Reproduction castings

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This is just a rant to make prospective reproducers of cast parts aware of the shrinkage inherent in castings. I had a hell of a time refitting the taillight bezels on my 840A convertible after a fender repaint. I finally ground a little off the inside lip, and put a higher tab on the fender nacelle to engage the slot in the bezel. When I ground the inside, it was obvious the material was brass, not the original pot metal. Aha! I measured the distance across the corners, and it was 1/8″ shorter than an original I had lying around.

Point being, the easy way to reproduce a part is to make a mold of it, and then use that mold to cast new parts. BUT-They will be smaller than the original part due to shrinkage as the metal cools. The correct way is to make a mold that is slightly bigger than the original part. If you’re gonna do it, do it right.

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