To make a long story short...
I'm designing a 48x36 router, stainless steel shafts, linear bearings, etc.
After pricing aluminum shaft supports, I'm toying with the idea of creating a silicone mold and using polyurethane resin to create the rails at a much lower cost.
I think it will be strong enough. It will be bolted to the shafts and to a steel frame. It will there simply to keep the shafts from deflecting.
Has anyone tried this stuff for structural components of a router?
If it fails, I can always reuse the silicone mold and try my hand at lost wax casting with aluminum