Rust Converter Recommendations. Aerosol for sun faded/surface rust car.

[plymouth67]

I bought this for a project at work. This stuff is absolutely amazing !!!

 

[Cal Tonsley]

Phosphoric acid converts rust (orange oxide) to black oxide that creates a barrier to further corrosion. That’s what the POR products use to achieve their results.

Just spray with phosphoric acid in the nooks and crannies and carry on.

Yep, that’s what I use, cheapest best option is to just buy a large container of Phosphoric Acid!
The (originally very rusty) exhaust manifold below was cleaned up with nothing more than phosphoric acid, rinsed and finished in satin clear heatproof.

 

[moparmandan]

My goal was to find a chemical converter. Spray, or brush it on, and brown surface rust turns black. That's all. Combine that with sanding, and end up with a good starting point for priming and blocking. That's all.

I've used the rattle can rust converter (and brush on Ospho) on the back side of rusty bumpers. Then followed up with primer and top coat. Works great there. On a hood or roof? I don't know. As others have said, rust converter products turn rust, or iron oxide, to iron phosphate. Have no idea if that's a good base to do quality body work.

 

[Phreakish]

Phosphoric acid converts rust (orange oxide) to black oxide that creates a barrier to further corrosion. That’s what the POR products use to achieve their results.

Just spray with phosphoric acid in the nooks and crannies and carry on.

That will work, but phosphoric acid makes iron phosphate, not black oxide. Black oxide is magnetite and is formed with a salt, not acid. Black oxide passivates the surface by oxidizing the surface and tying up the free iron.

Phosphate is a conversion coating which creates a physical barrier which is not an oxide, but instead a crystalline layer. It makes a better primer and sealer than oxides do.

 

[pt70]

I've used the liquid Rustoleum shown by Johnny Mac in post # 16. It works well. I prefer 'Extend' a little more. {napa, I think}. Tried the spray stuff, not as effective.

Cal; the outer nut (on the back and front of the exhaust manifold) is upside down. The split tapered side of the nut goes into the washer with a matching taper. This limits the pressure squeezing the manifold to the head. The manifold must 'float'. ----- Beautiful workmanship ----

 

[barbee6043]

Phosphoric acid converts rust (orange oxide) to black oxide that creates a barrier to further corrosion. That’s what the POR products use to achieve their results.

Just spray with phosphoric acid in the nooks and crannies and carry on.

I agree but be careful coming back with an epoxy primer that an react to the acid. Call Southern Polyrethanes and they will tell you that a reaction can occur with their epoxy primer. They recommend if using the phosphoric acid sol. (Ospho), then wet it all down good again with the Ospho and follow right up with a water bath to neutralize the acid.
I am no chemist but I have also been told in other places, the the reaction might occur of the epoxy prime contains any acid. I really have NO idea if any epoxys contain any acid!!!
I had a rusty hood a few years ago, I hit it with a DA 80 grit, came back over it with a big wire cup on the right angle grinder, there was pitts (rust) in the metal. I wiped it down good with Ospho. DID I let it dry overnight???? Don't remember. I coated it real good with Plain ole Rusteolum , the real stuff in the Gal can. After it finally cured, there ere some places the R. enamel sorta wrinkled. It sat outside for months, the R. kinda faded as usual, but it all was stuck on there like ugly on an ape. Point is, there was some reaction between the Ospho and the R. in a few places, and it all was darn near impossible to sand off when I later tried. Interesting experiment.

 

[my5thmopar]

I agree but be careful coming back with an epoxy primer that an react to the acid. Call Southern Polyrethanes and they will tell you that a reaction can occur with their epoxy primer. They recommend if using the phosphoric acid sol. (Ospho), then wet it all down good again with the Ospho and follow right up with a water bath to neutralize the acid.
I am no chemist but I have also been told in other places, the the reaction might occur of the epoxy prime contains any acid. I really have NO idea if any epoxys contain any acid!!!
I had a rusty hood a few years ago, I hit it with a DA 80 grit, came back over it with a big wire cup on the right angle grinder, there was pitts (rust) in the metal. I wiped it down good with Ospho. DID I let it dry overnight???? Don't remember. I coated it real good with Plain ole Rusteolum , the real stuff in the Gal can. After it finally cured, there ere some places the R. enamel sorta wrinkled. It sat outside for months, the R. kinda faded as usual, but it all was stuck on there like ugly on an ape. Point is, there was some reaction between the Ospho and the R. in a few places, and it all was darn near impossible to sand off when I later tried. Interesting experiment.

This is what happens to a nice paint job, when and it will, rust comes back. I’m my case the acid in the epoxy primer was incompatible with the rust killer. I used all body shop supplies from our AkzoNobel supplier. I’ll never use it again on a body panel. I would use it on other surfaces.

 

[barbee6043]

This is what happens to a nice paint job, when and it will, rust comes back. I’m my case the acid in the epoxy primer was incompatible with the rust killer. I used all body shop supplies from our AkzoNobel supplier. I’ll never use it again on a body panel. I would use it on other surfaces.

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I have mentioned many times that an epoxy primer CAN have a reaction with an acid like Ospho, which is a phosphoric acid solution. A second coat neutralized by water is the answer there. I was first told this by the man at Southern Polyurethanes. I have tried to say on here also, there is also a difference in auto cleaning acids types and "rust convertor".
Just wondering , did you use an acid product to clean the metal or a rust convertor. But like you said, he problem will arise IF there is an acid in the epoxy that reacts to the acid cleaner. Just wondering.

 

[my5thmopar]

I have mentioned many times that an epoxy primer CAN have a reaction with an acid like Ospho, which is a phosphoric acid solution. A second coat neutralized by water is the answer there. I was first told this by the man at Southern Polyurethanes. I have tried to say on here also, there is also a difference in auto cleaning acids types and "rust convertor".
Just wondering , did you use an acid product to clean the metal or a rust convertor. But like you said, he problem will arise IF there is an acid in the epoxy that reacts to the acid cleaner. Just wondering.

Industrial rust converter similar to Corroseal. However the pretreatment wipes the supplier gave me for final wipe down did good on the cab. I guess if it’s pitted, you have to blast or repair. I’ll not use it again on body panels. My 2 cents.

 

[barbee6043]

Industrial rust converter similar to Corroseal. However the pretreatment wipes the supplier gave me for final wipe down did good on the cab. I guess if it’s pitted, you have to blast or repair. I’ll not use it again on body panels. My 2 cents.

Pitted metal? I have many times used a big wire cup on my right angle grinder, to try to clean such best I can, I clean the rust dust off, and wipe it down good with Ospho , to be safe, wet again real good with the Ospho and neutralize it with water, air try to keep away flash rust, I give it a day to be sure it is dry in any crack or crevice, and epoxy prime. Never had a problem. Only other way to work that pitted metal would be blast with an abrasive that does not work it. Roofs would work pretty quick I bet.