Moulding techniques for SlotCar wheels

1. Turn a series of master hubs out of aluminium, (taking into account the regulations on sizes).

2. Mount these onto an open box. It is possible to stick these down with superglue or any adhesive e.g. double sided tape.

3. Mix and pour the RTV silicone rubber into the box.

4. After 12 hours remove the mould and pour PU's into the mould.

5. The replica parts should be cured within 20-30 mins depending on the grade of PU used. Using the pigments on there own or mixing them can result in some interesting colour combinations as shown below.

Note: If the PU starts to foam once it has been poured it will mean that there is moisture in the mix and the final pieces will be slightly spongy. If this is the case mix a new batch of resin and re-pour.

Silicone Tyres

This is slightly more complex but once you are aware of the process any parts can be made from silicone. The important part is that the mould should not be from silicone but another material, e.g. aluminium, or a high density modelling board. I would not recommend using a wooden mould as the material is too pourous and will leave marks on the finished pieces, and may stick. (The example below uses modelling board pre cut to 40 x 30 x 300 mm)

1. Drill a series of holes through the block as shown.

2. Cut the block down the length and then bolt back together.

3. Using a flat bottomed drill and the cut line as a centre drill out the outer dia for the tyre.

4. You will need to make up a series of internal master pieces that will fit into these holes.

5. Fit all of the pieces back together using wing nuts on all of these bolts for ease of releasing.

6. Mix and pour the RTV silicone rubber with a pigment into the mould and leave to cure. After 6 ­ 8 hours it is possible to de-mould the jig.

Examples below are from the jigs and tyres from the D&T show 2008