I have been hunting high and low for tires for the 1:43 scale car and only finding plastic display model type deals or ones with really strange thicknesses of the tire itself. So after an excellent suggestion by a friend to try use Sugru putty for them I decided to give it a go. I'd need a mould to cast them so I designed a 2 part mould where the bottom plate contains the wheel hub shapes at 8mm thickness for the rears and 5mm at the front - hence the step down.
[5] 2M * 15mm hex slot bolts pin it in place aligning the the 2 parts up for an equal 2mm space all round each tire. I know in advance I will have to trim the tops but the hope is when I pull the bottom it'll bring the tires with it so I can slide them off each hub post.
Print settings
- Resolution - medium (default)
- No brim or raft
- No supports
- 30% fill density
Click here to download the "tyres_mold.zip" containing tyres_mold.stl for use.
The two part design is very easy to follow if you need to tweak or replicate. Both parts can be printed at the same time side by side.
It took a total of 2 hours to print the parts. I did not need to do any post print trimming, only needed to pilot drill out the bolt holes for a cleaner path.
When bolted together the two parts are solid together but I do not dismiss the possibility some material may escape the bottom. I could dig out out a bunch of G clamps to help pin it but I don't think they'd be required in this scale. If you scale up the design then it would be worth using clamps to save wasting material that escapes the bottom.
Sugru came in a pack of 3 each 5g weight.
It recommends storing unused/unopened packets in the fridge to triple the shelf life.
This can be used for moulds but given it'll stick to anything you need to coat with Vaseline or grease paper or similar. I am using lip balm as it better stays in position and fills all the print lines.
I switched to using screws for the corners to better pin the parts together. Now ready for use.
Working the Sugru into the mould is not easy as it has nothing to grip on to stay in place. The best method is to use the end of your finger to force it in and smooth it off, keep repeating all around until it begins to bulge out. Once it is bulging out use a bit more to scrape over the top to ensure it's fully filled.
Repeat for all 4 wheels which uses the whole pack with a bit excess on the top. This means 3 sets of wheels per Sugru pack or at this time £2 per set of 4 wheels.
After 24 hours of waiting I trimmed the tops with a surgical knife as flat as I could. The lip balm seems to have worked excellent as there is almost no bonding to the mould at all.
This is where I really find out if it works, unscrewing the mould parts and carefully working my way around the seam opening it up a little more at a time until eventually the bottom came loose leaving the tires in the top section opposite to what I was expecting. If I had to guess I'd say its the greater surface area on the outside of the tire providing more resistance than the inside hub.
The tires pushed right out of the top mould section without a problem. The inside and outside of all the tires are excellent. One steering tire has a tiny bit missing about 1mm deep but its not a problem.
Finally the tires fitted on the newly painted white rims. I used UHU glue to bond them on as its easy to rub off if they don't work out.
I'm very happy with the result but proof is in the pudding as they say. Watch out for the 2nd part of the 1:43 scale - 3D printed RC chassis for FPV micro racing when they'll be put to the test!
3D printed tire moulds for 1:43 RC cars using Sugru
