Nitre Bluing a Revolver?

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deerslayer303

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I'm wanting to Nitre blue a highly worn S&W Model 10. Will the high temperature of the salts affect the hardening of the cylinder and barrel on a revolver? I think the salts melt at 600 degrees. The parts will soak for 30 minutes maybe longer depending on the time taken to achieve a color I want.
 
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You have a tank big enough for that?

I'm not an expert on how modern gun steels are hardened/tempered.

Although I would not advise it, I have to admit it sound like an interesting project.

If you do attempt it, please post pictures of the results
 
Oh yeah, I have a stainless steel trough that would work nicely on my outdoor propane burner that I use for processing lead. From my reading I've found some say it won't harm the strength of parts that are susceptible to pressure amd some say it will.

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You can't Nitre blue a revolver; it will ruin it, unless you do not intend on ever firing it again. Any tempering in the frame, cylinder, or barrel, will be taken to spring hardness or less, (570° F. - 650° F.), and that is not hard enough, especially for a thin walled cylinder under high pressure, even in a .38 special smokeless cartridge. Factory parts such as frames, cylinders, and barrels will have a hardness to them similar to gears, (not as soft as springs, but not brittle; around 440° F. - 500° F.), which means a tempering temperature that produces a brown color, and is lower than it it is for springs. Also, any close machine fits could/will warp, and possibly even the barrel's bore along its length, which is why we only Nitre (heat) blue things such as screws, or a part that will not have any force applied to it from firing.

The closest thing that you will get to that color of blue, (having a bluish tinge), would probably be a hot water Belgian blue, or a paint. The standard factory finish, for a S&W revolver, is a high polished black oxide from one of the types of hot bluing. That temperature is no higher than 280° F., which is well below the tempering range, and not enough to cause it to warp.
 
Thank you Dixie! Well I guess that's out. Though, I have found a few guys around here that still Hot Blue So I'll go that route. I just don't have the heart to leave it in its current condition.
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I don't do bluing any more, now that I've retired, but Guncrank at CW Shooters Supply does that type of finish. You might give him a PM, if you don't care to ship one off to Louisville. He does a high-polish finish that can bring that back. There are a few pistolsmiths on here. If you are capable of doing the polishing, then you might save a few bucks.

That looks like it might be an ex-police service pistol, (I noticed the 12 stamped on it), and they do clean up good. That number is probably removable, if polished correctly. It can be taken out and blended in, especially if it is not stamped too deep.

I personally like the model 10, and think they make a decent home defense weapon.
 
The finish on that gun is far from needing to be redone! My recommendation is to leave it alone and enjoy the gun.
If you feel you must refinish it, my suggestion is to have an upgraded finish applied. Hard chrome, Ionbond, or even nickel plating are much better finishes than any bluing or any of the gun paints. The upgraded finish costs about the same as professional rebluing, and should last a lifetime.
 
Somehow, I have the feeling that there is a misunderstanding here, possibly confusing Nitre blue with common hot tank blue (hot salts blue), which will certainly not harm that revolver. Hot tank blue uses salts dissolved in boiling water and temperature usually runs well under 300 degrees F, quite safe for heat treated material. Few small shops do hot tank blue any more as OSHA considers it hazardous*, but there are larger places who have the proper safeguards and do tank bluing all the time.

Nitre blue uses bluing salts that have been melted by heat (not a solution in water); the molten salts run up to 650 degrees F, which is enough to ruin most heat treatment.

*Small shops have often replaced tank bluing with the use of what is essentially paint, which gives good results but is nowhere near the quality of a good hot tank bluing job.

Jim
 
If you want to have the whole gun reblued, you can have small parts with nitre blued for a touch of accent. You could have the whole gun done in a high polish black oxide salt blue and then have the trigger/cylinder latch thumb piece polished and nitre blued.
 
Yes, that revolver has already been reblued, and whoever did the polishing wasn't that great it, as they rounded over the sharp corners. That can be somewhat corrected, though the crane will take some work on it, (especially its fit to the front of the lower frame at the hinge joint), and I'm not sure that the flutes on the cylinder can be brought back to the original sharp look.

My guess is, that it was an ex-police revolver, and its finish had been pretty worn, so they reblued it. It now shows the telltale signs of holster wear on the barrel, so it has either been used for a while since its last refinishing, or it has had the barrel replaced. It seems to have a slight mismatch in the color of the frame to the barrel, which can either be from the bluing process not being performed correctly, or it may have a new barrel on it. That is, it looks to be a slightly mismatched color to me, though I may be incorrect.
 
JamesK, thanks for the explanation of the bluing methods. I was wondering the difference in the two but your post cleared it up. And thanks Bill and Dixie I didn't even realize it had been reblued once already you guys have a very sharp eye. That pic is after I cleaned it up with some elbow grease, lots of gun oil, and a good bit of OOOO steel wool. It was a hot mess when I got it from J&G sales. Below is a pic of how it came to me. The thing shoots VERY good, one trip to the range had me hooked. I bought this revolver because my father in law has a 10-8 that he let me run a box of rounds through. And after that 50th trigger pull it left me wanting one.
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My own feeling on that gun (after I saw the last pictures) is that it is beyond repair from either a cosmetic or a practical viewpoint. Trying to remove the deep pitting from the sideplate will make it too thin and weaken the frame. I would just carry/use it that way, and small loss if anything happens to it.

Maybe Cerrakote or some other paint type finish could be applied, but honestly I wouldn't bother. Take it down, clean it well, oil it up, and tuck it in a holster.

(I know that goes against the grain for most of us, but a gun is, after all, a piece of machinery and not many folks worry if that old "Cat" grading the road has rust on the treads. It works just as well.)

Jim
 
Thanks for the recommendation Dixie
I still do hot bluing but certainly not a big shop as it is just myself.

As to nitire blue , there is a pistol smith that posts on Facebook that he does heat blue on revolvers. The ones I have seen where beautiful.

I would not do it myself as I question his understanding of metallurgy. But it did look fancy.
 
A couple of thoughts. When someone is reported as "doing" great bluing by some secret method other than the standard tank blue or rust blue, I tend to be suspicious. Sometimes, the "secret method" is simply cold blue and BS. I have heard of gunsmiths who claimed great results but used methods that would destroy the heat treatment. One "gunsmith" just polished the gun and turned his torch on it. Heat treatment? What heat treatment? I did not take him up on an offer to test fire a .378 WM he "reblued".

As to TINCANBANDIT's work, it is good, but I wouldn't call it restoration. It does turn a rusted relic into a decent looking gun, with a corresponding increase in value, but a lot of metal and substantial areas of markings have been removed. I am doubtful that it could be done with enough improvement to make the effort worthwhile on a commercial basis.

Jim
 
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