05/15/2026
Duplicating Astroboy! 2 Part Mold with ComposiMold and ImPRESSive Putty-both reusable, reformable.
Here’s how we duplicate the action hero using re-usable molding materials
Start by heating the ImPRESSive Putty in the microwave for about 3 minutes in short intervals. I used a 1 pound block ImPRESSive Putty. Time will vary depending on microwaves. Be careful when it is first heated. It’s hot. Let it cool before pressing.
Smooth out the putty so no lines are in it. Press the figurine into the Putty. Move, squeeze, and shape the putty to put the parting line where you want it. It does not have to be flat and can form around the shape that you are molding.
Press some dots into the putty. These will make it so the two halves of the mold are aligned when put back together.
Spray with Bubble Buster to reduce bubble formation on the second half of the mold.
Both ImPRESSive Putty and ComposiMold are reusable molding materials, so you can make dozens of unique molds with the same material.
Melt the ComposiMold in the microwave for about 3 minutes. Pour over your figurine. And let cool.
Use a paperclip or toothpick to pull away any bubbles from the side of the Astroboy. You don’t need to break thebubbles, just get them out of any crevice on the actual part. The transparency of Composimold is nice for this.
Let it cool. Pull apart the mold halves. They won’t stick together. The Putty cooled in about an hour in the freezer. The ComposiMold cooled in about an hour as well after I put him back in the freezer.
The putty does not need a mold box, but it helps in this case to create a boundary because I’m using ComposiMold for the second half of the mold.
Is Astroboy the coolest super hero? And what’s better than one Astroboy? I say two Astroboys and customized Astroboys are even better.
Peal the mold away . I carefully pulled the Composimold out of the gun barrel.
We could also have done both halves with ImPRESSive Putty, but the ComposiMold, because it’s pourable fills in all the gaps well to make a more detailed mold. And the ImPRESSive Putty replaces the clay usually suggested for two part molds and simplifies the two part mold making process.
I wanted to pour the resin into the back, so I picked the highest point in the back and drilled a sprue hole there. I could also have gone through the feet or the head.
I used ComposiCast White with ComposiMold Epoxy Pigment Tan. What’s nice about the ComposiCast Resin is it works really well with the reusable molding materials, doesn’t create a lot of heat during curing, and best of all, you don’t have to be that accurate with the mixing because you can be off by 15 to 20% and still have a nice hard casting. So mix 1:1 by volume or weight. It only took about 3 drops of colorant.
I brushed the resin over the front of the mold just to make sure all the small areas were filled. You don’t have to do this, but I figure it can’t hurt. I also did this on the back part of the mold, but I don’t think that does a lot since the resin will just drop down. Put the mold back together and carefully pour the resin into the sprue hole until it’s filled. You can also use a funnel, a paper funnel, or a syringe to help get the resin into the sprue hole. Syringes are great for smaller parts. We could also have placed to sprue holes in the legs and maybe his back so we would know when the mold was full. The resin will start coming out of the sprue holes. The awesome part about reusable molding materials is that you can e xperiment. So if you think of other ways to make this, try it and see what happens. Tap the mold to help any bubbles escape. Let it cure overnight.
Pull the mold apart…be careful around the delicate areas. After this mold you next you can make another Astroboy, or remelt the Reusable Molding Materials to make new shapes and figures.
Tada.
I little bit of the ComposiMold broke off in the gun hole, but other than that it came out great.
Clean up the edges. Most of the extra plastic came right off, but you can also sand it and clean up the edges with a dremel tool. You can paint the figure now to make it any way you want.
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In Japan, Astroboy is Mighty Atom. It was a comic book in the 1950’s and 1960s and created by Creator: Osamu Tezuka
This Astroboy design is based on the 2009 movie.
