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hi guys ,it's that crazy kiwi back again,with more questions,,I want to try and make a patten bar in a s/s tube standing on it's end the tube is 42 mm wide and 12 cm long. packed with stringers then packed again with fine frit ,yes I know I will get air bubbles .i have 1/8th fiberpaper lining the tube. The questions I have are . should I treat the glass as as solid hump of glass in the heating of the glass to a full fuse,it is very well pack.how long should i hold at top temperature and what sort of annealing would I be looking at . if someone would like to work out a program I would be very grateful. I will be using my Paragon high fire kiln which has 8 segment programs the glass is coe96 spectrum . any advise would be great

you can heat it afap. it isn't solid yet, and even if it does crack, do you care? it's going to move inside the tube when it gets soft anyway.

since it's packed so well, you will have to hold at the top temp a long time to ensure that the heat reaches the middle. treat it like a 45mm thick casting for annealing.

I put our round pattern bar formers on end like this in every full fuse. No special temps are needed. They shink in height around 25%. If you spray the 1/8" fiber paper with MR97 before loading it the glass will slide easier with no spikes!

hi guys ,,thanks for the info ,,

I just bough two 4"OD SS Tubes 6'' each for 25.00 each- cant wait to try this !

All you need is a plain old stainless steel pipe--nothing special, although you want to make sure you've got a stainless that will stand up to heat without spalling (not all will). I like to line it with two sheets of 1/16" or 1/18" fiber paper, cut precisely to fit, then staggered so the seams are in different places.

They'll generally stand up on their own without leakage. To be on the safe side with heavier cane, I line the pipe with fiber paper, then stick the bottom of the pipe in about a half-inch of refractory plaster (plaster of paris would probably work as well) in a cup or small tub, let it set. That both seals the bottom and gives a more stable base, making it a little easier to pack--nothing falls out when you lift up the pipe to put it in the kiln. The base also seems to make it a bit easier to slide stuff out of the pipe after firing--just whack the top of the base with a hammer and the whole thing usually slides out. If it doesn't, slip a second, slightly smaller diameter pipe (or dowel) in the pipe to the glass, and give it a few taps with a hammer. That way it pushes the glass out very evenly; if you push more on one side of the cylinder than the other it can skew the glass in the pipe and get it stuck.

I think Laurie's a bit optimistic on the shrinking--it depends on what kind of glass you're using and how tightly you've packed. (BTW, be careful about packing TOO tightly--you can tear the fiber paper, opening it up to the metal pipe). I've been doing pipe cane for a bit more than a decade, and overall I'd say my shrinkage averages closer to one-third. It can go up to 50% with longer, wider pipes where frit is a principal packing material.

Program-wise, I go up pretty fast (300-500dph) to a bubble squeeze, and hold the squeeze for an hour or so, to give the components a little more time to settle and push air out to the fiber paper.

I tend to process mine for 2-4 hours at top temp, although you don't need that long; I just like it because the glasses start flowing a little bit and makes more interesting patterns. I anneal for the full outside diameter of the pipe. So if the OD of the pipe is 42mm, anneal as for a 42mm casting.

The way we pack ours they shrink around 25%! I love your idea anout the plaster for the base! We are doing some 12" pipe that I have been putting kiln stilts around or a few wired together with nichrome wire.

Thank you so much for posting this! For a larger pipe that's going to have about 3.25 inches of glass in it- how long should I hold it at the top temp?

Really appreciate your post!

hey thanks for the info Morgainica,,i fired my tubes and was very happy with what i got out ,some interesting points for any one trying these
the tubes i had pack with just strips of glass,(6mm) i got no air bubbles, the ones which had strips and fine frit (well packed with a few taps on the side) had a lot of small bubbles
i gave them a long bubble squeeze 1.5 hours and a 2 hour hold at 820C
all in all i was quite happy . i have cut them in to 6 mm slice's

Any photos?