doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Speaking of Rust Bluing....

Mike-- sorry I'm a little slow on the uptake here, but would you clarify what you are so describing? Are you saying that you look for water or steam leaks along the ribs and then re-solder any spots that aren't water tight? And then would you try to seal up the weep hole and front bead hole before rust Bluing?

Ernie-- Do you worry about how much wd-40 (or equivalent) would remain between the barrels after the soak?

Thanks all for the input. As with many things, it seems there were multiple ways to skin the proverbial cat.

Here's a follow-up / add on question: when polishing the barrels in preparation, what do you all do about the 'hard to reach" areas, like the nooks and crannies along the lumps, ribs, etc? It seems inevitable that some areas will remain less polished or even untouched.

The only things that gets blued that I do not polish is rib mating, I use a fine wire wheel for that. Everything else gets polished in line with the bore using backers of various types, I usually stop at 400 grit, I will go higher if I want a high luster blue.

These are great: https://www.amazon.com/Polishing-Woodworkers-Automotive-Sandpaper-Woodworking/dp/B086YXR9RH?th=1

Also hobby polishing sticks from Steve's Hobby(I'm in no way affiliated )


Tongue depressors with abrasive paper stuck to them are handy as well.

As a final step to my polish I run the barrels over a carding wheel(I card by hand) and the wheel homogenizes the finish nicely removing any trace your polish paper has left behind. When Nitre bluing I use a similar process but buff on a felt wheel with fine compound right before heating the part you are going to color.

Thanks Steve. That makes sense, and those contoured sanding blocks look like they will be a great help.

(you also answered another question I had-- many things I've read say stop at 320 grit, but I have had the impression that a finer grit polish would (take more time and) produce finer results, assuming you like a relatively high luster).

Yes, but high luster rust blue is very tricky and requires more than a higher degree of polish. You cannot let the acid work on the metal too aggressively. Environment is very important. I find a rust box too intense if I want a high luster blue. Strength of the solution, humidity, temp, and time all come into play and there is very little margin for error. More input from our British friends would be greatly welcome. I had it worked out nicely with Pilkinton's in my last shop and my current one, it is no longer produced and I am working towards similar results with a batch of Brownell's that I have. I really need to make my own, I do making my own browning solutions.

Woodreaux,
As noted above, I believe damascus and I use different processes to blue the barrels. I use the slow rust or cold rust process with a German solution. I clean the polished barrels with acetone and after cleaning am careful to avoid touching the barrels with my skin. I apply the solution with fine steel wool (also cleaned with acetone) dipped into a small amount in the cap of the bottle. After evenly covering the barrel, pour any leftover solution out of the cap, but not back into the bottle. Then put the barrels aside to rust. The amount of time for rust to form depends on the temperature, humidity, type steel, and degree of polishing. Since you can't time it, just watch it. The first application will take a while and will be pretty light in color. After a layer of rust forms boil it in plain water to kill the rust, and card the rust off with steel wool cleaned with acetone. I learned to card the rust with a wire wheel in Germany, but I wasn't able to find one here that was fine enough to card without damaging the surface, consequently the steel wool substitute. Boil the barrels long enough to heat the steel so it will dry when removed from the tank and gently shaken. The rust will stop quickly but I usually let the barrels cook 15 minutes. If I don't have time for another cycle, I don't card them until the next day. Never let the barrels rust overnight. They will be ok overnight if boiled but will pit overnight if not boiled. I leave the bead in and if there is a weep hole, I leave it plugged. If water leaks, it will be obvious without looking closely. Rust boil and card as many cycles as necessary until you are satisfied. I polish with worn out 320 grit cloth after 180 and 220 backed with files (mostly Barret or Pilar files or old files ground to fit into close places). The solution I use will work on small areas that couldn't be polished and the color will still be even, and partial areas can be rusted and carded to even out missed areas. When you are satisfied, oil the barrels with regular oil and clean the bores. To finish, polish the barrel flats and side of the locking lugs, the extractor and rear barrel face, as well as the end of the muzzle bright, with worn 320 grit cloth.
I learned to use cleaned steel wool to apply the solution because it may remove any contaminates in the air (oil droplets) that find their way to the surface. This process leaves microscopic pits in the surface and color inside the pits, so it takes extreme wear to remove the color, also extremely fine polishing is not necessary and depending on the hardness of the steel the solution may not "bite" and the part may have to be re-polished with a coarser grit. I don't have experience with the process damascus uses, so I can't answer to it.
Mike

I have done many, many rib repairs. I do not seem to have near the problems you have Karen. Less gobs of solder, more time prepping and the proper heat envelope and the vast majority of time a rib repair can be performed cleanly and successfully.

As always, what a pleasure for you to share the depth of your experience with us.

All my best,
Steve

Der Ami. Rust bluing is exactly what it says. Slow rust bluing is only slow because it takes time for the rust to form. There are rust blue formulas that will rust the metal in seconds or minutes, these mixtures where instant or rapid rust bluing solutions. You do not see these rusting solutions today because of there high toxicity and high cost due to difficulty in obtaining all the constituents. This method of rust bluing had major advantages as far as the gun trade was concerned having extremely fast turnaround and the mixtures could be used to instantly touch up worn blue sections in barrels. I do still have a pint of this rapid solution for my own personal use. I do think that if people are interested in the art of bluing and browning the best investment people can make is purchase a copy of "Firearm Bluing and
Browning " by R,H. Angier an old book but thankfully always being re printed.

damascus,
I understand, but I use the slow process because that is what I learned and cannot address the other processes (Belgian or others). I don't call myself a gunsmith and don't do outside work so turnaround time doesn't mean much to me, anyway I don't stand around waiting for the rusting, I can do something else while waiting. Also, in my opinion (I know what opinions are like) slow rust results in a better finish, if you have a different opinion, I respect it.
Mike

I use both Slow Rust (Cold Rust) bluing and Express Rust (Quick Rust) bluing.
I used to use the Belgian Blue formula (Quick/Express Rust) and some others in that same catagory. They worked great. Mostly due to the mercury compound(s) in them (merc bi-chloride(?).
The old formula Birchwood Casey muzzle loader Bbl Brown was another that worked very well. Also contained Merc BiChloride.
(Their improved formula does not)

After many years of feeling bullet proof from such things as merc poisoning/damage to the nerves, old age finaly rings a bell and tells you maybe there's a different way to go,,just to be safe.
Yes we all played with liquid merc in school 'plating' copper pennys and such and none of us died from it AFAIK.
But the constant exposure and more so the thought of the merc in the carded dust,,on the tools, the floor, all over the shop and myself and clothes told me it's likely not a very good plan for the future. Even if I don't care about just me, how about others around me.

So I went with Mark Lee's Express Blue maybe 25+ yrs ago and am entirely satisfied with that for the Express Rust process.
I admit that I rarely use the Express Rust Blue anymore except on some touch up and hurry up jobs. But it certainly has it's place. Lots of kitchen stove top small jobs, it's great for that.
No merc in it so I am fine with the stuff.

Brownells brought back the old Herter's Belgian Blue a some yrs back and said it was the same orig formula. That old stuff had the mercury bi-chloride in it.
I wondered if the new Browneels formula maybe substituted something for the Mercury.
I bought a small bottle of it and tried the test for merc (swab some on warmed Brass, see if the mercury 'plates' out onto the surface).
It did,,I was surprised. I would have thought that selling a mercury compound soln would be off the table at this point in PC/Greeny time.

For Slow Rust Blue I use Laurel Mtn Forge rust soln. It has bit of nitric acid in it as well as copper sulfate.
I've used a lot of other solns as well,,this one works well and I've stuck with it overcoming it's tendency to after-rust and to
'plate-out' the copper at times when applying.
I used to use Sal-Ammoniac water soln way back. Some chips of the soft solder flux disolved in pain water
Most anything that will cause a fine rust will work.

I try not to let the Slow Rusting cycle build up very much,,just a very faint brown/red color on the surface. No heavy rust coating
I lightly drag my finger tips down the side of the bbls, if I can feel a very slight roughness,,they are ready for the boiling water tank.
You will get a fine layer of color with just a faint rust coating.
No need for the rust coating that looks like an old piece of farm equip left out in a field for a few years.
That just pits the metal and muddys up the water tank.