The Stovebolt Site Forums The Shop Area Paint and Body Shop Rust, Primer, Paint and Prep

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.

Unfortunately, time can't substitute for some of the tools. Invest some of your time into something that will earn a little cash so you can buy a compressor or befriend someone who has a compressor and barter out some of your spare time for it's use. A cheap pressureized sandblaster from Harbor Freight will accomplish the tasks you need to complete one vehicle at minimum. Rust removal before using an encapsulating (conversion) chemical is essential.

Prep is the key, if its a house, car or the wife's nails. If it aint clean it wont stick! Find a compressor or rent one from a tool rental place along with a commercial sandblaster, or find someone who has one that u can use. Go to IRSauctions.com (not the FEDS) they have auctions all the time, online, and you can pickup an air compressor for 2-8 cents on the dollar! Only catch - you have to go get it.
Good Luck!

Good information! I have about 4 compressors laying around, but none of them are very big. A couple of 5ga, a pancake type and another smaller one. They're great for working around the house but not much else.

Guess I'd better go shopping!

Actually, let me amend my statements from above. Since I posted that thread originally, I have done some more research, acquired some more equipment and have attempted to educate myself a little more. Here's where we are in the grand scheme of things:

* I dragged out my biggest compressor, serviced it and prepared it for heavy use. It's not very big, but it seems to be doing the ob so far. I just have to remember to let it catch up every once in awhile. In this case, it's a good thing I'm not very fast.

* I bought a Soda Blaster at Harbor Freight and a 50lb bag of soda. Works well on painted chrome without damaging the chrome. Works well on small parts. I built a "cabinet" out of a heavy cardboard box so my media doesn't get everywhere.

* I bought an air-powered 6" orbital disk sander and some 80 grit adhesive paper, and tried my hand at sanding. MAN! You had better be ready for it when you pull the trigger! That thing takes off paint, rust and your first layer of skin FAST!

* I bought a few rattle cans of Rustoleum primer, to protect the areas I have sanded, just to cover them until I can get to them with something better.

Now that I have stuck my big toe in the water, I'm shopping for some additional things. This stuff is addicting!

Cool! Sounds like you're getting a handle on it. I like your approach with the cardboard box. It would be great if you could post some pictures on here. Clean metal is happy metal when it comes to primer and paint adhesion. And yes; it is very addictive.

I promised some others a few pictures of some miscellaneous stuff and will be sure to include those as well tomorrow.