Thank you for you excellent information. I was able to make the piece that I needed, and while I was sure it would blow up, it did not. I fired the mold in mh oven very slowly to be certain it was dry before I put it in the kiln, and then ramped up slowly in the kiln and did not have a problem. I will be able to use the mold several times. I am always very cautious when trying a new procedure and had never made anything out of clay – so now I know how to do it.