GAH! Why is this happening???

[glassiquegirl]

This has not happened to me before.  I don't know why, so maybe someone has an opinion.  I fused this piece using my normal schedule, all glass is system96, I use a Jen-Ken Fuse It (9 x 9 x 4).  If you look closely at the pic, you can see a crack that occurred sometime during the fusing process, only on the blue layer.  The blue is layered on top of a mint green base.  The pink layer has a layer of thin clear on which the poodle image is painted.  The squares of spirit are not capped, except for the pink dots.  The crack ended up fusing together, so it probably happened during my ramp, which I have even slowed down just a bit.  1100 degrees, 350-400 degrees per hour, hold 15 minutes; 1250 degrees, 150 degrees per hour, hold 45 minutes; AFAP 1450 degrees, 25-30 minutes; crash to 900, hold 45 minutes; turn kiln off and leave it.

Any ideas?

[Stephen Richard]

You have uneven thickness of glass at the start (1.5 layers and 3 layers)  This needs more care in heating up.  The fractures did not move apart, showing that you are only a little above the permissible rate of advance.  But I would slow to no more than 150C per hour.
You have no annealing cool.  It is not sufficient to turn the kiln off after the anneal soak.  You need to control the anneal cool to at least 370C - 110C below your turn off.

[glassiquegirl]

Thank you so much, I will adjust my schedule when I do multiple/varied layers/thicknesses.  In regards to the anneal cool, I've been able to get away with a lot of bad habits using this small kiln and the projects I've been doing.  But as I progress, I will pay more attention to this.