Insertion cast wheels

On Wednesday, I managed to get away from the Christmas concerts for a meeting of the North Shore chapter of the local NMRA division. It was Graham Stokes’s annual “Trains and Scones” evening, and as usual he had a little table to show off progress on our current projects. I wanted to show the wheels, and so, despite castings still only getting vacuumed, I finally tried putting the plan together for a test run.

Rather than experiment on one of my hard-won metal wheels, I cast the spokes into a resin casting. Starting with a decent resin casting of the wheels, I cut out four of the eight spokes in the small wheels and all but three spokes in the drivers. I painted the modified casting black so it would contrast the cast spokes from the inserted spokes.

I coated the treads with Vaseline and then poured resin into the moulds. Wearing nitrile gloves, I pressed the modified castings into the wet resin, and vacuumed out all the bubbles.

The wet resin was an effective paint stripper and I could see the paint flowing everywhere, turning the new parts as black as the old. I believe it may also have disrupted the resin itself as some of the spokes were too fragile to demould. The driver was unusable, in fact.

However, when all the bubbles were out, and the new castings had set, I removed the two smaller wheels from the mould, and they each had their spokes restored, except one that broke during removal. I think I will try it one more time without the paint before I declare victory over the process and start making wheels for real. It’s looking promising!

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