Top layer curls on the deep and the dammed

[Paul Tarlow]

I fused 4 3mm layers together at the same time I kiln-carved the bottom. The edges of the top layer "stuck" to the fiber paper that lined the dam.



This isn't the first time this has happened to me. I can fix it but would appreciate thoughts on how to avoid it in the first place.

Thanks,
Paul

[Brock]

Try making the dam a little bit bigger, maybe an 1/8", or less, all around, than the glass. That will allow the glass to flow out, and down to the sides of the mold. Or, get a wet belt sander. Brock

[Ron Coleman]

Paul

I think the secret to firing against a fiber paper dam or kiln washed dam, is to keep the top layers of glass away from the dam by cutting them undersize. You want the glass to flow up to the dam material and not try to slide down as it melts. You could get the same effect by cutting them all smaller and letting the whole stack of glass move out against the fiber. Notice I could have said "dam fiber".

In the Bullseye tech note about firing deep they show using clear irid glass to border the piece. This can only be done if the piece has straight sides, not round.

Ron

[Paul Tarlow]

Thanks Brock and Ron - makes perfect sense.