Why do projects "tear" in the slumping phase?

I have been fusing glass for 15 years and run five to six kins a day year round. So one would lthink I have a fair understanding and grasp of what is going on here. However, without changing our firing schedule all the suddent we will have a rash of projects "tearing" during the slump firing.  Is it the mold coating wearing off? It is never all the projectsin the kilns just of course the most important ones.

 

Thanks for any help.

Puzzled

The time when it starts to

The time when it starts to intertwine is impacted by the rate at which the temperature is climbing when it achieves the melding range. Most combining glass will start to meld between 1400 F and 1480 F. Keep in mind that heatwork is an element of time and temperature. Beginning with glass that has been resolved to be perfect is just the start to a fruitful melding or drooping task. The temperature and different temperature rates in a terminating program must be intended to the particular needs of the task you are making.  As a safety measure you might need to give a dam or hindrance around the glass while intertwining in excess of 2 layers. With in excess of 2 layers, the glass will spread until the point when it finds a level of 1/4" and could stream into another piece or off the rack. for more : website

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