Silicone rubber tracks (3d printed moulds)

Making small vehicles is hard, and one of the hardest parts is finding suitable wheels. Most of the time, you either have to put up with hard plastic wheels, or hope you can find a toy to scavenge them off.

But the robotics community has a trick up their sleeve: silicone rubber moulding. You can 3D print a mould, fill it with silicone (and an accelerant) and have a custom tire that looks like whatever you like.

I wanted to make a tiny trak that actually had tracks, so I needed some tracks. Typically people buy lego tracks, but I didn't have any, and couldn't be bothered ordering them. So, here we have a way to make your own tracks.

So, to use the moulds:

1. Print them
2. Snap the inner mould into it's two halfs
3. Mix silicone with flour or cornstarch or icing sugar or glycerol. These act as an "accelerant" and reduce the drying time considerably. The more you add, the less grippy the track, the less you add, the longer it will take to set.
4. Fill the outer part of the mould with the silicone mix, pushing it into all the treads
5. Coat the inner parts of the mould with silicone, making sure everywhere is coated as thin as possible
6. "glue" the inner parts of the mould together with silicone, and wrap some polyester thread around it (this stops the tracks from being stretchy)
7. Push the two parts of the mould together. There are some alignment tabs to keep the inner/outer parts aligned. The inner mould should fit flush inside the outer.
8. Wait an hour or two for it to set
9. Remove the inner mould. If you use a thin piece of metal you can bend one half of the inner mould so that it clips past the other inner-mould-piece. By doing this you can avoid putting unnecessary force on the tread lugs.

I've also included an idler wheel and a drive wheel. They mount 42-43mm apart.

I plan to make an instructable in the near future with more details on how to make them.

Edit: I noticed an error in the STLs and fixed it a few minutes after publishing, however some people had already downloaded it. If you downloaded it within the first five minutes, you should probably re-download.
Also, the moulds aren't showing in the preview, but they are there in the files tab....