How to restore rusty, blued steel

[Ian]

This comes up a lot here. Guns, reloading tools, bullet moulds, hand tools, etc. A part that was polished and blued has rusted and we want to remove the crust, stop the rusting process, and restore the appearance without removing all of the original bluing.

While we can't put metal back where it has been etched away, we CAN stop the rust and preserve the finish. Here's how:

Degrease the parts and boil them in plain water for 30 minutes to an hour to convert FeO² to FeO³. Card off the bright red rust with a fine-bristled stainless steel carding brush or degreased steel wool. Soak in kerosene or Varsol overnight, dry, and oil the part.

Here are an unblued and very lightly rusted cold chisel, a blued and very rusty punch, an unblued and very rusty home-made tee wrench, and a polished, blued Quadrajet socket with a couole spots of bad crust. The large and small carding brushes are from Brownells.

 

[Ian]

Here they are boiling away:

 

[Brad]

Doesn’t your wife have a pan just like that?

 

[Ian]

She DID.....

I already got a blast of chit from her when I headed to the kitchen with my stainless pot. It's cold in the shop.

Waiting on them to convert.....

 

[Joshua]

I sneak my cap n’ ball into the oven. But that is the extent of my kitchen use.
I do stuff like this on the Coleman stove outside.

 

[Ian]

After boiling:

 

[Gary]

AND the rest of the story!!

 

[Ian]

After carding off all the loose stuff:

 

[Ian]

Now, to take it further, I blued the punch and chisel with four cycles of Mark Lee express blue by simply boiling them to get them hot, letting the water flash off, and wiping on the solution with a folded paper towel. After rusting for a few minutes, the parts were boiled again for 2-3 minutes and carded, then reheated, solution reapplied, allowed to rust, and repeat.

Then everything was dunked in Varsol for a bit, dried, and lightly oiled. The bluing is still soft but will harden over a few days.



The lettered sides of the punches were originally in the white for contrast, now it's all blued over (the original bluing, the rusty spots, and the previously unblued places). The result is an even blue-black color all over. I didn't reblue the tee-handle or the socket.

 

[Ian]

The main advantages to converting the rust by boiling and carding is any original bluing is preserved and the surface of the metal is unharmed (especially lettering) while all rust, even down in holes and crevasses, is passivated. This makes the process ideal for guns, though it obviously won't remove pitting. Going over the gun with Oxpho cold blue or hot-water bluing will even out the color if appearance is what you're after.

 

[Gary]

Excellent!!

 

[Missionary]

Well explained ! Boiling is the way to go.

 

[Spindrift]

Excellent tutorial, thanks!
Now, I learned something new.

 

[Ian]

Thanks, gentlemen. This is an ancient method but few seem to know about it. Maybe a little better picture: