Mastercoat Surface Prep

“Leave some of the rust on, it works better that way.”

No, not really.

Other companies will have you believing that applying the black moisture cured urethane over rust helps it adhere better. In reality, initially it will adhere better over tight rust. Black moisture cured urethanes are not airtight so the rust under it continues. At this point you can peel it off in sheets.

The proper procedure is to sandblast the surface or grind it up to create a anchor pattern for the paint to adhere to. Some companies recommend 80 grit. This is too coarse for my taste, so I preferred 180 grit. The reason being, if you use ordinary paints and primers, sand swell marks could come to the surface and ruin your paint job.

What I recommend and I have done for years is a good metal prep. This is a phosphoric acid compound that will dissolve the rust in the pores of the steel and leave a zinc phosphate film to prevent further rusting. This is the old industry standard and worked great for decades. I like to combine both. By using the metal prep and sealing it with an airtight primer, there is nothing more that I could possibly think of to combat rust.

Mastercoat Rust Remover/Metal Prep is a fast acting rust remover that will dissolve the heavy surface rust within a hour. Mastercoat Metal Prep leaves a zinc phosphate film to prevent corrosion and promotes paint adhesion. This method is excellent also for storing parts in doors for months rather than using spray can paints.

To prep the metal before applying Mastercoat Permanent Rust Sealer, nothing is more effective than our Metal Prep for a long lasting paint job. If you have any questions about application, please contact us.