Corin Anderson (magellanic) wrote,
Corin Anderson
magellanic

Continuing techniques in flameworking

Melinda and I joined Greg and Becca at The Crucible this weekend for a two-day intensive workshop on glass flameworking. "Continuing techniques" meant to follow the intro course that we all took, the class spent most of its time on working with glass tubing rather than solid rods. Our raw materials: 22.5mm heavy wall clear; 30mm contrex, which has internal ribs to give nice longitudinal lines, and 22.5mm heavy wall cobalt, which, being cobalt, is stiffer to work and a bit shocky but rewards you by showing exactly where the glass is hot.

We started Saturday with learning to pull points and make blanks. Pulling a point means heating up 2" of the closed end of tubing, attaching a punty, and pulling when its a modest orange. The result is, for the 22.5mm tubing, about 18" of 1/4" tubing now at the end of your big tubing. Burn off the punty. You need to open up the end now, and we tried two ways. One is to heat a small gather, make a maria, then knock it off with tweezers. A second is to use diamond shears to cut the warm bit of glass off. In Doug Remschneider's DVD he shows just letting it cool then scoring it with a glass cutter. In all cases, you then need to flame polish the end. The goal of making the point is to have a hollow tube for a handle through which you'll later blow to shape the glass.

A blank is a length of tubing, maybe 3-6", with points on either side. One point should be closed so when you blow in the other end you can shape the hot glass.

I'd have been happy pulling points for a few hours, to work at it and to make a bunch, but we had only 45 minutes to do this, and I managed to produce only three or so (Jay had optimistically said we should make 15), in between failing to work the Contrex correctly (it's thinner than it looks, due to the ribs) and moving my car (2 hour parking in front of the Crucible on Saturdays -- that's new).

Jay showed some other techniques. Feathering: apply a thin stringer around a blank in a long long spiral. Then, paint a 6mm clear row down the length of the blank and you'll end up pulling the stringers along. Pretty . There's lots to work out with heating and condensing the glass, and applying that long spiral is magic (touch the blank then hold it above the flame, turning it as you feed the very thin hair of color along). I tried this technique twice but didn't succeed. I'll practice it later, and on solid rod (no need to waste blanks). Also, a common trick to make goblets look interesting is to twist them. Eg, lay on a bunch of thin lines of color longitudinally, then twist the blank to make a nice swirl.

Okay, now, about blowing. To make a round bubble, heat a section of the blank until it's soft -- on the orange side of the pink/orange transition. Always turning, blow a little to enlarge the bubble, and push the handles together a little. You can reheat it in order to blow it again, but don't go more than about twice the original diameter lest you blow it too thin. It's pretty important to keep the handles on center with the blank. To center, heat the shoulder (the part of the blank that's just before it tapers to the handle) and move the handle laterally. The taper may no longer be pretty but it's on center, and that's what counts.


Removing the blow tube. Suppose you have a bottle and want to remove the blow tube. One way is to heat part of the neck, blow really thin, put a thin part in the flame then blow a little. It'll clear out and you can tear the glass off from there. A second way: heat the body of the bottle to fill it with hot gas. Close off the neck where you want it, but then immediately tear away the glass, with the handle you're removing, until you clear open the hole. The hot gas in the bottle will cause it to want to expand and blow out the bubble. Focus the heat right on the end where you want the hole to appear. [I'm not sure I understand the physics here: if I heated the bubble earlier but have removed the heat, wouldn't it want to draw in?]


For the day I made maybe 5 artifacts. A couple of small bottles (twisting contrex, trying the feathering technique, etc.) but nothing great. I decided to focus on practicing technique rather than making any one thing amazing. Milon Townsend's chapter on creativity would suggest this is a good strategy: don't focus on making the current project perfect, focus on how to make the next piece better. On Sunday Tara gave the opposite advice, which I obviously don't agree with: make every piece your very best; you owe it to those people who taught you the technique. I disagree because I simply can't make a perfect goblet on my first try, and obsessing over imperfections will lead to ignoring the overall principles I should be learning. But I digress...


I spent most of my Saturday working with the clear tubing, not the contrex or cobalt. I tried cobalt a little but because it's shocky, you need to heat it up gradually, which is slow, and you need to do this every time you pick up a cold piece of cobalt, and I the source tube was heavy (about 30" of 22.5mm tube). I tried the contrex a bit but it's tricky to work with: it becomes very soft suddenly. The obvious visual trick to try with contrex is to twist the glass, but I would seem to always end up with folds as I did so. It's something I need to practice, and because I didn't think I'd learn much by practicing it with Jay and Tara around I put it aside in favor of the simpler material.


Sunday we spent one third of the time making fluted feet and the other two thirds making a three-part project (any three parts would do; Jay just asked that we make some compound project). A fluted foot starts life as a bubble, maybe 2-2.5" in diameter. Make a maria on one end then remove the point on the other. With a small hole open on that end, use a reamer to coax the lip a little bigger. Heat the rim and bell thoroughly and spin rapidly (well, maybe 2x your normal rotation speed) in order to throw open the hole wider. If the lip is still not open all the way you may need to work the lip open with the reamer. When working with the reamer you can and should turn slowly, not fast. You're using the reamer to work the glass, not centrifugal forces. Use a large reamer, place the end in the center of the foot, and gradually rotate the reamer to be as square against the center line of the foot as you want. You should be applying heat in the lip and bell of the the glass, inside and out, and not on the tool. (The graphite can withstand it but it doesn't help. And, hot graphite *will* stick to glass, as I found out...)


Oh, about heat. Melinda and I have been using pretty small flames, as far as boro work goes: the white candles are maybe an inch long. Jon at Temperchi even once commented how he was surprised how small of flames we used. Today was very different: everyone was using *big* flames: the candles were 2-3" and you could heat the gas hissing out the torch. We also used a more reducing flame, to be a softer, bushier, flame, and these flames would have 4-5" candles. Big heat. Makes glass melt very fast. But also means you can't get closer than about 4" to the flame without getting your fingers very hot.


I managed to make the first fluted first after the demo, and a very good one at that, and Jay and Tara were impressed. I followed this up with a sequence of 4 or 5 much worse feet. I still would put them in the kiln (remember to have the long punty on the end so you can take it back out), but by afternoon the kiln was getting pretty full. For my compound project I elected to make something very simple, with the plan to make _something_ rather than nothing at all. A simple bottle, which Jay suggested I turn into a more open bowl (and it was a great suggestion -- looks much better this way), a small marble (I used the mold, not just gravity), and my first foot. Jay helped with the assembly dance: extract the foot and marble from kiln; grab the foot with fingers tool; remove its punty; attach the marble and its punty; remove the marble's punty; get the bottle from the kiln (with blow tube still attached); attach to marble. When attaching each piece, heat up each bit to attach to make a good hot seal. Use a small flame. It was important than I leave the blow tube on the bottle, in order to have a handle for this assembly. In the end the goblet looks sorta nice.

I decided to make a second one. Well, in fact, I decided to make just a bottle but using frit. Amazon bronze looked nice. I made a blank, heated, rolled in frit, condensed, then blew out a bottle. I left the blow tube on and put it in the kiln. I made a second one, this time, planning to just make a bottle. I flared open the top, but as I was finishing the bottom, Jay suggested I make it into a goblet, too. With 15 minutes left I made a small marble with some bits of frit (again, Amazon bronze), then had Tara help me assemble this piece. Marble and foot first, but using the really ugly foot because it was the only one I knew was mine in the kiln (I had others that looked much nicer but didn't recall which were mine. oh well.). Then the bottle. Tara couldn't get the fingers to close on the bottle (weird, because I managed to do so, maybe using a different fingers tool) so used some other, older, more gross tool that was sorta shaky. We managed to get everything assembled, and even mostly upright, although with the folded fluted foot it's a site to behold. Heh.

And that was that. The key things I want to remember are:


  • Pulling points and making blanks. These are useful things and I should make a bunch.
  • Heavy wall tubing is The Thing to Use.
  • Making a hole in a tube: heat a patch, blow in the end with the patch in the flame.
  • Making a hole in a closed bubble: heat the bubble to increase pressure, then heat where you want the hole to appear. Tear the glass there to make the hole.
  • Compound projects aren't so impossible. Garage work and use fingers tool to hold things.
  • Centering your handles on blanks really does make a big difference.


Now got to get to Temperchi to get in some practice.
Tags: fire arts
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