Moldmaking and casting: Plaster Mother Mold Tutorial

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12 жыл бұрын

This is a basic mothermold support shell for a silicone rubber mold made using white hydrocal reinforced with fiberglass matte. This is a good method for creating thin, lightweight, and durable support shells. When using this method over a brush-on urethane mold make sure a release of wax is applied to the rubber surface. For more information on the skin technique check out our DVD.

Пікірлер: 33

@Dach101 12 жыл бұрын

nice mold making video. Using fiberglass is nice. Like the polishing. Thanks for the post

@cpmills 12 жыл бұрын

I've never thought to use fiberglass instead of burlap. I'm going to have to try that for my next stone mold.

@bitymoldsupply 12 жыл бұрын

@Tomcreature Ultracal 30 has very different working properties and is much heavier than Hydrocal. For this type of support mold we need something strong but we also need something relatively light. Hydrocal allows for a fast cure as well as a gradual thickening that aids in this type of mold process.

@bitymoldsupply 12 жыл бұрын

@KewneRain That's why we add the fiberglass matte!

@bitymoldsupply 12 жыл бұрын

If you are using burlap cut into squares they should overlap each other half way giving you a total thickness of 2 layers of burlap.

@bitymoldsupply 12 жыл бұрын

The downside to using petroleum Jelly for this process is that it does not dry. Paste wax dries. Paste wax is also right about the same cost so it just means walking to a different isle in the grocery store.

@bitymoldsupply 11 жыл бұрын

Hydrostone is a stone so the application and mixing process is different. The main difference, relative to this process, is that Hydrostone is designed for casting and set quick with little warning. Hydrostone does not have the gradual set of Hydrocal.

@lolliequeen101 11 жыл бұрын

Ok I'll go buy some Hydrocal then. Thanks for the reply.

@bitymoldsupply 12 жыл бұрын

@Minifisen Yes.

@inkspray 12 жыл бұрын

About how many reinforcement layers should you have using burlap fabric, cut into strips?

@bitymoldsupply 12 жыл бұрын

70-30 cures in ~16 hours. That's when you can start the mother mold.

@calabiyou 11 жыл бұрын

can anyone explain what flashing is? I understand it to be sculpting a channel against the sculpture so when it's molded there's a way for excess material to leave the mold to allow the mold to close properly. is this correct?

@lolliequeen101 11 жыл бұрын

I think I have some hydrostone, could I use it instead of hydrocal? And whats the difference between these two plasters?

@inkspray 12 жыл бұрын

How long should the silicone mold cure prior to applying the plaster for the mother-mold shell?

@vessybeta 11 жыл бұрын

I didn't see fiberglass mats/mattes(?) on your site. What brand and weight per square foot do you use and where do you buy yours?

@bitymoldsupply 11 жыл бұрын

I used fiberglass matte that I found at a local hardware store.

@inkspray 12 жыл бұрын

ok thank you

@bitymoldsupply 12 жыл бұрын

@omex2005 My condolences...

@JonnieZombie 12 жыл бұрын

Do you think you could spend a video briefly going over the most important tools and their applications?

@bitymoldsupply 12 жыл бұрын

For 71-20 I wait ~4hrs after I apply the final coat.

@bitymoldsupply 12 жыл бұрын

@Lurker1979 That is a 100# bag.

@bitymoldsupply 11 жыл бұрын

Nope. Flashing is the casting material that seeps into the seam of the mold. The better the seal on the mold the less flashing there will be on the cast part.