Rust converter

I've just got around to using some rust converter and it's behaving not as expected. I applied it to a couple of pieces and let it dry overnight and it dries into a clear film that can be washed off with water???
The pieces had only small amounts of tight rust as I had got it cleaned off pretty good with a wire wheel. I guess I was expecting this stuff to dry film free like an alchohol leaving a powdery residue if it encountered some rust. The product that I'm using is Ospho. This sound normal?
 
Usually the rust converter I use will dry and look very black and hard. I use it once in a while on stuff I don't have time to prep well and/or will need to topcoat. I can't comment on Ospho. I've used Permatex and Rust-Oleum brands. I would be skeptical of the product if water washes off a film of the product.
 


it is not the one that I use but Ospho appears to be the leading brand. What you describe is how mine works, except that the instructions tell you to brush it a few times over 15 minutes. After fifteen minutes I wash the piece off to cut down on the amount of white powder residue. Any residual, and you should always have some, is going to wash off easily.
 
I finally tried Ospho on a few small parts. I applied it with a small foam brush and what ran to the edges dried to a blackish bead like when paint runs. I wired brushed the heavier coatings and primed and painted over it as some here suggested. Not thrilled with it. Maybe if I sprayed it on in a lighter coat?
 
I m with you Mike. I have had it recommended but that white flake sure has messed with some of my painting. I have tried epoxy primer over it and it started breaking down 5 yrs later. Last time I let it dry and then lightly scotch brighted it before priming and painting. So far so good.
 
(quoted from post at 06:33:22 03/27/23) I finally tried Ospho on a few small parts. I applied it with a small foam brush and what ran to the edges dried to a blackish bead like when paint runs. I wired brushed the heavier coatings and primed and painted over it as some here suggested. Not thrilled with it. Maybe if I sprayed it on in a lighter coat?


Not good procedure!
 
I dont remember what brand I was using but it stated to lightly wire brush the rust and dont use on clean metal. Chemical reaction that only works with rust. If you cleaned it real well an epoxy primer would have been the way to go.
 
I've used Ospho/Phoscon for many years. I think it stands out on very rusted iron and on hard to reach places. It sprays on like water and works into cracks and places a primer cannot reach killing the rust. Yes, the white powder is an issue, do the best you can to remove it. Example, my dozer, I might work all day or only an hour cleaning, sanding, wire brushing and scraping, then spray Ospho on the whole thing. Some parts may get 4-5 coats. A gallon will go a long way. In the end, I remove any powder, prime then topcoat, using high quality paint.
 
I've just got around to using some rust converter and it's behaving not as expected. I applied it to a couple of pieces and let it dry overnight and it dries into a clear film that can be washed off with water???
The pieces had only small amounts of tight rust as I had got it cleaned off pretty good with a wire wheel. I guess I was expecting this stuff to dry film free like an alchohol leaving a powdery residue if it encountered some rust. The product that I'm using is Ospho. This sound normal?
I restore vintage FORD tools and used to use a rust neutralizer called EXTEND but they change that after a few years. After cleaning and getting down to bare metal - never sand blast - apply the EXTEND then after 24 hours its ready to paint. You apply it in three steps a few minutes apart. AS it dries it oxidizes and turns black. EASTWOOD PRODUCTS also makes a product but I've never tried those. EXTEND is made by PERMATEX. There two types of rust, or oxidation, of ferrous metal. Fe203, Yellow or Brown/Red Oxide and Black, Fe304. Red Oxide is what we see and call rust on iron. BLACK OXIDE is used to treat iron and will neutralize it so it does not continue to oxidize. Note hardened steel gages like precision bore rings and such have black finishes. BLACK OXIDE will not cause red oxidation as it is now rust free. There are a few places that sell rust treatment products - PERMATEX LOCTITE EASTWOOD...

RED OXIDE = BAD
BLACK OXIDE = GOOD


EASTWOOD PRODUCTS:

Tim Daley (MI)
 

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I restore vintage FORD tools and used to use a rust neutralizer called EXTEND but they change that after a few years. After cleaning and getting down to bare metal - never sand blast - apply the EXTEND then after 24 hours its ready to paint. You apply it in three steps a few minutes apart. AS it dries it oxidizes and turns black. EASTWOOD PRODUCTS also makes a product but I've never tried those. EXTEND is made by PERMATEX. There two types of rust, or oxidation, of ferrous metal. Fe203, Yellow or Brown/Red Oxide and Black, Fe304. Red Oxide is what we see and call rust on iron. BLACK OXIDE is used to treat iron and will neutralize it so it does not continue to oxidize. Note hardened steel gages like precision bore rings and such have black finishes. BLACK OXIDE will not cause red oxidation as it is now rust free. There are a few places that sell rust treatment products - PERMATEX LOCTITE EASTWOOD...

RED OXIDE = BAD
BLACK OXIDE = GOOD


EASTWOOD PRODUCTS:

Tim Daley (MI)
All of the information that I see on the various Iron Phosphate rust converters tells us that the black is iron oxide that has been converted to black iron phosphate which is the same as the coating on various tools and on some nuts and bolts. I used the Extend 25 years ago, but after a few years decided that it wasn't getting the job that I wanted done. In 2015 I bought a quart of SEM's Rust Mort. I used it extensively on an old car that I was restoring. Following the instructions to brush on; agitate with the brush periodically for ten minutes; then rinse thoroughly, I got black where there was rust and clear that dried to white powdery where there was no rust. Rinse THOROUGHLY after ten minutes.
 

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