Anyone familiar with using clay as master for resin casting?

[FJ and G]

I purchased 5 lb of Van Aken modeling clay. It's the type that never hardens. I want to make some figures for a new O gauge 7/8" scale railroad I'm building (represents 18 inch industrial gauge in 1:1). Therefore, the figures are nearly 1:12, meaning a 6 ft tall person is 6 inches high, or very close. The actual scale is 1:13.7.

Anyway, the only reason I mention that is that it will be a bit easier I think working on these larger figures than 1:48.

So the plan:

Sculpt a figure.

Paint about 10 layers of Mold Builder (castin craft) on the figure (I may need to figure out how to do each side of the person at a time; maybe 2 molds put together, then trim flashing later).

Add casting resin to the mold and tap bubbles out using vibrations from electric toothbrush.

Later, I'll paint these. I'm making a bunch of the same figures to trade for other stuff, as nearly all 7/8" scale is handbuilt

Also, I might try casting some frogs (switch frogs, not the croakers)

Never done any of this before so any tips appreciated.

NOTE: in a couple months, I'm working on a 3-rail layout at my new office locality. My client supervisor approved the project.

[chuck]

You can try it on something simple.  Make sure the clay doesn't interact with the Mold Builder material.  The chemicals may not be compatible.  What about the heat activated clays (like Fimo?)

[Brutus]

Are you using that Alumilite stuff you posted a link for before?  I think their website has some pictures and also a video you can purchase?

You might try finding some scale figure that's approximately what you want, maybe an action figure at the store or something, then modifying it by building up clothes etc out of clay.  If you are using silicone for the mold, I don't think this would be a problem.

[trigtrax]

I have used clay with epoxy to make single use molds.In general I use this method to repair broken caboose roofs or boxcar ends. You can cast alumilite in a clay mold.

If you looking to produce many exact replicas you should try a jewelry supply company.. There are liquid vinyls and rubbers that cure with moderate heat (275 degrees F.) and form durable molds. For stuff like that I use a vacuum chamber to remove trapped air.

[jefelectric]

Dave,

You might want to check out the dollhouse suppliers.  The most popular scale is 1:12.  They have some very nice stuff, not always cheap.  I am working on my second one for granddaughters, that's how I learned about this stuff.  Here are two sites to check out.

http://www.miniatures.com/hbs/global/index2.asp

http://www.dejouxminiatures.com/

I have purchased from both and they are A-OK.  The last one also stocks more sizes of stripwood than any hobby shop I have seen & they charge only $2.95 shipping no matter the size of your order.

End of commercial!

[jkerklo]

You might want to check out polyomer clay.  It can be fired in an oven.  You can find it in places like Michael's.

It can be used to make things like figures, but also to make molds for more figures.  My daughter-in-law has been using it to make figures, flowers, and small decorations for scenery she develops for my layout. 

John Kerklo
www.Three-Rail.com

[FJ and G]

Thanks guys. I'll post results as they come, good or bad.

John, I really will try to make it up your way soon to visit some of the 3-rail guys.