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DarthVader1

Well, I am still working on a secret project for Dragon*Con this year, but involves a lot of casting in PLASTER, at least to make the first mold of every piece I am planning to do (it involves at least 4 pieces), and they're HIGH-DETAILED pieces to be done vacuuformed....think about a C-3PO helmet, but it's not Star Wars related though, and using .060 HIS.

I will be creating the sculpture with clay, then make a mold out of PLASTER (Plaster of Paris is the choice so far), to then planning to make the castings made of DURHAM'S WATER PUTTY. Some say, including the website itself, that you could work with whatever result as if we're working with WOOD, once it dries up.

My question....have anyone worked with Durham's Water Putty before, and what will be the best release agent out there if I use it with plaster? Liquid? Spray?
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Robert
BH/TK/TB/TS 060

PARATECH1 · Expert Joined: 19 Mar 2008 Posts: 112 Location: ALABAMA

I used to cast Dungeon and Dragon type metal minerature's years ago out of Durham's Water Putty. Car wax or vasolene could work as both a sealer and a release agent. If you put on use one of those cheap black sponge brushes. You don't want to take a chance on leaving paint brush marks. Hope this helps.

PARATECH1 · Expert Joined: 19 Mar 2008 Posts: 112 Location: ALABAMA

I meant to add in the above posts that the car wax would be better than vasolene. It is not nearly as greasy or nasty to work with. If you buff your mold with the wax pretty good, it shoud last for several castings.

Hope this helps.

DarthVader1 · Posted: Tue Mar 25, 2008 2:53 pm Post subject:

Car Wax, huh?! Hmmm, never thought about that one. I will give it a try with a "small something" as a test when it's time to cast. Thanks for the info.
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Robert
BH/TK/TB/TS 060

fast_monte · Novice Joined: 17 Aug 2005 Posts: 40

I bought some of this Durham's Water Putty. I will have to see how it turns out on my next project.

ANH trooper · Master Joined: 20 Oct 2005 Posts: 305 Location: UK

PVA and wax works well for plaster. Depending on the actual shapes you are casting, the moulds might lock onto the casts. One way to over come this problem is to make breakaway moulds. Make the mould of your sculpt in thin plaster, and the casting in thicker, stronger plaster so you can smash the thin mould off and the thick casting is relatively untouched. When I say smash, I don't mean literally bash it with a hammer, but you don't mind if the thing breaks when removing it as your casting is what is important (unless you want to make multiple castings?)

badger · Novice Joined: 03 Sep 2006 Posts: 63

Durhams is great stuff, but it does dry out if the areas are thin enough. I had a mold flake off lots after it dried out completely. Lucky I had already pulled what I needed from that mold.

It mixes like a dream, molds very easily, and once it hits the consistency of ice cream you can use a wet finger to smooth and shape it. Wonderful stuff.

I think it works very well for making molds (I build up a basic form in wood chunks, then fill in with Bondo/Water Putty.) I think it would be perfect for molding over Bondo because it does not smell like crap like bondo does. It just needs to be sealed with sanding sealer once you've got it molded and mostly dried. any thin sections need to be sealed, and once you've got it finished a good coat of sealant is probably wise.

I love the stuff, very easy to work with, molds great, and again smells SO much better.

You can see how I used it on making a Gaffi stick for my tusken costume.
http://box23.net/index.php/badgercostumes/tusken-raider/tusken-tutorial/tusken-tutorial-gaffi-stick

It's held up just fine, no sealing, in all but the very thinnest of parts.

badger

tubachris85x · Posted: Sun Mar 30, 2008 10:49 am Post subject:

Ive used durhams before Ive used bondo. How I feel about it is that its good for filling large or deep areas, but not good if you need just thin spots filled. Thin layers have always just flaked off and all the time I spent trying to use it went to waste. Ive switched to bondo which I think is alot better then durhams. But thats just me
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DarthVader1 · Posted: Mon Mar 31, 2008 4:52 pm Post subject:

I was considering using the DWP to make a casting of a mask from a plaster mold (think a C-3PO mask casting). The cast will be used for vacuuforming, against the idea of doing a plaster casting out of a PLASTER MOLD, since I don't remember if plaster against plaster could stick to each other easily without a good release agent.

I used to do ceramics years ago, and I sort of forgot some of the properties of clay (ceramic in raw form), plaster, and mold release agent back in the days. I am trying to do this project as inexpensive as possible, and avoid the overuse or waste of money and resources as much as possible, at the same time looking for a good substitute of a cast for vacuuforming, instead of going the "SCULPED WOOD" way. Confused

The other choice I have then, is to use SILICONE RUBBER to do the molds, with a plaster bandages support shell, and then do the casting with whatever material is out there.
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Robert
BH/TK/TB/TS 060

badger · Novice Joined: 03 Sep 2006 Posts: 63

I've heard that plaster mixed with some amount of DWP will make the Plaster mold stronger.

Never tried it though.

badger

DarthVader1 · Posted: Sat Apr 05, 2008 2:29 pm Post subject:

fast_monte · Novice Joined: 17 Aug 2005 Posts: 40

I like this DWP stuff! It smells a bit like pancake batter when you mix it up. It appears to dry a bit faster than plaster. I have yet to put it in the microwave to see if I can draw the moisture out of the center faster, I do this with plaster but it is still to slow. It gums up the sanding belt if it is too wet. I wonder how it will do on the bandsaw?

jegner · Posted: Wed Apr 16, 2008 3:05 pm Post subject:

I think Paul has a neat product, a hot cast reusable plastic that he carves up, uses as a mold, then takes the scraps, remelts, and reuses. Don't know what it's called, and I don't think it's available by the same brand name in the US, but cool stuff none the less.

Jim

badger · Novice Joined: 03 Sep 2006 Posts: 63

That sounds intriguing.

and expensive. Smile

badger

DarthVader1 · Posted: Thu May 01, 2008 6:06 pm Post subject:

Sounds really cool.....just think about RECYCLING...literally. Smile

Well, I changed my plans a bit, which also adds a bit in price for the project, but less $$ in the long run. I've decided to just make a silicone rubber mold, reinforced with plaster bandages to make it done and ready for casting.

I was thinking (at the beginning of the thread) about using DWP as the material for casting IF I was doing a plaster mold, but that will be a mess, besides that there's a BIG chance that the casting would've been stuck with the plaster-only mold (I was thinking about ceramics process, though), so I have the rubber, the plaster bandages, and I am going to do the cast with plaster instead of the DWP.....it's cheaper though, but DWP according to the site and comments, it gets hard as rock or wood, which was ideal for casting.
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Robert
BH/TK/TB/TS 060