View Full Version : cold rust bluing

July 2, 2001, 12:24 AM
Can anyone tell me how this is done? I have a decent shop and hope to ry it at home.


George Stringer
July 2, 2001, 07:25 AM
Mike, basically you just follow the directions on the product you choose to use. You can prep the metal to the desired finish by bead blasting for a matte finish, use paper starting with 220 grit and increasing to 400 grit for a "factory" finish. Use acetone or Brownells TCE to degrease. Oxpho-blue also from Brownells is a very good product for a complete rebluing job. www.brownells.com George

July 2, 2001, 04:04 PM
Suggest trying Brownell's at:
I think they offer FREE instructions about some bluing systems.

I assume you're talking about real rust bluing vs the bottled cold blues sold at Wal-mart.

Real rust blue is applied by heating the part in a tank of boiling water, swabing the chemical on, allowing it to work, "carding" it off with fine steel wool, and repeating the process many times to get the depth of finish desired. This is easy to do, but very time consuming, and does give a fantastice true blue finish.
Since it is labor and time expensive, few 'smiths offer it.

The standard "cold" blue is really a touch-up for scratches and small scuffs. It won't do a really good job of matching an original blue job, doesn't do a very good total refinish, and is NOT durable.

To do this type of finish, clean the parts with a GOOD solvent (acetone, laquer thinner, etc). Warm the part up (warm NOT HOT), apply the chemical with a Q-Tip or swab, and allow to work according to the directions on the bottle. Wash off in warm water. Lightly rub the part with very fine steel wool, clean with solvent, and re-apply until it looks OK. After the final rinse, coat with a good common oil, and allow to "age" for a day or so.

July 2, 2001, 10:35 PM
I've been using the Plinktons Rust Blue and I' hooked on the finish. It takes weeks to do a rifle so it's not really useful for production. I bought a bottle of it when it was 6 bucks at Brownells now it's $18! I've done 4 rifles and lots of various parts- I've still got half a bottle.

I've found the acid solution will etch away either a fine sandblast or polish finish so a good 400 or 600 grit sandpaper finish or 3M Maroon pad will do. The gun must be absolutely free of oil. A boil in DicroClean then a degrease is in order just to be sure. From this point on anything touching the gun must be oil free so wear new cheap garden or work gloves when handling the steel.

I use QTips with some of the cotton pulled off. The Qtip should not be dripping with solution-- three dips usually covers the rifle.
First time coat twice, the steel will frost grey in a few hours--provided you are working in a humid environment...

I boil distilled water on my gas grill outside. Make sure no oil drops are swirling on the surface of your water. A rolling boil will provide the best results. The gun will turn black. Use the Brownells .0025 Stainless Brush Wheel to card off-- other harsh wheels won't allow a build up of blue rust.

Soft steel takes one to three cycles. A Springfield barrelled action took about ten. Remington 581 about 7 or 8 cycles. Trigger guard/magbox about 4. Hammer heads about 5. Softer steels should be monitored closer as the solution could pit the surface... Hard steels can go a little longer up to 3 days for a good fine red rust. After a while, the solution won't penetrate the blue and you're done.

Polish/Blend with a 3M pad and WD40. Keep applying the WD over the next few days as the rust may want to continue... I then apply a coat of wax.

Nothing can touch this type of blue-- it's almost as tough as parkerizing but much better looking.

July 3, 2001, 05:05 PM
You can't use just nitric acid? That's what's listed in an old gunsmith manual I have.

What do you recommend for plugging the muzzle and breech?

July 3, 2001, 11:43 PM
I'd buy a product made for this specfic purpose,....better results.
I believe Brownell's sell the threaded rod and rubber plugs for the bore. DON'T try to shove or hammer a plug into the bore. these will blow out in the boiling water bath, sooner or later. Not only can this screw up the job, you can get hurt.

July 4, 2001, 08:37 AM