Ospho question (on guns)

twobit

New member
I regularly use Ospho on bare or rusted metal before I prime and paint when working on trailers or other welding projects around the ranch. Ospho is that watery green liquid available at hardware and paint supply stores that you brush on bare metal. It is a rust converter, changing the metal to a black color.

Has anyone ever tried it on a blued firearm that has a few rust speckles on it? I thought about buffing with fine steel wool, applying Ospho, then lightly buffing again with steel wool before oiling the metal. Just wondering what it would do to the blueing? Trying to figure out a way to treat the rust freckles without damaging the rest of the blueing. Thought I'd ask before I try and find a spot on a old gun to experiment on.
 
Well I'm hearing that Ospho will probably damage the blueing, which I thought it would. Most common suggestion I've gotten is 0000 steel wool wet down with Rem oil and be careful not to rub too hard.
 
I've used a gallon or three of Ospho over the years and I'm not using it on any of my guns. I first used it on rusty holes in my 1978 Datsun B210. I've used it on old fuel oil tanks prior to painting, rusty mail box posts and other scaling, pitted pieces.

It's phosphoric acid and it's thinner than water - you can't control where it spreads. "a balanced formula of Phosphoric, Dichromate, Wetting Agents and Extenders "

I have part of a gallon left after recently scraping, treating and painting the iron railings on the front of my house. (After 100 years they needed resetting where they'd rusted off at the concrete steps and porch. The guy welded new heavy gauge legs on the railings and core drilled the old holes to reset them. Built me a gate, too. :) ) But I did the scraping, sanding, wire brushing, Ospho, primer and 2 top coats. The repair guy was right - spray paint. I asked about sandblasting it all while he had it down and at his shop, but he wasn't in favor of it.

Joh
 
I have tried a lot of cold bluing products for everything from spot bluing to complete barrel bluing. Discovered Brownell's Oxpho Blue last year and it is by far the best cold blue available. As I understand, it is nearly the same basic chemistry as Ospho but designed for bluing.

0000 steel wool polish and several applications of Oxpho Blue result in a very acceptable and durable blue finish.
 
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