Hans Paijmans wrote:

nJb wrote:
Hans,

The pics make it clear enough, thanks. I just wanted to see what you
meant by the pot in the bottom. Interesting concept. I helped build a
small pot furnace and glory hole last summer but had never heard of the
two combined into one.

Neither did we :-)

A few minutes ago we opened the annealing oven for the latest
batch, and it is instructive to see how the quality of the
glass improves with the time that the pot was heated. The
last few pieces (after the furnace had been heated for five
or six hours, were of rather good quality, with bubbles so small
that they were almost invisible.

The flaking of the fiber causes my wife (who is the artist, I am
just the mechanic) some worries. We sprayed it with waterglass
before the first firing up of the oven, perhaps should not have
done that. Or perhaps it is an inevitable byproduct of the
rapid heating and cooling.

That would be a pity, because the pot (although broken) keeps
very well.

I would suggest colloidal silica instead of waterglass. We had a thread
about that when I built my kiln last year. One trade name is Kaowool
Rigidizer, made just for what you're doing. Also, using the pleated
process for lining the glory hole reduces loose fiber.

Pot heat time is a definite factor for small bubbles. That is why many
small tanks are electric and kept on continuously. That way they have a
lag time between charging and blowing. At least this is the way I
understand it.
--
Jack


http://photos.yahoo.com/bc/xmissionbobo/