Quick-and-Dirty Mold-Making and Resin Casting For Newbs, Part 1 (Materials and Equipment)

I’ve been meaning to make this post for a while. It’s the product of more than a year of horsing around and testing, using a somewhat uncommon method of casting. This method is best for short runs (less than ~25) of items without especially dynamic poses or deep recesses/spindly projections. My failure rate on casts is about 10-15%.
First, before we get into this, some notes on legality (and remember, I’m not a lawyer, just an opinionated internet asshole from America) :

• It’s technically legal (in the “not-criminally-actionable, but still-naughty” way) to cast stuff for your own use, and of course anything you’ve sculpted >entirely< yourself or using parts cleared for reproduction is okay.
• It is all kinds of illegal to sell or (to a lesser extent) even give away models based on/including parts from someone else’s work. Get permission, get a contract, and get a lawyer before you start even thinking about doing casting for someone else.
It’s actually much more complicated than that, between FASA vs. Playmates and Chapter House Studios vs. Games Workshop, among others – but this is a decent guideline for not getting your ass sued.

Selling “Garage Kits” (short-run, self-sculpted models of something that the official licensor doesn’t make) is still illegal, but usually tolerated. If you do still want to break the law here, remember that it’s in the same general category as fansubs: don’t mass-produce, don’t do anything to twit the creators, and immediately back down if you’re challenged or even requested to. Not that I’m advocating it, of course.

• It is a DICK MOVE to take recasts into a store that sells that product line. No-one cares how “legal” it is, you’re shitting where you eat. Don’t take them to tournaments either, you will eventually get busted and ejected. Similarly, if you’re making garage kits or even recasting for your own use, don’t post about it on official forae.

Finally, there’s something a lot of people on the Internet forget –

You have no “free speech” rights in a private forum or place of business.
The owners are completely within their rights to kick/ban/C&D you. They can, and will, so fucking fast it’ll make your balls slap your voicebox.

Now then, with that out of the way, let’s get into the materials and equipment you will need.

General Tools:
A craft knife (as if any project didn’t need one..)
A large supply of clear plastic cups and disposable craft sticks/coffee stirrers. Wood is fine. If you can find a Cash and Carry or other professional kitchen supply store, you’ll be able to get these in bulk for cheap.
• You can also use glass beakers and rods if you’re made of money. I’m not. A narrower mixing cup makes making large molds harder, but allows more precise measuring. Try to avoid major taper in your cups
Total cost: ~$15. Most of you will already have these, however.

Safety & Cleanliness (IE not wrecking your other shit):
• Non-silicone rubber gloves. I use disposable nitriles
• Clothes you don’t mind ruining. I actually have a set of “casting clothes” that I keep in my workroom.
• A cardboard dropcloth for the floor – the resin doesn’t soak through it if you spill.
• Waxed paper or several layers of newspaper to shield your casting surface.
• Invest in an organic-vapor rated mask. This is non-negotiable if you’re making more than a few casts, or you WILL become sensitized to resin. Do you want hives inside your lungs? No? Then get a fucking mask. Don’t skimp and get a “dust” mask – that’s fine for sanding and working the resin later, but you need the vapor mask to handle snorting up the resin fumes.  If you’re doing short runs, you can probably get away with using a space with really good ventilation and leaving during the casting process, but I still wouldn’t take the chance.  You’ll need to replace cartridges every few months, so try to do a bunch of casting at the same time to maximize your value.
Cost: Assuming you use Goodwill, the clothes will be about 10 bucks, the gloves are $1.50 a dozen at Home Depot (or Cash and Carry), cardboard is basically free. The mask will run you ~$20.

Mold-making equipment:
• Legos or similarly interlocking building blocks, with a baseplate slightly larger than the materials you’re going to cast. Getting all one color helps. You can find sacks of them in the local Goodwill or Value Village for about $3, or just order a shitload of 2×4 bricks from one of the manufacturers. You will be ruining these Legos for anything but moldmaking.
• An oil-based clay. Unlike me, you should probably get it in a different color than you chose for the legos.. Silicone-based clays will become an unholy mess, and water-based clays interfere with the chemical reactions.
• Tin-cure Silcone rubber. I use “Oomoo” from Smooth-cast, because it’s a 1:1 by volume mix, but the 10:1 by weight mixes are actually better-quality and less bubbly. Acetic-acid cure (most silicone caulks) is chunkier, harder to pour, and will immediately and very severely corrode lead masters, as well as giving off an unholy stink.
• A small sculpting tool. A craft knife will do in a pinch, but you really want something with a flat, blunt head.
• If you have it  – and you will soon enough – scrap rubber left over from other pours and worn-out/miscast molds, diced into ~1/4″ chunks.
• If you’re using 10:1, you will need a gram scale. I picked up one from the kitchen section in Target for $12.
Costs: The rubber will be your biggest individual expense. It’s about $25 for the rubber, which will make around 20-30 mold halves for a 28mm model depending on the cast depth. ~$5 for the sculpting tool. The cost of the legos depends on the source and the size of the molds, but even buying them straight from the manufacturer the ~50 I use for a 28mm figure would cost ~$15. From Bricklink, it’s more like $2. The clay is about $5 for far more than you’ll actually need.

Resin Casting Equipment:
• A fast-setting 2-part resin, preferably a 1:1 mix ratio. I use Smooth-Cast 300 Bright White.
• A small steel pin or paper clip
Costs: ~$20 for the resin. It’s 2 quarts, and considering a 28mm fig needs about a tablespoon of resin.. it’s a lot of minis.

 Shit You Don’t Need, But Is Very Nice. And Expensive.:
• Vacuum table: will pull the gas out of the curing resin and rubber.
• Vibrating table: shakes out the bubbles, but can disturb delicate parts.
Cost: Too damned much for me to test one.

Overall, this setup will run you around $60-100. If that’s more expensive than it would be to just get more of whatever you’re casting (or you don’t need 10-15 different molds..) then you should probably consider just buying the stuff outright.

Next up: Throwing the Mold (Part 2)

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2 Comments

  1. Quick-and-Dirty Mold-Making and Resin Casting For Newbs, Part 2 (The Mold) | Doc Schott's Lab
  2. Quick-and-Dirty Mold-Making and Resin Casting For Newbs, Part 3 (Resin Casting and The Final Product) | Doc Schott's Lab

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