I have used cast epoxy
for things like mounting my primary winches (50 - 80mm thick epoxy pads). They see upwards of 1100 kg of load and handle it quite nicely.
I don't have any figures for what is typical but here is a link for one supplier.
Casting Resin Epoxy Casting Resin
8500 psi is about 1/4 of unwelded aluminum
, and 1/2 of typical welded aluminum
But that is probably for "neat" resin with little filler added. If you can, add glass milled fibers; you will increase the strength considerably. Longer fibers are stronger but make the part fuzzier until you sand it. Making it "chunkier" than the broken part if possible would be good too if dimensional issues don't prevent you from doing that.
I use cast epoxy for lots of serious load bearing applications but it won't be as strong as alum. or bronze so you just have to make it a bit bigger when possible.