Painting pitted sheet metal

Josh in Pa · Feb 18, 2014

I am painting a tractor that sat outside a lot before I got it. The sheet metal is rusty and pitted, but not rusted through or even thin. I plan to sandblast it, but am still worried that I won't get all the rust, and it will come back through. I am going to use epoxy primer, a filling primer if needed, and acrylic enamel. Should I use some kind of treatment before the primer?
Josh

Oregon Tractor Jack · Feb 18, 2014

I always hit the sheet metal with OSPHO which is a brand of phosphoric acid. I neutralizes the rust. It will turn the rust black. Read the instructions carefully. You need to let is set with a wet coat for time, then rinse. I also lighty sand the sheet metal after treatment to make sure I get good adhesion.

showcrop · Feb 18, 2014

2X the phosphoric acid. You are wise to be concerned, because the rust will continue to work in the pits. Your paint supplier will probably carry it though perhaps a different brand. if the pits are very deep I would suggest longer contact time.

GordoSD · Mar 6, 2014

Dupont "Metal Prep. Is phosphor product. Then skin the whole thing with body filler. Sand down with long board and 18o. Then high build primer, 3 coats at a time, sand with 360, until no waves visible. Wet down and look for scratches.

Painting pitted sheet metal

Josh in Pa

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Oregon Tractor Jack

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showcrop

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GordoSD

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