A couple of more models came out of the kiln this morning, the own center and the Nortown Theater Art Deco panel Nr D7.
D7 weighs 38# and it was somewhat of a surprise that the panel weighs pretty much what it weighed before going into the kiln, I had thought the process would continue to burn out materials, the chemically combined water, and that a percentage of the weight would be lost as a result, that seems not to be the case though it may have lost a very small amount of weight the scale wasn’t accurate enough to register, on the order of less than a pound.
That was good to find out as I now know the final weight for the fired ware will be very close to what the sculptures weighed when bone dry before being fired.
Shrinkage however is another story, as expected, the firing process results in about a 1/2″ shrinkage per lineal foot, so the D7 panel is around an inch shorter in length than it was.
Of course this is a known factor and compensated for in overscaling models if a certain size is required in order to fit it something else.
One could in fact achieve a size reduction in this way by repeating the process, I could take this fired model now, make a plaster mold from it, press clay into the plaster mold and fire that cast and make a silicone mold. The resulting cast-stone casts from that would be consierably reduced in size, but the amount of work involved would be more than simply making a new smaller model.