doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Winchester Mod 21 Question re: Barrel Bluing

This relates to a nice 20 Ga Model 21 that I restocked a few years back. The stock came out great and I had the receiver blued (hot) and it came out great. I was thinking at that time that I should rust blue the barrels, which I did. They looked pretty good for a while, then not so much. I did them again with the same result. So I did it one more time with a few extra iterations of the rust blue; same story, now the conclusion: Winchester steel needs to be hot blued. I suppose the construction of the Winchester 21 barrels--dovetailing of the barrels and rib--at least the top rib (not sure about the bottom rib) was engineered into the design to enable them to be Hot Blued.
So I think I am finally of the opinion they SHOULD be hot blued. Now--who to send them to? I'm not set up to do it. Thanks, Gil

Winchester 21 barrels are rust blued. Don’t hot blue them unless you want more problems, e.g., the Keel rib and bottom rib might fall off. Send them to someone who knows rust bluing.

I would be interested in hearing what is happening to the previous rust blue jobs you've done. Are they rusting or turning a different color? Is the finish mottled or uneven? Or is the blue simply wearing thin prematurely?

Also, what process and rusting solution did you use? Was it a true slow rust process, or an express blue? Did you boil the tubes before carding, or did you use steam for the conversion step? What did you do to neutralize after bluing, and what did you use for a final curing oil. Knowing these details might shed light on how or why your previous attempts failed.

I agree with Buzz, it appears that all Model 21 barrels were rust blued originally. The barrels were joined with a tin/lead solder, so if all traces of the hot salts were not totally neutralized and flushed out, hot salts bluing could come back to haunt you. Your experience shows that sometimes it is necessary to vary the rust bluing process, because all barrels are not made from the same alloy of steel.

That is why the bluing is different colors in different areas of the gun. They blue different areas of the gun using different methods.

Gil: from Colonel Charles Askins, The Shotgunner’s Book, A Modern Encyclopedia, 1958
https://archive.org/details/Shotgunners_Book_The_A_Modern_Encyclopedia/page/n27/mode/2up
Present (Winchester Proof Steel) alloys shape up like this:
Carbon .45% - .50%
Manganese .60% - .90%
Chromium .80% - 1.10%
Molybdenum .15% - .25%
Phosphorus .04% maximum
Resulphurise to .04% - .09%
(AISI 4147 with slightly low manganese)

The single sample I had tested, of which unfortunately I don't know the DOM
C .34%
Nickel .09%
Cr .62%
Mo .3%
So non-standard (low Cr and high Mo) AISI 4135 medium carbon low alloy with a low concentration of nickel.

I'm no help with how to blue the stuff, but Mike Hunter would certainly know, and I hope he's still at it.
http://www.mikehunterrestorations.com/

Keith et al: The first attempt was using Pilkingtons, slow rust blue--typically 3-4 hours rusting in a humidity box, boil, card and repeat 6 x. Neutralize with baking soda in H20. Looked good when finished. Didn't hold up. Next was using Mark Lee, with added ammonium chloride. Neutralize w/ baking soda. Looked great when finished but didn't hold up. Ditto for the 3rd attempt; that was about a year ago.

I have blued probably 30 other shotguns over the years and all except for the Winchesters have looked great when completed and have held up well. I have found the Mark Lee bluings to hold up every bit as well as the slow, slow rust process.

Drew: Thank you for your input. I don't know how you catalog so much information but thank you for sharing it!

Gil

I had Briley relay the vent rib and reblue the barrels on my 21 Trap and the results were excellent. In fact much better than the results from CSM!

Not sure now but they use to send their bluing out


John
Arrieta2

Heat.

When rust bluing anything Winchester I don't use the slow process.
Below is a quick write up. Not getting into polishing, tools, rust solutions, etc. If you're familiar with the process, this will make sense. (Have a dinner date with my wife.)

Have water boiling, place barrels in boiling water after final prep.
Remove from water, blow crevices dry with compressed air.
Apply rust solution. If barrels are hot enough it should rust/evaporate almost instantly.
Boil barrels and then card.

Repeat as may times as needed. (Move quickly!)
I also keep a propane torch handy to keep things warm/hot but this requires CARE.
When done blacking and carding, coat heavily in non-detergent motor oil for at least 24 hours. Many oils have additives that will loosen rust blacking. As me how I know.

The use of a heat source is VERY common. You can even find YouTube videos from inside Turnbull's shop showing his guys using this method.
That said, stick to the cold rust method if you are not comfortable with the process.

I had some great mentors who gave me hints & tips, but my process is not exactly the same as theirs, so this is just a guideline to be adjusted to your shop, tools and conditions.
More than one way to skin a cat.

In my experience, using the method that UTSG described will work, but…and this is just my opinion….will only result in a low sheen, satin blacking that doesn’t look like original Winchester high sheen blacking. Even Mark Lee recommends blasting the barrels or parts with a fine abrasive before applying solution. It’s hard to get a high sheen black when you have to do that.
In order to both polish the barrels to “chrome” and then subsequently get the slow rust solution to gently bite into the polished steel, you need to develop a method that allows that to happen. That’s a trick I’m not quite ready to part with quite yet.
I have not had good luck getting Mark Lee solution to bite into highly polished steel. It doesn’t work very well for me on anything polished to 320 or higher.

I purchased a solution recipe from a friend in Montana (he’s out of the blacking business) and I’ve seen Winchester model 21’s and model 12’s he’s blacked and they look amazing, correct sheen, etc. This solution has both Mecuric Chloride and nitric acid in it, albeit in very very small quantities. The solution gives a beautiful deep, high sheen black on highly polished steel. It usually takes about 10 to 12 cycles to get the correct color, on high chrome steel and nickel steel, a few more cycles to get there. He got the solution recipe and method from a long gone Montana gunsmith who also restored Winchesters. I personally have not used the solution yet on a set of barrels, only on test coupons of steel.

I’m thinking you’re stopping a little too early on your cycles. Have you tried going 10 to 15 cycles and seeing if the black holds longer? Also, maybe try letting the barrels cure in oil (like utsg said, non detergent type, I use non detergent 30wt compressor oil) a bit longer than 24 hours. I sometimes let the oiled barrels sit for a few days. Get a clean paper towel to wipe the barrels down and if you see dark stuff on it, let them sit longer.
Ensure you’re also using a saturated solution of baking soda and water to neutralize and let them sit in that for at least an hour or two. That was a great and very helpful tip from an old time barrel blacker that I got a while back. It makes a difference.