[Riot Racing]

Originally Posted by Dave C.

IMO, After looking at those wheels, I would wash them with phosphoric acid, scuff them, then spray your epoxy. I have a bunch of parts that were sandblasted and then powder coated which are spider webbing all over. I don't believe that sandblasting removes the rust, it only removes the loose material. Oxidation is a chemical reaction to the iron. Pitting reveals the problem as an embedded problem to the steel piece.

Well ****! I wish I had this post before I sprayed the primer on the wheels

[diety motorsports]

as long as there is no rust left. and was dry and covered with a dtm epoxy. the rust cannot come back. if sealed properly. I would not worry about it at this time.

[Dave C.]

Don't worry, If you look at the spec sheets and MSDS for most DTM primer/sealers, they use phosophuric acid to assist in etching to the metal. I just prefer the extra preperation steps to ensure the rust has been stopped.

[deadbodyman]

Hey Dave, what do you use straight phosphric acid or is that the main ingredient in the product you use.....like my Ospho I love so much....

[Dave C.]

I'm pretty sure the Ospho must be the same as the Rustmort by SEM, I had been using for years. Over the past couple years I have been using a few different products yeilding the same to very simular results. I find that the most effective products like the rustmort are approximately 75% phosphoric acid. Recently I've used some stuff at my local tractor supply store as well as POR's metal ready, all with the same results. I have even used concrete etcher with simular results. Now I just try to find the most cost effective product as most the items I am working on are/were rusty. I also like to wipe off pieces that I have welded with something to help neutralize the oxidation left from welding. Plus areas that are welded contain more iron than the mild steel pieces usually welded, therefore more susceptible to corroding faster. Many cars that have been brought to my shop usually are rustier where they were previously repaired!