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Strelnikov

Making a mold

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Strelnikov    2

After you get that Grand piano cut the top into some coddle boards and save a large square for the bottom of mold.This top may have stain rings from some of Jims vitracation experiments that weeped thru.The rings will not bother the mold process-stick to major brands like Stienway or Baldwin as they have a smoother wood finish.

As far as brands of green soap any green soap will do-better still is mold release sold at ceramic suppliers.Green soap will leave a small foam but it will not show once plaster is poured.

Mark

 

 

I'm going to try Murphy's Oil Soap next and pull the boards sooner than I did the first time. The vaseline didn't work so good. There were places where the plaster stuck to the wood even where I put on a liberal coating of vaseline.

 

Evan

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OffCenter    82

Just ignore Jim. Most of us do. But I find him funny, so I don't. I do know how to cast plaster though.Mark Cortnoy has good advice.

TJR.

 

 

I definitely don't ignore Jim. He's got some of the best stories on these forums, not to mentioned, I'm a fan of his work.

 

 

That's awfully nice of you to say that, Benzine. I guess you're not such a bad guy after all.

 

Jim

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BeckyH    42

Remember, you need a collar or reservoir for your slip when pouring the mold. The water in the slip will get sucked into the plaster, and the level of the slip in the mold will go down. You need a big enough space at the top of the mold to hold the extra slip. I like to plug the top of the object I'm casting and pour a slab about 2" deep. When it is just cool I cut a pour gate that just matches the top of the object. You need to cut keys in the main part of the mold- just a few depressions about the size and shape of 1/2 of a quarter- before casting the top, so that the parts fit together properly. Then strap them together to fully dry before making your first casting. It is easy enough to clean up the cast piece with a sponge if the surface is a bit bubbled.

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Strelnikov    2

Remember, you need a collar or reservoir for your slip when pouring the mold. The water in the slip will get sucked into the plaster, and the level of the slip in the mold will go down. You need a big enough space at the top of the mold to hold the extra slip. I like to plug the top of the object I'm casting and pour a slab about 2" deep. When it is just cool I cut a pour gate that just matches the top of the object. You need to cut keys in the main part of the mold- just a few depressions about the size and shape of 1/2 of a quarter- before casting the top, so that the parts fit together properly. Then strap them together to fully dry before making your first casting. It is easy enough to clean up the cast piece with a sponge if the surface is a bit bubbled.

 

 

I'm a bit confused but I think you're talking about a 2-piece mold. I am making a simple 1-piece mold.

 

Evan

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Strelnikov    2

Never made a flat mold I wonder if alcohol water spray might help. Also how Did you mix plaster.?

 

 

I made another mold and used Murphy's Oil Soap instead of vaseline as the release agent. It worked much better than the vaseline.

 

I mixed the plaster with a paint mixer powered by an electric drill.

 

I jiggled and shook the mold and a bunch of air bubbles came to the top but I still had some air bubbles at the bottom of the mold as before.

 

Evan

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Benzine    610

Just ignore Jim. Most of us do. But I find him funny, so I don't. I do know how to cast plaster though.Mark Cortnoy has good advice.

TJR.

 

 

I definitely don't ignore Jim. He's got some of the best stories on these forums, not to mentioned, I'm a fan of his work.

 

 

That's awfully nice of you to say that, Benzine. I guess you're not such a bad guy after all.

 

Jim

 

 

Oh, don't let my comment fool you. I'm a huge ########, just ask my wife, friends, family and students.

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Strelnikov    2

With Murphy's soap I don't use a brush, I use a small piece old t shirt.

 

I started with brush to many bubbles, then wiped bubbles with t shirt rag.... Now I just use small square of t shirt.

 

If any small bubbles I wipe off with moist oils soap rag.

 

 

I found out that if I pour the Murphy's soap on the object to be coated and spread it out with a foam brush it doesn't make bubbles.

 

When I got the bubbles I poured the Murphy's soap into a dish and used a wetted sponge to spread the soap from the dish onto the object to be coated.

 

Evan

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