Bubbles and Fiber paper

[Amy Jakowski]

Never had this happen before to me. Did the fiber paper insulate the glass so it didn't fuse well? But why the totally regular, evenly spaced small holes on the edge?
Firing schedule
250 500 30 min
250 1150 30 min
100 1250 30 min
400 1480 10 min
400 1500 10 min
400 950 90 min
100 800 10 min
200 700 0 hold
Side and top elements. Jen Ken 24' x 24' kiln
Big holes under opal circle that did not break thru.

[JestersBaubles]

The evenly-space small holes are due to the layup of the glass. Those "notches" are the perfect place to trap air and cause a bubble.

Dana W.

[Amy Jakowski]

The notches are next to the kiln shelf and the holes are in the top glass layer farthest from the fiber. Open holes towards kiln elements. So this air is trapped??
No way to squeeze them out?

[Brad Walker]

As Dana said, it's trapped air, caught in the spaces created by the fiber paper underneath.

Easy solution, just takes two firings -- first, pre-fuse the layers of glass together on a flat shelf, then fire a second time on top of the fiber paper.

[Amy Jakowski]

Thank you. Two firings sounds excellent.

[Buttercup]

I like them! Could you reliably replicate that effect? jen