"materials for casting in resin" Topic

I'm contemplating a line of terrain pieces, and have a few questions for anyone on these boards who may have sculpted and built something to be cast and mass produced in resin.

1) Are there any materials to be avoided? I'm currently working with a combination of plasticard, green stuff, and wood.

2) What companies are out there that can make molds and cast my models in resin for the retail/online market? My greatest concerns are, of course, cost, quality, and reliability. Location isn't really an issue.

3) Are there any basic dos-and-don'ts I should be aware of before spending hours on a model?

4) Is it worth it to try to learn casting myself, or should I leave it to the pros?

That's about it for now. More later, I'm sure.

Thanks!

#1 personally I've only used plasticard, metal and miliput/greenstuff. Though i am contemplating using some organic materail like cloth soon. Let us know how you get on with the wood.
#3 The main problems are
undercuts – where the mould goes in toward the bottom of the model – which can be fixed by using the correct grade of RTV rubber – some are more flexible than others.
voids – the rubber mould can't join up inside the model – ie like you can't cast a donut.
bubbles – try to avoid areas that will trap bubbles which are created when the resin is poured into the mould.

#4 Definitely, worth learning yourself, it's not massively difficult and very rewarding. I am assuming as you are doing scenic pieces you will be doing one piece drop moulds – which are alot easier.

General: There is lots of information online, google "resin cast models" or "making moulds" or similar.

Tiranti, IIRC, have a few guides on their website.

I'll leave the other questions for others to answer. PM me if you have any specific questions.

Apparently, you can use wood, but it just needs to be well sealed before attempting to make a mold of it.

Various sources have recommended sealing with lacquer/varnish, and/or Murphy's Oil Soap. Several coats of the lacquer/varnish are recommended, since the wood soaks it up. I imagine several coats of normal spray gloss coat would work as well – one person said they used four coats of spray gloss.

I haven't used any of the above methods yet, so can't vouch for their efficiency.

You can make doughnuts, and/or other hollow shapes – you just need to fill the hole with a thin barrier of plastic, or other material, so you end up with two halves. That way, your casting is not locked into the middle of the mold.

That step is needed for most troop figures, since there is a gaping hole between their legs and base.

1) Are there any materials to be avoided? I'm currently working with a combination of plasticard, green stuff, and wood.

Avoid using anything that is porous. The molding rubber will run into ANY opening. If you do use wood or something you worry might be too porous, put a light coat of primer down on the piece before making your mold. Otherwise, the only thing to really worry about is silicon based clays that might react badly with your molding material. I have seen (and used) fimo clay, green stuff, molding epoxy, plastic sheet, wood, all sorts of odd material in the past and it works fine. Beware careful demolding, often mixed mediums on your master come apart when you demold them, make sure the mold is intact and make yourself a resin "master" of the piece first thing.

2) What companies are out there that can make molds and cast my models in resin for the retail/online market? My greatest concerns are, of course, cost, quality, and reliability. Location isn't really an issue.

We do a lot of contract work for different people and our own products. If you would like to discuss have some of your things done or just some advice or assistance, just drop me a line and I will see what I can do. (www.mondayknight.com)

3) Are there any basic dos-and-don'ts I should be aware of before spending hours on a model?

As said above, watch out for over undercut or anything that is a hole in your piece. If you want to do a window, place a piece of wax paper over the opening. It will leave a thin piece of resin in the window when you cast your pieces, but it can easily be removed, leaving your window open.

4) Is it worth it to try to learn casting myself, or should I leave it to the pros?

Actually, it depends. I started doing my own pieces and it took right off. But I also work for people who tried it themselves, got frustrated, and came to me for help.

Like I said, I will help if I can.

Best of luck to you,
Will

Thanks, guys. I'm going to press ahead with my current model (wood, plasticard, green stuff). If things don't turn out well during the molding process, I'll redo the parts that are now wood. Hopefully things proceed smoothly enough that I can get a decent resin master the first time around.