Applying Rust Killer to under carriage /frame any reason not to ?

RabidScott said

I have used a product called "Ospho" to amazing success on my vintage Ford projects. Heavy duty gloves, stainless steel brush pads, eye protect and elbow grease.

Knocked all heavy stuff off and used Ospho to get a '32 frame to beautiful bare metal. The say you can paint directly over it but I'm not sure. The Rustoleum I applied over it is sticking quite well.

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Sorry, can't find any pictures of the process but it works great!


I've also had luck with a product called "Evapo-Rust" though the way it works it's better as a 'dip' and not a treatment.

Good luck!! View attachment 1715658866

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I have used Ospho for years. Be careful as IF you do not neutralize it with water you can get a delayed reaction with use of epoxy primers, or even stuff like Rustoleum enamel. I like it mail for pitted metal.
Get ride of all the rust you can with an abrasive. First. Don't go the rust convertor idea and changing a lump of rust into some inert whatever. If you use Ospho, apply a good wet coat. Let it dry at least a day, then use a Scotth brite, sandpaper, and get rid of the white phosphorous coating. If you want to neutralize it, wet again and let it sit for 10 minutes but not to dry. Then wash with water Dry with compressed air to keep down flash rust which really is not a problem if going back over with epoxy primer. Just my way. Your results may vary!
I like using a good epoxy primer. Seal that with any good single stage acrylic urethane. Or just Rustoleum.
NO need for expensive stuff like POR15. Rustoleum is just as good.