nJb wrote:
On Mon, 8 Jun 2009 00:09:38 -0700 (PDT), Permafacture
wrote:

I was thinking about how to slump a large diameter tube from a flat
plane of glass. I have little experience with glass working and dont
know to what degree this is workable...

You'd take a piece of float glass, from like a window and slump it
over a ceramic tube you made/found as a form. Put it in the kiln and
let it soften and after its really gooy pull it out for a second and
use poles to roll the hanging edges together. The maybe flip it so
the seam is on top and put it back in the kiln.

Good luck. With a lot of practice you might pull it off. Most likely
you will wind up with a big mess and some burns.
?

Is this at all how you would form a large diameter tube from found
resources?

No, I would either blow it (not likely to be called a tube), have it
blown, or buy it from a lab glass manufacturer.


What size kiln do glass workers usually have; what is the widest sheet
i might be able to work?

I have a 3x5' and a 4x8' but I wouldn't even try to slump a tube.


can it be anealed in the same kiln it was slumped in?

Yes.


Jack
thanks!http://www.lambertsglas.de/

The link below

http://www.lambertsglas.de/
has a video how big tubes are made.

Slumping over ceramics: The glass contracts more than ceramics while
cooling,
so it will break or at least press itself permanently around the ceramics.
Steel tube with a separator is better.

-lauri