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"Advise needed about casting some 1/72 - 28mm miniatures" Topic

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1,565 hits since 22 Jan 2013
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Johannes Hus Inactive Member22 Jan 2013 8:03 a.m. PST


I am considering to go into sculpting and casting some miniatures for a personal project.
The masters will be made in Staedtler FIMO soft modelling clay. Beside that I intend to copy some (fairly) hard plastic and metal casts a friend of my has sculpted years ago. For the record, I have his approval copying these miniatures.

I am totally new to molding and casting and I have been searching over the internet to get an idea of wich material I should use. I reckon products from Smooth-On to be a good contender, but I still have a couple of questions about whether it will be sufficient for all my needs.

My needs are:
- being able to copy 1/72 – 28mm sculpts from the 3 mentioned materials; FIMO soft clay, (fairly) hard plastic and metal (tin I suppose).
- being able to copy sculpts with slender parts (like spears for example) without a fair change of breaking or bending such parts.
- being able to copy multiple times. The mold should be fairly durable, as I will be needing some amounts of casts for my project, probably spread over some years, so the rubber shouldn't be tearing or crumbling after some years of service.
- I have no acces to any vacuum-chambers or other fancy tools. What I read about Smooth-On products they give me a more than reasonable result without such tools. This is a requirement.

Finally, I need your kind advise about which material I should cast in. I hear people saying resin would be the thing, others say resin isn't considered to be the solution, but can't name any good alternatives… and I'm starting to get a bit confused about casting materials in general :P

Really hope somebody could help me a little with these things. Somebody having experience with Smooth-On for example?

Maddaz111 Supporting Member of TMP22 Jan 2013 8:30 a.m. PST

How many figures are we talking about, and you may have to use different products to make your moulds depending on master material, I would cast in metal as you can vary it to suit the mould for your own use.

GarrisonMiniatures22 Jan 2013 9:10 a.m. PST

I always finish up directing people to the Tiranti website. Going through the various products gives you a good idea of their uses, for instance. It makes a good starting point for any moulding queries.

Johannes Hus Inactive Member22 Jan 2013 1:55 p.m. PST

Allright, I will go into that site, thx.

We are talking about a big diorama of at least several hundreds of casts…

I reckon casting in metal can't be done with silicones from Smooth-On. As with metals you'll have to heat and melt stuff prior to insert it into a mold.

I was looking at this tutorial:
YouTube link
(covers several movies) and was wondering whether I could use that method…

Maddaz111 Supporting Member of TMP22 Jan 2013 4:18 p.m. PST

I can recommend tiranti, or going to a professional if you have a couple of spincast moulds worth?

are you UK based?

Johannes Hus Inactive Member08 Feb 2013 10:10 a.m. PST

No, Netherlands.

I have been searching around for a while now, and it seems Smooth-On products aren't as durable as I need. But it is very hard to obtain that kind of information on other products…

And sorry for my relative long absence…

GriffinTamer Inactive Member01 Mar 2013 3:24 p.m. PST

I have done a little casting with Smooth-On resins and silicone moulds, making copies of 28mm sculpts I made with Super Sculpey. I am hardly an expert but here are my thoughts based on that experience:

1. You can get some very nicely detailed results.

2. The resin (Smooth-Cast 220, I believe is the one I've used) seems nice and durable, can be carved and sanded, and seems to take paint well. I haven't tried glueing it.

3. Depending on the shape of the sculpt, you may have issues with some air bubbles marring bits of the casts. They tend to appear on undercuts (chins, elbows, etc.). This definitely varies depending on the sculpt; pieces designed with fewer undercuts are much less prone to it. Making your mould right will also make a big difference, as it's important to provide enough air channels (not sure what the technical term is-- small channels running from undercuts back to the top of the mould, to allow resin to flow and air to escape). I have just purchased a pressure chamber to help address this problem, but as it hasn't arrived yet it will be a while yet before I can say anything about how that works.

4. You should be able to make moulds of durable sculpts without damaging them, but if they are made of something brittle (like Sculpey, or probably FIMO) they are likely to get broken as part of the de-moulding process. This needn't be a big deal if you can get what copies you need from the mould, but if the original is important to you that may be a problem. On the other hand, a polymer clay original is probably going to get destroyed by most other mould making processes too.

5. There's likely to be a lot of flash on your casts so they'll need some cleaning up… about like what you get on a sprue of Red Box miniatures.

6. You can get a whole lot of small scale minis out of a bottle of resin. I'd guess 100's from the intro kit size bottle, so long as you're casting multiples at once and you mix carefully and don't waste much.

7. No idea how long the moulds will last. So far I've done no more than four copies of any mini; but after four the moulds seem good as new.

Hope that's helpful, and good luck!

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