I posted a question on another thread, and I'm afraid I accidentally hijacked the original questions. I asked:
Thanks 5wests..........I've been trying to do some further research, but confusing myself with conflicting information. For instance I have read:
* You can brush, spray or roll epoxy primer
* Epoxy will "encapsulate rust" (you can prime right over it)
I know it would be preferable to spray over bare metal, but I don't have the facilities or capabilities (or $$$) to do it that way.
What am I going to lose if I brush on epoxy primer over light rust?
jomichael responded with:
As far as I know epoxy primer is not a rust encapsulator. Rust encapsulators have chemicals that change the composition of the rust, making it inert, then seals it from moisture. Epoxy seals really well, but the rust is still there in its original state.
I don't recommend spraying or rolling epoxy over rust. Take the time to remove the rust.
You've got to have the capabilities and at least enough money to get some sand paper, a grinder with a wire wheel, and some rust converter? All it is is labor, and that is the most valuable thing you have in this hobby
And tclederman chimed in with:
Fiftyfifty took his thread in a different direction.
In answer to the original post, many people extolled the virtues of epoxy primer over clean, rust-free, blasted metal. They are correct - epoxy primers create a water barrier against exterior water reaching the metal surface.
jomichael is right about epoxy being of limited usefulness when applied over rusted metal. And, "rust encapsulators" are of limited use when applied over clean, rust-free metal (and/but, loose rust should first be removed.
Most (all?) of the "rust encapsulators" use water as their "hardening catalyst" - water and water vapor above and below the layer of paint help to harden the paint. The resultant paint surface is impervious to water transfer.
After curing, epoxy paint and water-hardening rust-encapsulator paints need different special preparations when applying over-coats of any paints. The overcoat paint company might have specific instructions/warnings for use with either type of undercoat.
All that has helped me out a lot!
When I was speaking of not having the ability or equipment, I was speaking of the specialized stuff. I have access to all the sandpaper, wire wheels and small stuff, just don't have the welder, monster compressor or air powered tools.
One thing I DO have is time.
Thanks again guys.
