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There is a crack that is only on the top layer of my 14" platter. It is healed and soft. Not through the second layer. It also did not crack through the design on the piece. Why would this occur. It is. Small squiggle shape. Not n S or a c shape. It appears that it cracked and then fused together but it is visible. Can it be fixed and how. Also anyone gues as to why?

Can you post a picture?

I have been trying to upload a pic. How do I do that. Help

Sounds to me like too rapid heating on the rise. The glass may have softened at edges and strain became too much for the top layer so splitting.

I think your correct and this happenned on a piece a while back. It actually had a large crack on the top layer with soft edges. Very cool looking actually, I put it in my gallery and it actually sold quickly!

For this piece I did go faster, I began at 450 dph and that is a schedule I use for small pieces. This is a larger 13" platter with a few design elements. A tack/ contour fuse. I did another at 200dph and a 3 hr anneal. Hope to open the kiln and find a good piece.

Thank you for the input

Don't know but curious....would the piece with the large crack that sold quickly possibly have been subjected to some annealing issues and may be in danger of causing a spontaneous ( or not so spontaneous if it's built in) break in its future? Have no idea but am curious to know if it's at risk or would the fact that it cracked have alleviated the stress? Jen

I agree with Stephen. It cracked during the heatup, opened when it got hotter, and healed in the big heat. Slow down your initial heatup. The piece is now structurally sound, assuming a good anneal cycle happened. Visually, is your call...