Missing mold piece

[Eve.Fedyk]

Hi all. I'm missing the back of my favorite mold. Is there a way to make a new one to fit the front with a piece of greenware previously cast on it? Thank you for your help.

[Jeff Longtin]

Good Morning Eve,

Welcome to the Forum. Do you have experience making molds? You can make a new mold piece but since your greenware piece has already shrunk a little bit I would make a complete new mold instead.

To be on the safe side I would also fire the greenware piece to bisque temp. Then seal it with acrylic paint. 

To simplify your life I would use the remaining mold piece as a starting point and use it in the molding process. Making sure the bisque is sealed and applying three coats of Murphy's Oil soap, to the plaster mold piece, pour a new mold side. The plaster will probably seep down between the mold and the bisque piece but that's alright. After the plaster has set up, 30-40 minutes, open up the mold and clean the seam. Apply three more coats of Murphy's, to the new plaster mold piece, and pour side 2. 

If you were hoping to just drop the greenware piece into the existing plaster mold and pour a new plaster piece you could do that BUT you run the risk of the plaster not cooperating and going places you didn't expect. Then you may be forced to clean new plaster off an old mold. (Been there, done that...not fun.) 

Good Luck