Posted by Guy Pasco on April 19, 1999 at 20:30:31:
In Reply to: What's all this black stuff?? posted by Michael Kirby on April 19, 1999 at 16:57:30:
Sounds like Ospho, which is an acid that changes rust (iron oxide) into inert iron sulfate. Ospho will also etch the steel to give the paint improved adhesion to the metal. The paint manufacturers also make their own conditioner products, rust converter paints, similar to the Ospho. Over here, the hardware store sells Jasco, which seems to be the same as Oshpo.
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