SteveUK wrote:The PVC sheet seems quite pricey, but I have an idea for the end caps - if it works this will be the final part of the jigsaw. My plan is to make up a basic end cap pattern and make a silicone mould for producing rough end caps.
I agree that plastic is very expensive, but it does machine nicely, and it's tough,flexible and resistant to moisture.
Plastic offcuts can be picked up very cheaply, but you need to be near a plastics outlet to benefit from this usually.
The resin idea will work, but I think you'll be happier with PVC, lexan or acetal caps in the long run. Polyester filler is just resin mixed with talc, and it does tend to absorb water over time, and I tend to find that polyester resin is rather brittle when it isn't mixed with glass.
You could mix some resin up with some fine ground glass, that would be very tough.