Wednesday, February 23, 2011
Plaster Mold Repair
I recently read a post on a forum where a doll maker expressed concern over losing a master doll part due to it getting locked in a plaster mold half. Plaster is a rigid mold material, so if the molder does not make the mold half to the correct parting line, the master doll part can get locked in the plaster mold half. However, like I always say, if you can make it, you can usually fix it. In the case of a master doll part getting locked in a mold half, one solution is to cut the mold half with a saw until it is about 1/4 inch (6mm) from the master. Then use wooden wedges and a hammer to split the mold half. The master doll part can then be easily freed from the mold half that it was locked into.
Plaster mold making is a craft skill. The more plaster molds you make, the better you get at making plaster molds. Become familiar with the properties of plaster. Establish good working habits, and follow them. Remember to carve registration keys. Apply a parting agent. Always add plaster to water. A 2:3 ratio of water to plaster is a very good consistency for slip casting molds. Make sure the spare is large enough to allow you to empty the mold when the slip has thickened in the mold. Never put any plaster (dry, wet, or set) in the drain pipes.
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