Recycle Your Runners! | How I Cast Gunpla Parts from Melted Plastic in Silicone Molds

Watch me try to cast a Gunpla part in a silicone mold from melted runners (acetone and plastic cement). I tried to recycle Gundam sprues after seeing some success making a copy of a HGUC Z'Gok head cap, so now I am making a copy of the shoulder armor for my Erik Blanke custom Zaku II.

Spoiler alert: I failed. :(

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[SoulConvoy]

You have to add a cream of tartar to the acetone/p.cement runner mixture. This is the secret for anybody actually looking

[warhawkbm]

Ummm all I saw were perfect replicas of battledamaged Zaku shoulders. Toss those puppies in a deserted ruin city diorama and you got yourself a battlefield

[joshoppa]

I read somewhere that to avoid getting bubbles you keep your molds on something that shakes slightly or vibrates while it's curing this helps the mold to settle better and helps the air bubbles to move to the top I guess

[DaveDFX]

I did a lot of testing with solvents dissolving plastics for various uses. Acetone is too "hot" of a solvent and evaporates very fast. This causes internal micro bubbles and make parts brittle and discolors the plastic. Use a "slower" solvent eg. Lacquer thinner. You used hobby cement which is a slower solvent. Your putty is too thick and you will not get it into all the crevices. 2 parts mold is better and you can apply thin layers and build up the part. Kind of like slush casting. Pour a watery solution into the mold and get it into all the crevasses. let it dry. This get the surface details. After tat you can putty the rest or build up in layers. It doesn't matter how because it won't affect the surface details.

People get better results using Oyumaru ( Blue Stuff) because it is a stiffer rubber than silicone. Much better with pushing putty into the mold to get the shape. Silicone is too soft and deforms. Silicone is best suited for pouring.

Note: Dissolved plastic in solvents will shrink over time. Not ideal for thick parts.
Personally I would go with resin or epoxy putty that cures chemically instead of evaporation unless you need to fix a straight build with the same plastic and color.

[xtrevoreonx]

I genuinely found this video inspirational. I’m glad you’ve kept at it.

[MrJquintel]

At this point, probably easier (Although more expensive) to just 3D print the part.

[dhamongrimwulfe]

Lol, dang. Wishful thinking with the title. At least you did the trial and error for us. 😁

[FunyunRob]

Have you thought about using a heat gun? I know that using a heat gun can eliminate some if not all the air bubbles in other things.

[loosegoose]

I've seen this done successfully multiple times in a gunpla facebook group im in, however the guy that does it refuses to share his methods, he just says he melted the runner and made copies and that's as far as I know. I suspect he uses either clay or oyomaru blue stuff to make his molds though

[j]

I think your failed casts look GREAT as battle damaged pieces 👍👍

[Gunsnipe]

have you tried to cast an entire model kit out of silicone while the parts were still on the runners?

[ianmuessig]

I just bought my first gunpla kit after a 25 year hiatus. I haven't even put it together yet and I'm already watching videos about molding my own pieces. Talk about cart before horse. Man... My wife is going to hate me when suddenly our house is overrun with little plastic robots.

[dylanclaeys]

Please figure this out. Please. Great video. Thank you for your trials and tribulations.

[skylordianandy]

Finished in a timely manner (he wont)
Boy I feel that.

[eric]

I recommend a two sided mold, because you are not having to force the melted plastic inside the silicone rather using a more melted and liquid base resin.

[ZettatheCrimson]

Bluestuff and epoxy putty would probably be the easies diy at home way to do this if you are wanting a "perfect" part. or bakers clay works too but that would probably cause weight issues on some parts.

[guncross]

Your techniques are good, it's your mould that wasn't perfect ;)

[RivanEXT]

Well good thing I had experience in casting and sculpting in resin. The results of those methods may not be good but I think I could make something usable out of them. Probably gonna try it on the beam effect runners first since I really want to make giant beam sword effects for later customs.

[swatkatfan]

Thanks for this video. I thought I was one of the few thinking of this idea. Definitely gonna try my hand at it as well.

[ScrapCrafty]

I see a few people suggesting a 2 piece mold and from years of working in plastic mold manufacturing plants I would suggest the same while also using a stronger mold like hot glue or even an epoxy based mold along with the injection method you have going. yuo can use a glass or metal drinking straw for the runner port. The only question I have to it would be if the chemicals would have a negative effect.