Resin Casting using a 2 Part Mould with Oyumaru & Siligum

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Oyumaru is amazzzzing. I suggest anyone use it if you are starting out. Sadly this was not done right.

With oyumaru there is a trick to it to get detail. First and foremost use a mold box and apply pressure when putting on the second half of the mold if its anything more detailed than a space marines bum. THEN after you've made the second half of your mold take the first half off, melt it down, and recast it, again in the mold box and under pressure/clamps (you can apply better pressure now with the second half of the mold to push against) then repeat this alternating one side at a time between the two parts of the mold. This will give you bit by bit a progressively snugger fit and better detail the more times you do this (make sure you're reboiling your water each time you melt it down). some other minor details 1. fresh boiling water is a must, and I've heard of others using heat guns to make sure its just as soft as humanly possible but I use the boiling water cause its benign enough to use in an apartment 2. some folks chill one half of the mold before making the second half so the heat of the second half has no chance of deforming the first. This might also let it hold up to some liquid resins (the slower the cure time the better, fast resins get hot) 3. the pressure/moldbox bit also applies to using epoxy clays and putties like milliput or greenstuff they need to be cured under pressure, and if the mold has no vent to squeeze out the excess like playdouh then you need to be using a scale to make sure you're not overfilling the mold.

Oyumaru works great. You've maybe got too big a piece of it. You really need to use it quickly while it's hot. In small amounts. Upside is it hardens instantly in cold water. I've got detail down to tiny leftover scraper blade marks that were left on the master I was casting. From here on out, if a cast is bad, it's my fault. Haven't had any issues with reusability either.

Good to see the failures as well as the more successful methods and the pace of the video is just right.

Two part with the oyumaru type plastic is a little more involved than that; The first half of the mold you make is essentially a throwaway piece, so after making the second half, you redo the first one against the second one with the piece you're replicating lodged in it. Also, you'll get much better luck out of casting plastic pieces, rather than resin, since resin can soften/lose form when it's in contact with the heated plastic. Styrene has a higher glass transition, so it will retain shape well.

I've had good results so far by making sure the water is constantly hot by using a pan on the hob. Keep it just shy of boiling point and the oyumaru becomes extremely soft and it will take detail really well. I then use the lego frame/press technique to really get those two parts squished together. Also concur with others here suggesting putting in small indents or objects to act as a slotting guide for future uses.

I have used Instantmould (same as Orumayu and blue stuff), for reproducing parts with a lot a detail, problem is that you can’t press it using only your hands, because there is not enough pressure to make the mold plastic to really go into de details, try using the exact same method you used with the siligum, but instead of pressing with your fingers, use a plunger made also with Legos, and really apply a lot of pressure in an even manner onto the entire part. Once you have made this, then repeat the process with the other side, this way you make sure that both sides of the mold were formed using pressure. It also worth mentioning that miliput would be the best material for the cast. My main use is to make spare parts for models in really bad shape that can be found on ebay or by personal contacts, thus making a complete and restored 40k vehicle (tanks mostly), that otherwise could only be used as scenery. It’s much more work than making a new model out of the box, but that is just part of the fun.

The trick with oyumaru is to put it in what I'll call "mould walls" (essentially build a container like you did for the siligum) then apply huge amounts of pressure to the mould when you're making it

love the different approaches - glad you included the fails and missed attempts, great to see the effectiveness of each approach as you worked through them

I've been using Bluestuff, same as your Oyumaru and milliput mixed with greenstuff. You get the detail of greenstuff with the strength of milliput. The ratio does depends but useally GS/MP 1/4, maybe 1/3.

I've used Oyumaru successfully several times, you have to use smaller amounts at ome time and keep it extremely warm. After you've made the first half of the mold make sure it has completely cooled down before pressing the second half on otherwise you will distort the mold.

Interesting, as my experience with oymuru is very different, good quality and detail each time I've reused it

Will need to give those a try.

thanks for the demonstrated experiments!!

Dude I really like the Lego usage for the mold building what a FANTASTIC IDEA!!

Hi there, great video. The first time i bought Blue Stuff, i waste a whole pack of milliput to cast two decent copies of a LOTR Galadhrim elves. Actually, i have being trying to make a bigger mould with six miniatures in a round solid structure, to make moulds, and i got some news. None of them worked perfectly, due to the next problem. Imagine a pizza. Now, slice it into six parts. Each one of the slices, was one of my miniatures. When i put them under the presure, for the first half of the mould, everything goes great. The details, thanks to the solid structure of the mould, reveal themselves quite good. But there was the problem of the base of the structure. There is some weird balance to find, between how deep can you go into the mould pushing your miniature without breaking the base of it (leaks of green stuff or miliput) and the upper mould, going so deep that it´s quite hard to dismould the upper part without breaking it and getting al the good details. I think some "thick, but thin" base for the moulds, it´s a solution. Don´t really know why, the second half of the mould, always goes silly and without detail. That´s because i only make presure with my fingers. And i´m talking of the mould yet, not the reproductions. The moulds also need the finger pressure, and some heavy load over it for twentie minutes at least. I´m gonna try to make once again some good moulds, but figure by figure. I think i was too ambicious trying to have a circular mould of six figures to cast 36 miniatures in 24 hours (you know, at least 4 hours minimum to see results in miliput. PS: Great results come from putting your own weight canalised through your fists to the upper part of the mould. Hope this waterfall of thoughts in my terrible english turns usefull for someone out there!

Bluestuff (from green stuff world) is similar to the first product you tried. It works well but might I suggest the following: Using as little bluestuff as possible. Not to sure why but me thinner molds typically turn out better. Get in there with a toothpick/ sculpting tool to really get into ever nook and cranny When using milliput as a filler I have found that placing weight on the mold gets better results. I hope this helps!

Yeah Ive used the reusable mould before and had results similar to yours. I think liquid silicon moulds are still king. The semi soft/putty moulds just get into that fine detail.

I don't need GW anymore. 🙌🙌🙌🙌🙌