Now you’re ready to fulfill the destiny of your sculpture and reincarnate him many times over. Or maybe a few times over. You might want to determine a ballpark figure for your run size in advance. A good silicone mold should last from 45 to 100 high-quality castings.

Is there interest in your model? Have you shown him around, gotten critiques, taken orders? Produce what the market will bear.

I mentioned this earlier. Rotational casting is a method in which the mold is shut and sealed, and then turned upside down and around to allow the resin to flow evenly onto the surface of the cavity. If you’re doing a small run, you may just want to do this by hand. It’s difficult to keep the resin even, and you will probably end up with thin spots and bubbles that need to be filled with epoxy.

The main advantages of rotocasting are the avoidance of most structural bubbles, and big savings on production costs, since you’re only using about half of the resin that a solid model would take. Hollow models are lighter, and therefore will not cause the legs to bend as quickly over time.

If you’re really totally absolutely maniacally professionally serious about this model horse production stuff, you may want to invest in a rotational casting machine. There are various configurations, the most common of which are a rotating-arm type such as the Machine Designs models, and the frame type such as Mannetron’s machines.

I’ve heard (this could be untrue, I don’t know for sure) that the Mannetrons are better for heavy, nonstop production whereas the arm-type machines can be prone to overheating. The type of rotocaster you need depends on your production goals, and your budget.

The big frame rotates on one axis, and the small frame rotates on the other. The knobs are for speed and directional control.

Another way to avoid bubbles is by pressurizing the mold and resin inside an airtight pot to between 60 and 100 psi (4 and 7 bar). This is particularly good for Stablemates and other small scales. The model will be solid and dense, because the air will actually dissolve into the plastic when it is in liquid form.

A commercial pressure pot is available, and some artists use autoclaves. This is the opposite of vacuuming, and a different pump is required.

I spray both halves of the silicone mold and both halves of the mother mold with release agent prior to casting each time. There is always a chance for resin leakage, and if it gets between your rubber and mother molds it could cause distortion problems. If properly released, the escaped resin should peel off easily.

Keep both molds clean! If you have vents, make sure they’re clear before each casting or you’ll likely end up with a model that is missing vital parts such as legs, ears, or even the nose.

An industry standard is the use of baby powder to prevent surface bubbles. A thin layer of it breaks the surface tension and allows the resin to run evenly and bubble-free. The use of powder also gives your casting a nice matte finish. Buy an unscented brand unless you want to have weird-smelling castings! If you can get generic talcum powder, this is the same stuff. I use big soft brush to fluff powder into the actual negative space of the mold, making sure it doesn’t accumulate too much in the fine details. It’s also a good idea to wash the mold every ten castings or so to get rid of any buildup of powder and release agent that can be a potential problem with seam fitting.

How cute!

“Flashing”occurs when resin leaks out of an improperly sealed seam.

Keep your mold clean!

I have gotten some pretty good dinosaur-horses out of this, however.

Steel reinforcing

Most resin casters reinforce fragile areas such as legs and the tail with steel wire. This is an excellent idea, and I highly recommend it. I haven’t tried it yet in production because Heather is too small to worry about, but you may want to experiment with this.

This is up to you. Do you want to market finished, painted pieces, castings that are directly ready for paint, or “raw”castings?

Sometimes no matter how accurately and consistently you produce castings, you’re going to have a couple of epoxy fills. I use Apoxie Sculpt from AVES studio. The only drawback is the color, which conflicts with the white resin and makes it difficult to tell if the surface is even or not. They do sell a “white” epoxy that has a slightly different texture than the normal “cream.”

If you’re going to market exclusive, one-of-a-kind painted masterpieces and want information on how to paint, this is not the website for you; do a Google search. I am in no way an authority on finish work. Good luck!

This would be an awe-inspiring sight if she were more than two- and-a-half inches tall.

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