Rust conversion

[Rovcketman357]

Anybody have great experience with a rust conversion product?
Just bought a machine that spent a lot of time outside and it has some heavy rust on the cab and the attachments. Plan to wire brush and then treat with a conversion product before painting.

 

[Mike1955]

Wire brush is mighty abrasive. Someone hopefully has another suggestion

 

[Eagle1]

Rust conversion products need some rust to work, nothing done with good metal. Rust killers, etc can work by covering and treating.
I like Ospho for rust converter, thin to get into tight places and high rate of conversion. Seems like you get a nice hard product after it is done and dry. It does take longer to dry than others but I think it helps it work. Others may not see it that way.

 

[Topzide]

Black Star rust converters. Haven't used this product with great success and doesn't require a topcoat and just a pressure wash to knock off the dirt.

www.mrochem.com

$90 a gal and is just thicker than water and can be brushed, rolled or through airless sprayer (garden sprayer).

 

[KennyG]

As far as a rust converter, Ospho seems to work very well and is not expensive. I've never understood the advantage of paying more for a rust converter. It kind of depends on what kind of finish you want. If it's just surface rust and you want a smooth finish, you might want to touch it with a fine flap disc and then prime with a build up primer.

Note that Ospho recommends using it on clean metal also. I've ground the rust off things and then hit it with Ospho followed by a conventional primer and it's worked well.

 

[Mtsoxfan]

I've been using rustoleum rust converter, in a spray can for my truck. never liked Fluid Film and the like, drippy drippy, etc. 2 $6 cans do my whole frame and other spot rust. For me, it works well. Very little rust comes back. All I had was surface rust on all the welds on frame though. Truck is only 7 years old and driven in the winter.

 

[HawkinsHollow]

Ospho is phosphoric acid so it converts the iron in the steel to Iron Phosphate before the iron oxide(rust) can take hold. In the case of already rusted metal it converts the iron oxide (rust) to FePO4. Obviously it works best when you remove as much of the loose rust as you can by mechanical means. Somone commented it takes longer to dry, it has wetting agents that slows the dry time for greater conversion. Once it is dry the conversion process ends. I have used it with great success.

 

[weldingisfun]

Ospho worked for me.

 

[jaxs]

I like Ospho and it has a good following but I also buy Jasco on sale at Lowes for less than half the price of Ospho and it works equally well. I wire brush loose rust off before application of converter. If sanding sheet metal and auto body exposes bare spots I add 25% converter to wet sanding water.

 

[HawkinsHollow]

If sanding sheet metal and auto body exposes bare spots I add 25% converter to wet sanding water.

Well played sir, well played!

 

[nyone]

I have never had good luck with converters. If you look really close there prep is nearly the same as normal paint.

 

[varmint]

However you choose to treat the surface rust, after it's clean and dry, use a two part epoxy primer before top coating. I had a rusty (not too bad, though) 6' loader bucket I cleaned and primed before top coating with Kubota spray paint. After a couple year's use, some areas the top coat had worn off, but the primer looked untouched. Zero rust.

 

[LoudonNH]

Anybody have great experience with a rust conversion product?
Just bought a machine that spent a lot of time outside and it has some heavy rust on the cab and the attachments. Plan to wire brush and then treat with a conversion product before painting.

I keep a six-pack of little POR-15 cans on hand. It works well on both rust and bare metal and I simply discard what’s left in the can after about a year. It dries hard as steel and is easy to sand, fill and paint, as instructions say to topcoat with paint wherever there’s exposure to sunlight.

 

[CoyPatton]

Wire brush is mighty abrasive. Someone hopefully has another suggestion

Like all painting projects the details of finished results are in the prep. Loose rust material must be removed or it flake off, probably soon after painted if not during painting.
If your goal is simply to stop rust then a wire brush finish may meet your desires, if looking for a nicer finish, it is 1 step in a multi step process.

 

[neilpaku]

Like everyone else wrote, a phosphoric acid converter - I have a gallon of straight phosphoric acid which I brush on after removing loose rust. I bought a 120v needle scaler which makes life very easy but you might not want to use that on visible "shiny" surfaces. Someone mentioned Fluid Film - that's a hygroscopic product, not a rust converter, however, it's good for using after the surface is completed. What's even better is straight lanolin, which Woolwax sells. I covered my new pickup head to toe in it (not the outside shiny parts but everything else) and I'll re-up the underside that's exposed to road wash every few years. For the inside of gas tanks, I have used POR-15 and there's other similar products to do the same job, but again, after the inside has first been cleaned up. I've used citric acid for those jobs.

 

[Fxfymn413]

I like Magnet paint's Chassis Saver. Equivalent of Por 15, but less cost.

 

[Cycledude]

There’s a product advertised on Facebook that you just spray onto rusty metal and then rinse it off with water and the rusty metal looks brand new again, they even have videos so it must be true !

 

[Gord Baker]

Anybody have great experience with a rust conversion product?
Just bought a machine that spent a lot of time outside and it has some heavy rust on the cab and the attachments. Plan to wire brush and then treat with a conversion product before painting.

Surface Preparation is Key! Abrasive blast to 'near white' metal.
Apply zinc rich primer and top coat with high build epoxy.

 

[rocco611]

Rust converters work ok. It will slow down rust but not stop it. It will not penetrate all the way into the rust pits . It only converts the rust it can reach. Eventually the rust will come back , but it is better wire brushing painting over the rusty metal. The only way to stop the rust is to acid dip or sandblast then prime and paint. Every speck of rust has to be removed. I have fixed autobody repairs that were done with rust converters there was always rust in the pitted areas under the coating. The upside of most rust converters is that they are non toxic . I am not sure if it is still a practice but I remember a farmer that applied it to rust spots in gondolas once a year before harvest.

 

[charlessenf]

Anybody have great experience with a rust conversion product?
Just bought a machine that spent a lot of time outside and it has some heavy rust on the cab and the attachments. Plan to wire brush and then treat with a conversion product before painting.

I use OSPHO - get it at a Paint Supply Store.

I used it and NAVAL Jelly some years ago on a Datsun hood (engine cover) that had never been painted; the exterior / upper surface was covered in rust. I used up a bottle of Naval Jelly covering teh entire thing. I let it set overnight or more, then hit it with the OSPHO and let it set. Then, I primed and painted it. It held up until somebody stole it!

The OSPHO turns the rusty surface(s) dark/black, You can wire brush it first or after. The OSPHO needs to penetrate beneath ALL the rust - so I like to do it a couple times before primer and paint. Use an etching primer first, then - if the smooth finish is important, Sanding/'Sandable' Primer and go through the grits to get to a baby's ass smooth before painting.