Originally Posted by
roughkype
Varnishing the steel would protect you at the outer surface, but not if any moisture managed to wick in past the wedge. Plus, you'll have your blade resting on the hinge pin. If the blade hole is big enough for a brass sleeve that might reduce your trouble there. You can also treat the tang and hole with tuf-glide for some longer-term waterproofing.
I don't know how fast this corrosion would happen, just that it would eventually. If it gets bad you can always re-pin it then.
I've seen extra-hard copper wire for special wiring applications, "hard drawn" they called it. It has much greater tensile strength and is probably what you want for your rivets, if you go that way. Might be hard to find in 1/16" diameter. Do you have a source for it?