View Full Version : Removing bluing

Mike Irwin
August 16, 2009, 03:45 PM
I need to remove the bluing from an old S&W revolver. A lot of it is gone, but I'd like to finish the job and reblue it.

What products are there on the market for this?

I know I can use Birchwood Casey Blue & Rust remover, but it's hard to find, harsh as all get out, and expensive.

Bill DeShivs
August 16, 2009, 04:17 PM
Muriatic acid, for 10-30 seconds.

Mike Irwin
August 16, 2009, 05:24 PM
Where the hell do I get muriatic acid?

How do I apply it?

What strength?

August 16, 2009, 05:41 PM
At the hardware store, it's brick cleaner or toilet bowl cleaner. Ask them where the smallest package is, you don't want the gallon size I guess.

And it's hydrochloric acid - about 30% I think - so use it outside, rinse really well, oil the gun immediately.

I've read of folks using it indoors to clean tile floors and having the vapor discolor every stainless steel appliance in the room.

Have you tried a lead away cloth or maybe blood. I hear that works. :)


edited to add: The directions for cleaning brick is to water it down something like 10- or 20 to 1, but read the instructions. If I was going to use it I think I'd mix a weak solution in a plastic bucket, dunk the gun and then either dunk it in a bucket of clean water or hose it off two or three times. Repeat as necessary. And then dunk it in oil.

Bill DeShivs
August 16, 2009, 05:57 PM
I believe it's also sold in pool supplies.
Use it full strength. Pour it into a plastic container and drop the parts into it. Neutralize it in water with ammonia or baking soda added. Use rubber gloves and eye protection. Regular surgical gloves will not be affected by the acid, and they let you handle the parts. Don't breathe the fumes.
Only leave the gun in long enough to remove the bluing! Check it often.
After rinse, flood parts with WD 40.
When finished, use a plastic funnel and pour it back in the original container for later use.

Walt Sherrill
August 16, 2009, 06:45 PM
I've used the Birchwood-Casey Rust and Bluing Remover (a fluid) and found it did the job well. (It's the only Birchwood-Casey product I can recommend.) You've find it at gunshops and places that sell cold bluing, cleaning supplies for guns, etc. I saw some in a gun shop, recently.

The last time I bought a bottle, it was like $5, but that was sevearl years ago. It doesn't take much.

August 16, 2009, 07:47 PM

Try the folks at Brownell's.com (http://www.brownells.com)- you're looking for their Steel White (http://www.brownells.com/.aspx/sid=3903/sku/1_Quart) rust remover #082-055-032 in a quart bottle. Dilute it according to directions (about 5:1 with pure water) and immerse the gun. You'll need to wear gloves and eye protection is recommended. This product works well for removing old bluing.

After dunking, you'll need a good degreasing/cleaning product to remove all traces of the chemical. They recommend Dicro-Clean 909 (http://www.brownells.com/.aspx/pid=1065/Product/DICRO_CLEAN_NO__909)(#082-005-008), but for a single gun a can or two of brake cleaner will likely do the job.

I'd recommend against muriatic acid or as it is correctly called hydrochloric acid. This acid can attack metal if left too long. And you need to know the strength of the acid so you can properly dilute it, something that's often missing on the acid sold for swimming pool use (generally a 10%-12% solution). Concentrated acid will fume if it is above about 32% and breathing equipment is needed.

James K
August 16, 2009, 08:43 PM
That Rust and Blue Remover IS muriatic acid. It does a good job, but do several appllications rather than leaving it on too long as it will frost the steel.

Incidentally, for those who think factories apply a "mirror finish" polish, using blue remover is an education in how much roughness hot salt bluing can cover up. And why gunsmiths who try for a "mirror finish" are never able to duplicate the factory finish.


Mike Irwin
August 17, 2009, 12:19 AM
Excellent information. Thanks, all.

The gun I want to reblue is an M&P in .32-20. The finish is probably only about 50%, it's got a fair amount of pitting, and a bunch of nicks and scars.

The bigger problem, one that I've yet to solve, is that it's almost impossible to thumb cock for single action. It locks up. But pulling the trigger for double action works, although it is rough and hitchy.

I think the cylinder bolt is the culprit, but I've not had a chance to thoroughly investigate it yet.

August 17, 2009, 06:38 AM

Use a jeweler's loupe and inspect the star extractor palls where the hand engages. Look for a small gouge in the surface or some rough spot or burr. Also check the nose of the hand to make sure it's not burred.

I'd double check the pin(s) in the hand to make sure they're not worn loose, as well as the hammer and trigger studs.

I'm betting on a worn or pitted extractor pall. Especially if some chambers work smoother than others.

Mike Irwin
August 17, 2009, 10:16 AM
The pawls are fine.

The hand is fine.

It still does it even with the hand removed.

The studs are all straight.

The problem seems to be the interaction between the trigger nose and the cylinder bolt.

August 17, 2009, 11:43 AM
Evapo - rust

works very well and will coat the part after you remove it so it won't rust for a day or so. Tried Brownell's new rust remover but it doesn't work as well.

George R
August 17, 2009, 03:33 PM
I agree with JGlenn. Evap-O-Rust is the best. I buy it by the 5 gal bucket, but you can get small quantities at an auto parts store. You can leave the gun in it for a prolonged period of time and not have to worry. Muriatic (swimming pool) acid can pit the hell out of your gun in seconds.

Mike Irwin
August 17, 2009, 05:46 PM
So Evap-O-Rust will remove bluing and prepare the surface for new bluing?

August 17, 2009, 07:44 PM
Evaporust is a chelating compound and works very well. So does a competing product called Rust Release. I have tried both and the latter has a slightly lower pH and works faster. Neither is something you want to leave steel in too long. Figure 15 minutes or so. I've used these on red rust, and if you have any, it will get rid of it. It will, however, leave the surface slightly matte after longer exposure I think all the finish removers will if you leave things in them long enough. It's not a bad surface if you are going to rust blue it later. If you leave something in either brand long enough a black surface coating appears that has to be rubbed off. But I agree it is good for attacking any kind of iron oxide, the magnetite that constitutes bluing, included.

Another product that is quite good is Iosso Quick Strip (http://www.iosso.com/MivaStore/merchant.mvc?Screen=PROD&Store_Code=A&Product_Code=00018&Category_Code=GunCleaning). It will take off bluing or Parkerizing and is pretty easy on the steel. It is designed specifically for this job. I've used it to strip Garand parts for blasting and re-Parkerizing.

I also agree with avoiding the hydrochloric acid variants. They work, but they activate the surface so there is a tendency for surface after-rust to appear, unbidden. That activation and surface etching can be uneven. The other products above are just a better, more modern chemistry for the job. If you get after-rust from any removal compound and intend to rust blue anyway, just boil the rusted part in distilled water as soon as the rust appears to convert the red rust to black magnetite. If you are going this route (and it is a good one for home restoration where getting into molten caustic salts for hot bluing is undesirable, though pitting is tough to handle with it), be sure you've read up on rust bluing and have all the steel wool degreased or the fine brush ready that you intend to use for carding. That way accidental rust can be taken advantage of promptly.

Steel white also removes rust with less adverse impact than hydrochloric acid. It goes the other route, being mostly potassium hydroxide, IIRC. Strongly alkaline. Like lye, it is a strong degreaser as well, so you should not need a degreasing compound after using it. Just a cold water rinse that lasts long enough.

Mike Irwin
August 21, 2009, 06:40 AM
Damn... I figured out the problem with the action locking up...

It appears that someone decided to "adjust" the timing by thinning the hammer nose where it engages the cylinder bolt.

All their efforts did was destroy the timing. The cylinder bolt isn't being withdrawn quickly enough, so the bolt still has the cylinder locked when the hand is trying to rotate the cylinder.

Then the thin trigger nose is also release the cylinder bolt WAY early.

I think the only solution to this one is going to be a new trigger, and I really don't feel like fitting a new trigger.

August 21, 2009, 10:03 PM

Unless the cylinder stop is heavily worn, my experience is that a new case-hardened trigger will need minimal fitting.

You're using the term "Hammer Nose" when I think you mean the "finger" on the front end of the trigger where it engages the cylinder stop. (S&W calls the hammer-mounted firing pin a "hammer nose").

A new trigger and new cylinder stop may need fitting to prevent premature retraction of the stop.


Mike Irwin
August 22, 2009, 06:42 PM
Yeah, I was talking about the wrong parts.

See what happens when you post before your first cup of coffee?

August 25, 2009, 06:20 AM
viniger will remove bluing