To make my katana molds, I did the following:
- Carve each half of the katana out of foam
- Glue these foam halves to a foam base
- Coat the foam halves with fiberglass
- Use acetone to melt away the foam base and blades
This idea mostly worked. However, the fiberglass was slightly thin in areas, so the molds tend to twist a bit, and the foam left behind “sludge” (the dissolved residue) in the molds that is taking quite some time to clean up. I could get a wire brush for my dremel to help, but it will still take a while. I’m not terribly upset by this – it was a test run.
For my next attempt, I’ll glue the foam blades to a plastic sheet, and use vaseline on the blades and plastic to keep the fiberglass from sticking. This should let me reuse the foam blades, assuming I coat them well enough with vaseline, but still get the details I want in the blades. That, with another layer or two of fiberglass or resin, should give me what I need.
This will probably have to wait for the weekend, though, as I don’t have much time to work on such things during the week. Carving foam is kind of noisy, and even with soundproofing precautions I want to make sure I don’t annoy my neighbors.