klindsay Posted March 3 Report Share Posted March 3 Hi! I am making a plaster mold for the first time and the piece I made is now bone dry. Can I make a mold from this or will the piece dissolve before the plaster is set? Is there a way to avoid this? Thank you! Quote Link to comment Share on other sites More sharing options...
Jeff Longtin Posted March 8 Report Share Posted March 8 Hello Klindsay. Welcome to the Forum. Yes, you can make a mold of a bone dry clay form. It shouldn't dissolve. (As you suspect.) It will/might soften, however. That' where it could get complicated. Years ago I made a mold of a seven piece doll form. (In total the finished form was about 24" tall.) I got to the project later than expected, as in weeks, and the pieces were mostly bone dry. Out of caution I applied Murphy's Oil Soap to all the pieces but I think that was unnecessary. While the pieces didn't dissolve they did break apart when I tried to remove them from the molds. The client was very unhappy and I was very unhappy. She didn't get the molds she wanted and she didn't pay me the full amount. Since the forms you want to mold are now bone dry I would suggest you bisque fire them before you mold them. After the firing you can seal them with a spray acrylic paint and they will survive the molding process and allow you to remake the molds if necessary. Good luck. Making molds is never as simple as most people think. Quote Link to comment Share on other sites More sharing options...
Chilly Posted March 12 Report Share Posted March 12 Agree with @Jeff Longtin. Clay masters should either be wet or bisque. Only issue with bisqueing is the shrinkage, so if that will be a problem, you can add a skim coat of clay after bisque, to make up for lost volume. Quote Link to comment Share on other sites More sharing options...
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