OSPHO and the like- POR 15

[Brian Duff]

So that thread had been Hi-Jacked. Consider it grounded and jump on this one!

Topic is something like what do you use to bust corrosion or inhibit it?

knothead
Junior Member Join Date: Nov 2008
Posts: 6



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Does anyone else use Ospho for soaking rusty stainless?

"Originally Posted by RoyB
What is Ospho? Many substances have different names here in Australia. For example, beer is referred to as 'Piss" :-). Seriously! "


"I hope no one thinks I am trying to promote the stuff. I just wondered if others have used it for soaking rust stained stainless.
The below is from their website."


"When applied to rusted surfaces, it resists/retards rust in chemical change on drying to a tough, hard surface ready for priming. A paint job will last longer after an application of OSPHO because subsequent paint coating securely attaches itself so that moisture and oxygen normally do not attack the metal. OSPHO is water-thin, can cover a larger area than paint, and goes on easily. It is equally effective for exterior and interior work alike. SKYCO OSPHO: a balanced formula of Phosphoric, Dichromate, Wetting Agents and Extenders . . . compounded exclusively by the Skybryte Company since 1947 ... recommended by paint manufacturers."

[Brian Duff]

Is oshpo like POR-15 ? I cant see any coating be beneficial to stainless in the situations we have onboard boats above decks or burried in decks.

[Bob Pingel]

OSPHO converts rust into a different compound - a dark grey harder substance that holds paint well. POR15 and alike encapsulate rust and present a surface to paint. Neither would seem applicable to rigging stainless.

OSPHO does not seem to be much of a penetrant and when it does hit rust it makes it into something harder, which if you are dealing with threads or moving parts would be bad.

I'd use some sort of penetrating oil to soak rusty parts -- LiquidWrench, PDBlaster, or my favorite Kroil.

Bob Pingel

[knothead]

Originally Posted by Brian Duff

Is oshpo like POR-15 ? I cant see any coating be beneficial to stainless in the situations we have onboard boats above decks or burried in decks.

Sorry, I wasn't very clear.
I use the stuff not as a coating, but just as a way to remove the rust from stainless.
I soak the part for a few hours and then rinse it with water, let it dry and lube if it needs it.
It makes the stainless look pretty much brand new without any scrubbing or buffing.
I was just wondering if anyone else used it. I use it on old clevis pins, screw pin and snap shackles. Just about anything that is stainless. It eats aluminum like candy.
It seems that the acid only reacts on the rust not the metal. But I'm not completely sure that it's a good idea.
I have used it on a steel trailer before painting. It does cause the rust to change color. I guess that is the purpose for which it was designed.

[Stumble]

Personally I just don't trust SS once it starts to rust. I know it is more expensive, but once SS parts start to rust I normally just replace them. Particularly pins, shackles and other small bits. Large parts, or things prohibitavely expensive to replace I try to clean and identify why they are rusting then fix the problem.

[Douglas]

You might get more acurate info by reading at the website below .


http://www.outokumpu.com/application..._113142858.pdf


Douglas