I know what you’re thinking: ‘What the heck is oyumaru?’ Well, you’ve come to the right place!
Oyumaru is a Japanese molding compound, used to make or copy little objects. Sounds fun right?
So, I bought these small reusable oyumaru-sticks. I think the small packages were €1,25, quite cheap for a small experiment. In room temperature, the oyumaru-sticks are stiff, but when put in hot water, they become more flexible. This also means that if you want to reuse it, you just need to heat up the material again.
Eager to try the sticks, I used the first thing I could find to make a mould. And that object was this bottle cap of a perfume bottle. I wanted to see how much detail can be copied with these sticks, and the lion on the bottle cap has some small features.
1> Fill a cup with (almost) boiling water. Make sure an oyumaru-stick would fit in completely.
2> Put one (or two, depending on object size) stick in the cup.
3> Use a spoon or pincet to feel if the oyumaru softened enough.*
4> Pour the water into a different cup so you can grab the stick.
5> Wipe with a paper towel or a cloth so the oyumaru is not as wet anymore.
6> The material is now really flexible, mould it a bit before pushing the object in the material.
7> Let it cool down for a minute or two. Then you can easily remove the mould from the object.
*On the packaging is shown how to use the oyumaru, but i’d really advise against using a pincet to pull the stick out. Because the stuff gets really flexible, you just rip off little pieces of the material instead of pulling it out the water. And because the water is still hot, I advise to just pour it in a different cup and use your fingers to get the oyumaru out off the first cup.
After all these steps, this was my result:
I was surprised with how detailed the mold turned out to be, though there are some holes on the top.
Now, this mold is reusable, so you can make different copies of the object. One of the materials you can make a cast with is, believe it or not, oyumaru! To do this, just repeat the process but instead of pushing the object in the oyumaru, you push the stick in the mold.
This was my cast. It is not really visible on the photo, but it has a very ugly line right through the lions mouth. I guess it’s because there was air trapped between the two materials, but I’m not quite sure.
Note that you don’t necessarily need to use another stick oyumaru to make the cast. You can use resin or plaster, something I look forward to trying. If you want to make more complex parts, this bloggers post can be really helpful!
+ Very easy to use
+ Relatively detailed results
– Small ripped off pieces cannot (easily) be reunited
– Only for a small series of casts
– Trapped air can give bad results
Luckily, practice makes perfect!