Grrrrr..... stop cracking!

I've done a few fires of the same pieces, repeatedly, over the last few days. Up until now, I've been trying to keep my experimenting relatively simple with small pieces (pendants and coasters) made up entirely of Bullseye (COE 90) or Spectrum (COE 96 - though not all "tested compatible") glass.

But I had two nephews and a niece in town last week and the two older kids wanted to make something out of glass. One of these includes a turtle piece that's a bit bigger and more complex design than I've fused before which means (1) more potential for problems and (2) the less patience I have to pull the final result out of the kiln and play with it (significantly increasing the odds of problems).

But first, a recap. The firing schedule I've been using over and over is the same one that Warm Glass recommends for a basic 2 layer coaster project. I know that the best firing schedule depends on a ton of different factors but I haven't learned what those factors are yet so I've stuck with what has worked.

Starting Temp	Ending Temp	Rate Per Hour	Minutes to Hold
Room temp	1100	300	0
1100	1240	150	30
1240	1480	max	10
1480	900	150	45

Fire #1

	Here's the turtle that my nephew Michael helped to design and make. Bottom layer - clear COE 96 glass Top layer - small pieces of Spectrum glass that are, hopefully, all COE 96. I was too worn out to make the glass fit together perfectly and was interested in how the spaces would look in the final piece. (I like to justify my laziness as an aesthetic choice.)
	I also cut apart the two fused pendants and put them back in the kiln.
	And there was room left for one of the coasters.  I did nothing to change the shape of the pieces. I wanted to see what would happen/if it was necessary.
	Here's the turtle, after kiln firing. Because the small pieces were on top, when they became liquid, they oozed out enough to fill in most of the spaces. Unfortunately, I was so excited about the product that I took it out of the kiln before it was back to room temperature and, worse, washed off the piece to look at it more closely. A nice big cracked quickly made it's way across the turtle's head.
	One of the pendants looks like without my reshaping the glass but the coaster has an extra bump now because of the extra glass in that corner.
	The other pendant is also not circular any longer, because of the extra bit from being accidentally fused to its neighbor.

Fire #2

	I used the grinder to take the edges off of the pendant and coaster from the last round. I also added a glass bail with a little fiber paper to keep it open. My first time using these but I'm optimistic.
	And I added the turtle back in. I wasn't sure that just sticking the pieces of glass next to each other would work to make everything fuse back together so I added a strip of clear glass on top of the break, to increase the odds of it fusing well together.

Unfortunately, at the end of fire #2, the turtle managed to crack even more quickly than the last time. I left it in the kiln alone until it was at 117 degrees (I've never been known for my patience) and then set it down and left it alone for an hour. By the time I came back, there were multiple small breaks. I suspect that I'm going to have to venture outside of my one size fits all firing schedule, to slow down the heating up and/or cooling down of the kiln. At minimum, I'm going to do a bit more research before firing #3!

At least the glass bail attached really nicely:

Lessons learned:

• Small glass on the top layer spreads a bit and can fill in empty spaces
• it sucks to find a turtle that is so pretty but refuses to remain it one piece
• It's time to learn more about different firing schedules.
• The glass bails work really well!