Posted:  16. 03. 2023.

 

I've been sculpting miniatures for a few years now, and my figures have been released by Harwood Hobbies, Mammoth Miniatures, Smash Bash, Meridian Miniatures, and others. It's always been specialised professionals doing the moulding and casting for us, and I had very little knowledge about those processes. Sometime last year I made up my mind to start dabbling in this area of the hobby, and become able to make silicone moulds and use them to cast resin figures. First order of business was to get informed. I spent a while reading about resin casting and watching videos, just to see what can be done, what is the usual procedure, and what tools and materials I’d need.

Then I had a happy little shopping spree: bought silicone, resin, sulfur-free plasticine, mould release agent, cups and sticks. I already had gloves and a respirator, which I use when spraying primer. What I did not get were a vacuum chamber and a pressure pot. I first wanted to see how it goes without them before investing in the devices. Small steps.



CASTING WRAITHLINGS 

All the materials arrived, and I could have my first mouldmaking attempt. This was around six months ago. I had already sculpted very small figures of Wraiths and Grobnik artefacts in preparation, which would be my test subjects. I thought it would be neat to later use these moulds to se up any leftover resin from casting other figures. I could then carry a handfuls of those little figures and give them away to people I meet at events. You’ll see the Wraithlings in the images below. The Grobnik artefacts are going to Mammoth Miniatures to be cast properly and released with the next wave of Grobniks.



I did not make a two part mould, but poured silicone over the minis glued to a surface with an overturned bottomless plastic cup surrounding them. When the mould was cured, I cut into it with a hobby knife to release the originals. The castings would be released the same way. Sadly, I don’t have any photos of the process from back then; just the journal entry. This is the silicone mould for four Wraithlings:



I had a little disaster where silicone poured out all over the table. The overturned plastic cup I was pouring silicone into was glued to a flat surface with a good amound of hot glue. It seemed sealed enough... A minute after I had finished pouring, a blue puddle began to form. Luckily I was doing this in my garage, and I had the surface protected. Still, it was an intense few miniutes of panic.



The moulds successfully cured and resin poured in. It was exciting, even though the results were flawed. There were copious amounts of air bubbles in the resin. Larger air pockets that formed in the Wraithlings' mould were especially nasty. Half the minis often came out of the mould headless, since resin did not manage to get in there. I tred to use a syringe to inject resin deep into the mould, and I tried using vibration to expel the bubbles a few times. Neither one of those fixes made any significant difference. You can see some of the defects below.



CASTING WRAITHCHUNGUS

After the initial attempts, I put the project on hold for a while and focused on other things. The second round didn't come until the beginning of this year. I decided to try this with a much bigger figure this time, to see if that would make it any easier to mould and cast well. I sculpted a truly chonky Wraith in Super Sculpey. This time, I wanted to do a two-part mould, so I rescued my childhood Lego bricks from the attic. Unlike last time, I remembered to take pictures. So here’s how it was done:



The figure was sculpted and baked. This one is around 50mm tall.



With the assistance of my skeletal minions, I built a frame for the mould out of Lego bricks. From what I've seen online, this is a widespread method for homemade silicone mould making.



The figure was put in the frame, surrounded by plasticine. This plasticine must be sulfur-free, because sulfur can prevent silicone from curing and ruin the whole show. Bottom half of the figure needs to be submerged into the plasticine layer. The bumps and holes I placed around the figure are registration keys. They will help the two parts of the mould align perfectly for casting. The two toothpicks connecting the frame wall with the Wraith's ruff are vents. Air can escape through them while resin fills the mould, resulting in fewer trapped air bubbles. Before pouring the first half of the silicone mould, everything is sprayed with release agent to prevent sticking.



First half poured. In order to minimise air bubbles in the silicone, I poured from high above, and aimed for a corner away from the figure. This silicone is mixed 1:1 by volume, and once it was mixed I had 45 minutes to get it in there. Plenty of time. I left my team of trained skeletons to supervise it for the next six hours until it was cured.



The mould was removed from the frame and flipped. The plasticine could now be removed, for its place to be taken by more silicone. The whole thing was returned into the brick frame face down and sprayed with release agent. Time for another silicone pour.



Six hours later, the two part mould was ready. I got my resin in there and waited. A few hours later the first casting popped out without an issue. The mould gets filled nicely, but a swarm of tiny air bubbles are still an issue. The figure is fine for personal use, since I can patch up the imperfections with putty. But I don't find it good enough to sell or give away.

I’m definitely getting both a vacuum chamber and a pressure pot. The former is generally used to get rid of iar bubbles in your silicone, and the latter to degas your resin. The result should finally be decent quality castings. If you have any recommendations when choosing a device, leave them in the comments.

I will also be getting a dye for my resin. This bright white is not pretty, and it's hard to see tiny details before it's primed. Any recommendations for resins are also welcome.

I'd love to hear about your own experiences in resin casting, both good and bad.



I had some fun customizing the oversized Wraiths. I had a go at another new thing: gold leaf application. It's a simple process, but the material’s a bit difficult to work with. The sheets are so thin and delicate, and get crumpled and torn very easily. First you apply special glue, and after a while you can stick pieces of gold leaf to it. I painted my figure black first, since I didn't want any whire resin to peek through the scratches on the gold layer. I also used a brown oil paint to grime it up a bit in the end. I like the effect overall. Would be cool to gild up statues when making scenery.



As always, thanks to all of Gardens of Hecate’s patrons! Your support is sincerely appreciated. If you’re not a member, you can join here anytime: PATREON. The extra coin allows me to experiment with new ideas, tools, materials and techniques - such as silicones, resins, and vaccum chambers; and produce quality content for everyone to enjoy.


 
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Comments
 

DIY can be pretty cool, but I think I’ll leave casting to the pros. smile

Hey, what can you tell us about your work on The Doomed?

https://ospreypublishing.com/us/doomed-9781472854261/

By Marc on 2023 03 18

I was commissioned by Osprey Games to kitbash, paint and photograph warbands and monsters for The Doomed rulebook. There’s not a lot of info about the game out there just yet, but you can check out this article:

https://www.wargamer.com/warhammer-40k/monster-hunter-the-doomed

By Ana Polanšćak    on 2023 03 20

Oh the molds. I tried to copy some tanks long ago with some success. I did one part molds because the pieces has one flat side. Unfortunately the resin get cured inside their bottles and I never tried again.

By Igor on 2023 03 23

Yeah, resin does have limited shelf life. Espeically if already opened. :(

By Ana Polanšćak    on 2023 03 27

I’ve had good results with this pressure pot with my turning blanks and bolt knots. California Air Tools 365CR 5-Gallon Pressure Pot for Casting

By Brian on 2023 05 04

Thanks for the recommendation Brian!

By Ana Polanšćak    on 2023 05 04

oh. my. word. he is sooo chunky i love him

By c. greenhorne on 2023 08 24

 
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