Recently someone messaged me on facebook asking if using oyumaru for molding around an existing face sculpt would damage the paint. I replied that it was relatively safe for painted parts and I decided to test that theory out. First of all I needed some assistants.
And of course, the Oyumaru.
Generally speaking Oyumaru is a sort of clay compound that becomes malleable with the introduction of heat. Interestingly enough, when the heat factor is removed the clay-like material retains it shape rather rigidly, resisting any deformations until it's heated again. as such it's an excellent material for 1-part molds, though some modellers have had success with 2-part molds themselves.
Now that that's out of the way we can mo--
...Stop it you two.
Okay, now you'll need hot water.
Dip the Oyumaru into the hot water and wait for it to soften. You can hasten the process by putting the water and oyumaru into a microwaveable container and heating it in the microwave for 1 minute and 30 seconds.
that should make it soft enough to knead into shape. Now to mold the original part you'll need to be very careful to get all the contours around the part. This is somewhat difficult to do with anything that isn't a flat shape, but we're too far into this post to let that in the way of showcasing comedic situations now, aren't we?
Let the oyumaru cool on its own (or run it under cold tap water to harden it) before removing the original part. Once the part is removed you'll have a useable one-part mold, but in this case it won't replicate the entirety of the part, only the front.
There is zero damage to the object you'll replicate so we should end this post here, but I wanna tackle the other part of the process.
Now the recasting material comes next but I lack any usable resin at the moment so we'll have to MacGyver our way on this.
Welp. Beggars can't be choosers.
whatever material you choose, make sure to mix it thoroughly so it sets in the proper way. For molds like this it's always recommended you use pour-able materials in order to get the best results.
Once the material sets it's just a matter of removing it from the mold. If you intend to make multiple copies you should be very careful in extracting the recast from the mold. Ideally, you will have designed the mold in a way that makes it easy for you.
If not, then simply re-heat the oyumaru again and peel the softened mold from the recast.
So did it work?
- Recasting material: In this case we tried material that wasn't appropriate for the mold design, that's something to consider. the effectiveness of the recast relies on this. Polyester Putty which is in the form of a paste has been used for molds like this by other modelers though it usually dealt with parts of flatter contours and hence easier to push into place. though you can succeed in face sculpt replication with polyputty over repeated tries. This tutorial was only a one-off thing.
- Mold design: We essentially made a pour mold for the piece what's more is the small entrance for the recasting material makes it difficult to get into nooks and crannies. In instances like these it's best to design the mold in two parts, so you replicate the front and back halves of the piece as separate parts and just assemble them into a single piece afterwards.There are many ways to go around this method of parts replication and success is 50/50. don't get discouraged by failing the first time because that's part of the process of refining your approach.I've had marginal success in replicating other things from oyumaru, such as this leg armor part for the Liger Zero:
See how that's a two-part mold above, and the material was epoxy resin.
The trick here is to study the object you're recasting before going forward, and since oyumaru is reusable with just a dip in hot water, you can keep trying without having to worry about wasting too much material.
I'll do a proper face replicating tutorial in the future but for now, I've filled my quota for Shinki abuse today.