I am striping my 1/4s to sheet metal in order to remove surface oxidation and old finish. My question is that as I remove the rust its most outer layer would be reddish brown color (natural rust) and as I remove more the color changes to black. This black stuff still is rust, correct?
How do I remove ALL the rust to ensure that some years down the line it wont start to rot the sheet metal below the finish?
Could I shoot a coat of thinned POR-15 then an epoxy-primer over that or will epoxy-primer alone suffice?
What is the best approach?
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