Ospho or etching primmer or both?

Working on the frame today. Wire wheeling away. It seems like the rust is mostly surface, it wire wheels off fairly eaisly. But I can't get into all the corners. And getting into all the body mount's is impossible. But I don't want to do this again.

So do I have to get every molocule of rust off the frame?

I was going to use and etching primmer then I started reading about ospho (phosphoric acid) as a rust converter.

So then I started thinking aobut using the oshpo first, then the etching primmer, then a topcoat.

But are the ospho and etching primmer doing the almost the same thing? Does an etching primmer convert the rust in the "etching" process?

So do I use pholphoric acid (was going to us in the frame anyway) only? Etching primmer only? Or both?

Thanks.............

 

Hi , I would use a product called POR15. It comes in pints quarts and gallons , it can be sprayed on or brushed on. It is made to put on over minor to moderate rust.This stuff will seal it off forever. The only thing is it has to be topcoated or the POR15 will break down over time. It is available in flat , satin or gloss black as well as other colors I think. For your wire brush frame this is the best way to go. The company website is www.por15.com. I have used this before with great results. Let me know if you have any questions.http://www.por15.com/
Paul

 

I believe what causes POR 15 to break down is exposure to UV light (sunlight). Probably don't need to topcoat a frame unless you plan to spend a lot of time upside down.

 

Pretty sure the etching primer requires bare metal. It's acidic, adding 'tooth' to the surface of the metal by exposing the edges of the steel grains chemically. Epoxy primer is equally effective AFAIK.

I've used Eastwood's "Rust Encapsulator" with good results. It and POR-15, plus several other similar products, can be applied over tightly bound rust (ie no flakes, wire brushed) and are supposed to seal the rust from air to stop the rust.

 

Thanks for the info guys. And the recomendations. But FWIW, I've decided against the Por 15 and like products. I want it repairable when needed. I know the frame will get scratches and scrapes. And no one will commit that the Por 15's and the liek are easy to repair. I'm also wondering if I got a scrape on the underside of the frame, expoxing metal, would the rust begin to run under the coating since there would be a brake in the air and moisture barrior.

But I am thinking of a hard topcoat. a 2 part or something. The dude that sells the finishes I use in my shop has some good recomendations. He is the one that sold me the etching primmer. He said nothing was needed but clean metal. But I can't get all the rust in all the locations.

But anyway, with the ospho and primmer, use both? Use ospho and no primmer? Use Primmer and no ospho? What would be the exact 1,2,3 steps to use?

I searched but could only fine info on phosphoric acid or primmer. But none used together. Howerver, I did get a google hit on a hot rod site that said: wire wheel - ospho - sand (no girt noted, but what, 220?) - second ospho - sand (girt?) - prime with sandable etching primmer - sand - primmer again - sand - topcoat. Course that was for a hotrod show frame.

I only want long lasting, eaisy to repair.

I am going to spray down the inside of the frame rails with ospho and let it be.