Bubbles with the new Bullseye fiber paper

[Stuart Clayman]

This was a process that we have been doing for years. The only difference is the new Bullseye sheets.

Shelf is coated. Then covered with the new paper. Single sheet of thin bullseye covered with strips of glass with frit between the strips. Bubbles have happened on multiple firings.

Has anyone else had this problem with the new sheets?

[Paul Tarlow]

This was a process that we have been doing for years. The only difference is the new Bullseye sheets.

Shelf is coated. Then covered with the new paper. Single sheet of thin bullseye covered with strips of glass with frit between the strips. Bubbles have happened on multiple firings.

Has anyone else had this problem with the new sheets?

If you still have some old thin fire you might want to try a side-by-side test. I was sure that the new stuff was causing brown spots. Same deal -- I was sure the only thing that had changed was the new paper.

I did a side by side and found it had nothing to do with the new paper -- the change to which just ended up being coincidental with some other stuff happening in the studio.

I've been doing lots of frit-on-single sheet-on new thin fire without any bubbles.

- Paul

[Elizabeth]

I have a piece annealing right now...first time firing with the new paper....bubbles all over it. Double Spectrum baroque glass. 1450 degrees F; 20 minute soak; 45 minute anneal at 925 degrees; hold at 700 degrees; 10 hour cooling. What did I do wrong? (I've never fused Spectrum before.)

[robertb]

How quickly did you go to 1450? The baroque has lots of waves which can trap air for bubble growth.

[Stuart Clayman]

Problem solved.......

The new paper is flatter and seems to be firing things hotter. We slowed the ramp up to allow for the air to escape. We were only getting the bubble in the kiln that fires the fastest of the ones we have. The thought is that since the paper is flatter (and may more dense), and the kiln ramps up fast it was traping air where it was not happening in the slower kilns. The reason that I said that they items seem to be firing hotter is that we are using the same program settings that we have been using for years and with the new paper it looks like the thin items that we are making are cooking a little more.

So, the solution, for this kiln only, is to slow the ramp up speed, lower the temp, and lengthen the hold time.

Stuart