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

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

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

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

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

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.

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.

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.

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

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

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

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.

thank you very much for the video, a question for the very small pieces, how do you recommend doing?

Complex double boiler? Wouldn't a Au Bain Marie setup work? I'm sure you've got a glass bowl and a sauce pan at home to try it with

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.

Im currently experimenting with melting runners down to make duplicate parts, as of right now iv had two fails. I know one of them failed mostly because the mold i made wasnt quite up to snuff, the second piece looked as if i hadnt used enough melted plastic. Maybe try more plastic and making multiple molds of the same part to make sure your mold isnt damaged from removing the original part you're copying.

This is a cool idea. I hope to see more experiments.

How about sandwich type molds? You know, where you need to apply pressure?

I tried melt the runner using candle in the metal plate that usually use for paint. It formed a nice round plastic. Am still looking for way to cast something more useful

Great video! Awesome you experimented so much! You are a winner!

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

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.

I have a question. Can you make two pieces mold using plaster/gypsum powder? Silicone is kind hard to get in my place.

I had an idea well watching this idk if it would work but let's say you melt it all down and make it into a sheet similar to plaplate?

how about if you use it as a the liquid material for 3d printing? are they both the same type?

What if you go over the finished product with thin cement to melt and smooth out the imperfections?

I would totally love to see how you make molds.

Try placing the mold in an air vacuum if you can find one, it might help reduce bubbles

Seems like it might be necessary to add some more additives to help preserve the structure.

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

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

What ratio of plastic to acetone did you use to get the taffy consistency? I have an idea of using this method to roll out flat sheets to make home made pla-plate.

From videos I’ve seen, when you made the silicone mold for the cast, you didn’t use a vacuum sealer to get rid of the bubbles in the silicone. I think that’s why there’s always gonna be bubbles. Maybe even vacuum seal your resin too but idk bout that

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.

Curious what kind of ventilation you got going on.

what if you pour resin into those molds, would that work?

those imperfect molds can be used for battle damaged parts

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.

Perhaps using a two part m9ld to allow "painting in" a layer of plastic to act as a thin shell before adding in more plasric to bulk out the structure.

1.can i use 20ml tamiya cement (yellow)? 2.how long it takes to "melt"??

Tell me sir glue your using in video?

How do you make polycaps?

i know this is and old video, and i have yet to look to see if there is an updated version, but would a vacuum chamber or pressure pot help get rid of bubbles like with resin?

are you sure its got nothing to do with how long you let it cure and the temperature of your room?

so i melted down some gundam runners with acetone to make a replacement part i can not find anywhere and i was wondering do i have to let it dry for a very longtime to hard good because my first try the part came out very soft and was a nothing like the video lol

I really like two part molds when it comes to trying to do something like this

you can just heat it up slightly also in the microwave helps with making it more runny works wonders

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

What about getting a candle warmer? Just put the parts in a Pyrex dish sitting on a candle warmer and turn it on. Very slow warming with indirect heat. Shouldn't burn or bubble and will give you liquid plastic with no solvent.

Yo, I recommend getting a drill master heat gun. It melts plastic quickly and isn't gonna ruin your lungs

Will it still solidify after being melted by acetone?

Hi, do you think this would still work if you used oyumaru for the mold?

What about thermal melting?? Use that glass syringe but warm it up before any plastic goes near it and suck up hot molten plastic then inject into your mold

I think if you sand it down it will look smooth and scribe the details

not bad dude. thanks for the hack tips for me, i dont care for bubble. it can be fix with some work of sandpaper and filling with putty (or with that melted spure) you can painted after all, in that case for shoulder zaku of course doing some project like this with acetone it require mask to do it, the fume is dangerous for lung

If you still have those warped parts, you can probable still use them as old or damaged gundam parts, or build an entire Gunpal figure from them, but as old or destroyed background pieces too XD

So i think what you need to do is add multiple injection points into the mold and an exhausting holes or gates to vent the trap air when injecting. Use any runner tree to make use for injections and venting paths.

You have to put it in a vaccum to get rid of the air bubbles

hmmmm but you can make some pretty sick stuff though. like weapons, diorama parts

what could i use for the molds???

with what liquid did you melt it

Will a 2 part mold work? Sorry for asking I'm new to this

Should learn making mold using dental flask/bantam flask. That's how dental technician make denture mold for acrylic dentures. I'm not yet on the point of making duplicates of parts. But if it comes to that. That's what I will do.

You looks like you used the thin type have you tried using heavier duty plastic cements?

Sprew goo is a good thing to have on hand lol

2:26 Ayo, where’s that clip from?

Never reuse acetone rendered plastic. The quality of the plastic dimensions every time you do it. you need to use this little acetone as possible in a in a sealed container and let it sit for several days. curing the molds in a super cool environment to prevent pockmarks. If the acetone evaporates too fast it creates bubbles. Try investing in a scientific hot plate with super accurate temperature control. With a pour mold and hot melt plastic your copy's will be much better off and easier to finish.

Looking to the injection molding system you're going the right path but you should always introduce at least 40 to 50% new plastic using the old plastic which has been melted down will never give you true consistency if you can try using it tumbler system or heating system to melt the plastic take a look at how people make their own filament for 3D printers that should answer a lot of your questions

Yes please teach me how tow make li

You can make this with oyumaru beside a silicone mold?

Finally I can fix a broken peg

$500 elegoo saturn. Prints in 4k with submilimeter accuracy. It would be alot faster and easier on you.

This is a well-made and informative video, so I don't want to dislike it, but you totally clickbaited us all with that title. Best of luck though, I hope someone can figure out a more consistent process for this in the future.

Title is clickbaity, the concept if interesting and its fun to see the effort.

I tested double boiler...... and the double boiler can't be used with food anymore

DAMN!!! I was excited to do this but it's a fluc

Doing it in a vacuum would prolly fix your air bubble problem

melt it with heat instead

I'd love to see your method the more we can see the better we can all refine it

I least you tried

While not useful for you. I’m pretty sure I can use this to patch my broken beam saber. So thanks.

uhmmm ... i think the problem not lies on the recycle abs... but yea... the recycle wont be as fluid nor as accurate compare to the 1st

Hi hi hi man go youse a 3d prienter

And may be you have not youse a lot of tameya seman dan dat might got the results for the parts 😅😅😅😅

maybe use resin and put in a vaucum pot. to pull the air our. try that on a silicone mold as well to maybe get a better mold of the part

Man the title is such click bait