straight was important.  I shall make at least one more of each, perhaps more. 2003-02-08  I did make another pair of pipe and punty and the welding on the pipe went particularly poorly.  In fact, when ground smooth, there were holes at both ends that leaked air.  Rather than arguing with the welding, I put the pipe aside until I had some other braising to do and repaired it with brass, today. 2005-05-13

Email Reply on pipes No, I don't sell (at least at this time). The directions for making pipes and punties include a way of making without fine machining, but torch welding SS is difficult. If you have to deal with minimal purchases (like some SS metal suppliers want $150 min.) you can use up a minimum real quick with a couple of tubes of thick wall and thin wall tubing. You can save a lot of money (at $100 a pipe) and get what you like. The shaft of pipes is 1/16" wall mostly (.0625") so if you buy 3/4" tubing with 1/16" wall and with 1/4" wall for the ends. You want 300 series SS, usually 303, although Steinert http://www.steinertindustries.com/  uses 309 for the head and 304 for the shaft. See http://users.ticnet.com/mikefirth/stainles.htm#SHOP  If you want to make larger shaft punties with largish heads, you can buy some 5/8" solid which will slide inside the 3/4" tube and be welded without machining. If you have a TIG or MIG welder, you can do better welding than I can. If not, talk to a welding shop and see if they can butt weld the tubing. If they can, then the only machining will be to taper the mouth piece. If not, then the other end of the mouth piece and one end of the hot tip will have to be reduced by 1/16" (to 5/8" dia) for about 5/8-3/4" to slide fit in the tubing. Get a quote from a machine shop. See my page above for grinding. I like 6" pieces for the ends, so the person/shop that tapers the mouth pieces can saw the thick wall tubing into 24 blanks (assuming a 12' piece cut slightly short of 6" each). See below on how many get machined. Be sure understand what you like in the length of a pipe. Many commercial pipes are 52", 54" or longer. Steinert does not mention the length of their pipes but they do say their punties are 54" I like mine shorter because one technique I use is to blow down onto a wooden or metal plate and I am 6'2".  I could use a step up. Depending on how the ends are attached, the tubing is 11-12" shorter than the length of the pipe. I would, if paying someone to weld, make up 2 pipes and 2 punties, and check for balance and length, before cutting the rest of the tubing. Since I ground my ends, I made 2 pair at a time. Ask a machine shop about savings on quantity if you are sure of the size. It may be they can setup and do all 24 slide fits on one end (cut 0.063) for less than doing 4 or 6 at a time. Note that you could do this, have only a couple tapered and come back to do some more once you were sure of the fit. You do want the tapered area smooth (almost polished) and you want the mouth end blunt with a slight curve to take off the corner (i.e. the final diameter should be about 3/8" so the wall is 1/16" around the 1/4" hole. see drawing.) Heck, I've been looking at what I have written and deciding to use it on a page, so I have taken time to do a drawing. Please note that I do put a shaft collar on my pipes and punties - the same distance from the hot end no matter what their overall length for even hanging in the garage, etc. I do not use a rubber hose grip, which I might need if making bigger pieces, but that I don't much like. A grip adds weight (good) to the mouth end and thus affects balance.  I do not texture my grip area (some brands do) but I also do not polish it. I do not like plastic mouth pieces, I actively favor metal. Best of luck. Mike Firth

This is the grinder setup I built, which uses the motor from the glass grinder.  There is nothing too original about it, except for some details.  The basic grinder is two oiled bearing pillow blocks mounted to a board with a 1/2" shaft with a pulley on one end and a shaft adaptor for threaded mounting of grinding wheels on the other.  Clamped in the vise it has been used for years, see the patina on the wood.  When I began grinding for the pipes, I added a couple of spaces and the board platform and another spacer sized board below, to clamp in the vise as shown, with bolts through all.   Also, below and right below, is the pipe end grinding jig in place on the platform.  Right is a shot of the blade grinding jig with a more horizontal view inset.  The spacers lift the blade almost to the centerline of the wheel, while the slight backset of the red piece gives a ledge to set the back of the blade on.

I wanted to have a pipe heater and hot bit holder and maybe even a color pre-heater, with a range of temperatures. So I dug out an old venturi burner I bought before I realized how much heat I needed for glass. I found piece of broken kiln shelf and squared off the sides. I picked out three pieces of foam from what I had collected on occasion. On one of the pieces I carved a port the size of the burner interior. On another, I cut an angle to be an exit port. I carved the third to curve heat around the inside.
I used wood glue to laminate the foam to the kiln shelf and each other with the shelf sticking out the sides a half inch all the way around. I then clamped up a frame to put about 1.25" of space all the way round. I mixed a fairly stiff Insulating Refractory Castable (IRC) to form the back wall and let it set for a while. Then I mixed a fairly sloppy mix and poured it in and pushed the form into it, imbedding the shelf in the back wall. I then mixed a moderately sloppy mix and filled in around the foam, especially under the angle and above the burner port. Finally, I made a stiff mix again to build up the front to support the corners of the kiln shelf. Keeping it moist, I let it set overnight, then took the form off and let it dry for a couple of days in the Texas sun. Then I hooked up a torch and burned out the foam (smoky), and hooked up the burner and did a first heat. Should have rodded the mix more, there is a distinct seam/crack part way down. Still to do: a mount for the burner, frax board under, maybe a metal shell and frax blanket around, depending how hot it gets. I don't want it too hot.
This is a view of the unit after the first test firing. Steel angle forms a support at the bottom, framing a 1/2" frax board. A lump of castable supports the hot end of the burner and a tapped hole on the burner takes a bolt through square tubing to hold the burner level and in place. [The material is not very strong and when a punty stuck to the shelf and was jerked to get it free, the front half of the top broke off down to the shelf.  It looks repairable, though not done yet. 2003-04-03]

These small crucibles were prepared so I could melt small amounts of color, perhaps by floating them in other melted glass. They were made from #1 potters clay [grey] and the crucible mix I use for bigger pots. The clay pots were made inside a glass custard cup and I consider them to be an accidental success, on one set the clay stuck to the glass and the inside dried while the outside stayed wet, so the inside cracked. So I mixed up a batch of plaster of Paris, lined a bread pan with aluminum foil, oiled the outside of the custard cups, and sunk them in the liquid plaster by adding water to weight them. The plaster, traditional mold making material of potters, sucks water out of the clay, so it shrinks from the outside, pulling in from the mold and drying hard. 2002-07-13  Two of the pots, one of each kind have been in the glory hole for several firings and seem to be holding up well, on with color and one with clear. 2003-02-13 Mini-Firehole

I wanted to do some pure clear and pure color so I built a pair of clay boats for the bottom of the glory hole, rolling the white clay as above, and pressing it into half pieces of white 3" PVC conduit and then adding the end pieces.  Pre-fired in the annealer to about 1500F  Shown in the glory hole after first use with excess glass scooped out before cooling. 2004-01-30

Pi-Divider
The purpose of pi-dividers is to lay out a straight stretch the same length as the circumference of a given diameter, as when laying out Murrini to be picked up.  I decided to use making a pi-divider as a project in casting.  But after making a clay model and rubber and plaster molds and casting a pair of wax positives, I realized that the detail work I was about to do was far more than was needed to make the tools.
My original plan was to match the sketch used to define Pi Dividers in the Tool Glossary (right) with cast aluminum jaws and aluminum bar stock for the straights. But when I began looking at fitting the bar to the curve and checking the curve I really needed, I found that I could use wider bar stock and cut the shape just from the flat.

  This drawing shows the revised plan. The dimensions used were selected first to accommodate the largest diameter I expected to use - 5" - at which point these dividers will be open at 60 degrees. Pi (3.14159... ) times 5 is 15.708) The radius of the arc (2-7/8") was chosen to be larger than the radius of the 5" tube to provide clearance - straight lines from a diameter will pass through the edge of the piece.  The location of the center of the arc was chosen to leave enough material above the arc for strength and to give good form to the tip.
  On a piece of 1-1/2" x 1/8" aluminum bar stock, three critical center points and a couple of lines are laid out.  One point is punched 1/4" up and 1/8" in from the left lower corner. This offset gets the pivot point up from the edge of the bar stock for strength.  From this point an arc equal to the diameter element (5" here) is swung.  From this line an approximate measurement of the circumference is laid out (say 15.75 inches in this case) ending 1/8" below the upper side.  The location is punched.  A straight line is drawn between the punches.  Where the straight line crosses the 5" arc, a third punch is made.  Where the 5" arc crosses the lower edge is now used to draw a line diagonally up to the right, through the right hand punch and off the edge. The bar stock is cut with a saber saw along this line, which leaves a long point attached to the remaining bar stock which becomes part of the other half.
  A compass is set to 2-7/8", the bar is held down and lining up the pivot of the compass on a line 1-7/8" below the edge of the stock so that the arc passes through the left hand punch, an arc is drawn as shown.  The saw is then used to cut the arc.  This piece is then used to lay out the other piece, aligning the tapering tails, which with proper planning has already been cut in making the diagonal saw cut..
 Once cut out, the two pieces are carefully aligned and using the punch on the 5" arc, a 3/16" hole is drilled.  Before the pieces are turned over, a 3/16" bolt is inserted.  At this point, the distance from the center of the bolt out the taper is carefully measured and the tips are cut off just a shade long - say 1/16".   Now the bolt is removed, the pieces turned over and the bolt reinserted to be the pivot.  Now the tips must be carefully filed, remembering that taking too much off makes life difficult. 
  The tips of the tapered legs are filed to bring them even closer to the desired length.  The tips at the curve are carefully shaped so the legs draw together.  The ends at the arc is gently bent sideways to bring the tips into better conjunction.  As filing is done, the tips are slightly beveled to form a better defined contact point, keeping the distance from the pivot carefully in place.  When done the legs should close just at the tip while the arcs just touch.

I came up with the idea of preheating blanks in the annealer and transferring them to my smaller box to be laid on a mold and taken quickly up to sagging temp, then brought down to annealing or a stiff temp and moved back to the annealer.   Obviously to do this I need a way of handling the blanks, so when I had the torch hot, I cut some stock and drilled it, then bent a matching pair. (When making tongs, the bends are identical, not opposite, as noted in a blacksmith book - it saves thinking.)  The handles were bent to be a thumb and edge of hand in gloves grip and were actually re-bent a couple of times for size.  After the picture was taken, the tips were wrapped with frax and a couple of wraps of wire added to keep it in place. 2003-02-13  In April, after a couple of uses, drilled another pivot hole closer to the handle so a small movement, especially with gloves, opens the jaws wider. (right) 04-25

Glued Wood

The items to the right were glued up with Gorilla Glue and then soaked as wood tools for glass commonly are.
  The tongs are for shaping the basic form of a bottle neck.  The dowel is screwed to the aluminum tong arm, but the cup portion is simply glued to the slightly roughened aluminum.  The white material is where the GG has foamed out of the joint.  For GG to set it requires humidity and ideally a film of water on at least one of the surface.   This made it a candidate for this project and so far it seems to work fine.  The tool shown has been soaking for about 2 weeks.

When I decided to make a steam stick from the model used by Fritz Dreisbach, I tried to find a small ricer pestle, but several shops only had large ones.  So I drilled a chunk of cherry to take a rod and supported it on both ends in my drill press and carved and rasped it down to a cone shape - the center portion of the lower unit shown.  Because of the drilled hole and rod, I could not turn it down to a point and I needed a handle.   So I turned a small cone, held directly in the chuck jaws, from cherry dowel I had purchased and counter drilled both ends of the center to match.   I used GG to assemble the handle and the cone to the center.  It has been soaking for about a month.  Of course, the cone structure does not require the glue to do as much as the other piece. 2003-09-24

HOSE - A hose that fits on a pipe is very convenient when working alone as it allows blowing against a pad or block while the pipe is horizontal (as opposed to blowing with the pipe raised or lowered from the mouth.)  It takes a bit of practice to keep the hose from tangling while maneuvering and a swivel really helps.  Commercial versions for pipes are available [$31 http://steinertindustries.com/osc/product_info.php?products_id=139 with the unfortunate proviso that you have to match the size of the pipe.  I had two different sizes and expected to get more (and did.)   So I bought my hose, mouthpiece, and swivel from Wale Apparatus. http://www.waleapparatus.com/index.asp?category=18702    I bought the whole thing ($21.95 now, first item on the page) with angle swivel, hose, and mouth piece. The hose sold is surgical rubber which is very soft.  It deteriorates.  I replaced mine with clear vinyl tubing. (F)
My unit, with 1/4" barbs on the swivel, was sold without a cup, since a piece of the rubber tubing is used to fit to glass tubing for lamp work.  To adapt the swivel, I bought several short pieces of clear vinyl tubing in several diameters from the hardware store and after cutting them to size, fitted them inside each other to make a cup to fit over the end of pipe mouthpiece. (A) shows two short smaller pieces (about 1") fitted inside each other and a longer (about 2.5") larger piece.  The ID of the smallest is 1/4" and of the largest is 1/2", with the middle piece being 3/8" and the walls all 1/16".  As shown (B), the turning barb on the swivel is fitted in the inner piece and then all three are pushed flush (C), the slightly large barb expanding all the tubings against each other. A look (D) down inside the cup shows the space.  A close-up (E) and longer view (G) of the cup on the pipe mouth piece as well as the two pieces (F) - hose with mouthpiece and swivel and the cup - are shown. (Click on picture for double sized - hold Ctrl while clicking to open larger in new window.)
When working, I take a turn around my neck, leaving a short length to the mouthpiece so it hangs about nipple level when the mouth piece is dropped.  Like a tobacco pipe mouth piece, which it resembles, it is gripped in the teeth while working.  The long length is draped over the arm (some people put the surgical rubber inside their shirt sleeve) and slid over the pipe end.  When the pipe is put up, the hose stays on the shoulders rather than being left hanging on the hot pipe.  The right angle swivel is better than a straight swivel, especially with the weight of vinyl tubing, which puts a lot of drag weight on the pipe, tending to pull the cup off the pipe or the hose off the swivel. 2008-09-09

CRIMP - A crimp, in furnace working vocabulary is a tool for making the shape of a rose in glass.  Most notably, several glassblowers in New Jersey made the Millville Rose.  My first crimp was thin brass sheet and about 3/4 inch in diameter.  The thinness melted when I used it.  E-mailing Wheaton Village gave me the info that theirs were 1-1/2 to 2".  So I made a new crimp.

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