Which Rusty Metal Product To Use ?

[Conaway2]

I’m reconditioning a pair of ‘29 running boards that have some surface rust on them. I’ve wire-brushed them pretty aggressively and treated them with Rustoleum Rust Reformer. I’m considering using either POR-15 or Rustoleum Rusty Metal Primer as the next step, but leaning toward POR-15 as it leaves a very tough polymeric coating when it dries.

What products have others used in a case like this where sandblasting is not readily available to me.

Thanks,
Jim

[1crosscut]

Try soaking them in a solution of water and Oxalic Acid (wood bleach) available in powdered form from any hardware store. Does a very good job of dissolving rust and is fairly cost effective.

[updraught]

Australian Standards say rust converters don't work ...

"But, according to Standards Australia’s “Guide to the protection of
structural steel against atmospheric corrosion by the use of
protective coatings”, AS/NZ2312:2002, “There is a considerable
amount of published literature which refutes such claims, stating
that where any conversion may occur, complete penetration of rust
and reaction with it is unlikely.” Standards Australia declares that
with some ‘rust converters’, only a colour change occurs, whilst in
the case of phosphoric acid-based rust converters the phosphoric
acid has little or no reaction with hydrated ferric oxide under normal
conditions, and that unreacted acid can become trapped beneath
subsequently applied paint."

https://www.duluxprotectivecoatings....converters.pdf

[Aretino]

OSPHO is my go to rust treatment.

[oldspert]

this ^^ OSPHO converts the rust to iron phosphate. Be careful to wipe the residue before it dries or it will leave white streaks of dried product that will have to be sanded off.

[J Franklin]

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I thought Rustoleum Rust Reformer was a primer. Am I wrong? I use OSPHO with good results. POR 15 is a good choice on clean rusty metal if out of the sunlight, or else it should be topcoated with paint.

[Oldbluoval]

EvapoRust…but expensive
Rust911

Agreed ospho is superb for light surface rust

[gdmn852]

Hello, I used metal prep after wire brush all loose rust until metal is bare from any paint, giving it a few coats of metal prep, rinse and use heat gun to dry , the use the por 15 . On disadvantage of POR 15 color top coat,I usually use the POR top coat in chassis black.

[jrelliott]

Eastwood makes a good primer after cleaning the metal with a wire brush. Cannot remember the name.

[Bob Bidonde]

Abrade off all of the rust you can, and put at least 2 brush coats of POR 15 Chassis Black on all of the metal surfaces. POR 15 Chassis Black needs an overcoat paint because the POR 15 will fade to dull black from the ultraviolet light in sunlight.

[rotorwrench]

The key thing is to either remove all corrosion down to bare metal or use a phosphoric conversion coating to convert iron oxide to iron phosphate. Ospho or some other form of phosphoric conversion coating can be utilized. Ospho is almost a primer in the way they mix in a resin but that resin can complicate things. I dilute it with water if I use it for conversion and then rinse it off. After rinsing it I wipe it down to get the resin off. It's easier to just use a conversion coating that is made to do that.

Etching primers have some phosphoric acid in diluted form mixed in. POR 15 may be that way so that it will treat the corrosion that is being coated over. I've never experimented with the stuff to see how well it holds up. I know what I use works, so I just haven't gone that way yet. Good cleaning and conversion followed by a good primer will work. Follow that with a single stage polyurethane black. I'm currently using paint from TCP Global Restoration products and so far so good.

[Brokenvette]

You can get the stuff at Home Depot or Lowes. One product is Prep and Etch. Works good then use a self etching epoxy primer. Did that on one I did 15 yrs. ago no blisters. Restoring a truck now. Using same process on all metal rusted or not.