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Rust removal

Haven't used "ridrust" before but I have used "Ospho" before which is a rust converter and primer. Green in the bottle about like a thin soup, clear on application. Converts rust to a black phosphorous material. Be careful as some paints won't stick to it after you've applied it.
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Actually... the conversion left by Ospho if done correctly should be zinc or iron phosphate. If you keep the metal wet long enough it etches the good metal while dissolving the rust. The phosphate coating left behind should be of matte, grey, uniform appearance and is an excellent surface on which to paint.

Ospho and similar phosphoric acid washes aren't normally called conversion coatings. Yes, they dissolves rust and leaves a phosphate converted surface on the metal. However, what people generally mean today by a conversion coating are chemicals that act on the rust, partially convert it to a phosphate, and then cover it with a primer-like material... all in one step. Duro Extend comes to mind when thinking about hardware store stuff. Eastwood's Rust Encapsulator comes to mind when thinking about a more high-end converter/primer.

It's always better to remove as much of the rust as possible before applying any coating. The phosphoric acid washes are a good way to do that.
 
HI John, it is a bit late for you but one very good conversion product available at most body shop supply stores is called "One Step" gets hard as a rock and takes paint very well.---Keoke
 
I ended up using Jasco Prep and Prime which converts the rust and preps the metal. But these other products (Rid-Rust and Evapo-Rust) appear to be true rust removers and don't use phosphoric acid. Seems better to get rid of as much rust as possible, not just convert it.

Cheers,
John
 
Well John,That may be.However, the interesting feature of these products is some light surface rust must be present for them to work. No rust no convert.---Keoke
 
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