I have also discovered the need to seal plaster molds before pouring plastic. All have pluses and minus after sealing and pouring. Slipcasting is a ceramic manufacturing process in which liquid clay (A.K.A. I have finally made a few decent plaster molds for hand-pouring soft plastic. Plaster of Paris molds must set for about a day only to cure. After that you can use either acrylic or spray paint. I have tried mod-podge with OK results, but id like to get away from brush-strokes. For house walls you can use PVA but based primer or those sold by Kilz or Zinnser with excellent results. I coated the original part with vaseline as a mold release. For silver or bronze metallic color spray paint would be easier. plaster powder (available on Amazon – also know as Plaster of Paris) powdered tempera paint – THIS IS THE SECRET INGREDIENT (lots of options on Amazon , I used this brand but any will work) silicone shot glass molds ( this is exactly what I used, but there are loads more on Amazon ) Make sure that each coat dries really well before applying the next. Plaster of paris is very porous. If you are painting a plaster mold of a person's face, for example, your base coat will likely be a skin color. May 25, 2013 - Plaster of Paris is an extremely porous material when dried, and as such, will absorb any new water that touches its surface. Assemble your supplies and lay your plaster mold onto a tarp or piece of plastic or canvas sheeting to protect your work space. I have made a couple of plaster of paris molds. The materials listed here can be easily interchanged with others of similar properties. Water Thinned out Elmers Glue, Ace Epoxy, Flexcoat Epoxy, and Devcon. I made a plaster mold for a small fiberglass part I needed to copy. Sealing Plaster Of Paris Molds. A good sealer is watered down pva glue, 3 to 1. Then use an acrylic sealer over the top. Removed the part when the plaster had hardened (a few hours). In order to waterproof plaster of Paris for outdoor use or for temporary exposure to water, you must fill in as many surface pores as possible. Get creative! You may want to seal it first. Hi guys. No jokes about the imfamous Plaster Caster Next … Used household Plaster of Paris. If you take the pieces everyone said, you have an accurate picture. Plaster Mold for Slipcasting a Bowl: This Instructable shows how to make a two-part plaster mold of a ceramic bowl (or just about anything, for that matter) that can be used for slipcasting. Once cured you must paint the bait area with Apoxy, let that cure for one day and your ready to pour your plastic in them. 'slip') is poured i… - Lure Building - SurfTalk. 13/04/2010 I've been playing with several liquids to seal Plaster Of Paris. [ul][*] they make accurate molds[*] they are good for a small number of parts[*] you should probably seal them. Begin by applying a base coat of paint onto your mold.