doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Coloring of parts (Nitre Bluing)

Would anyone want to share their process of nitre bluing external parts, like trigger guarda, screws, for end metal.
I'm guessing nitre bluing is the correct term.
I have a few parts guns that I would like to experiment on and would like to know the process and steps.
Thanks in advance.

Nitre Blue salts are readily available at most smith sources. The salts are boiled straight without the addition of any water in a steel tank to over 600 F, I use 625 F. Small steel tanks are available from Brownells for this purpose.

The cleaned and prepared parts, same cleaning as rust blue to 600 W/D, then they are acetoned, dried then dipped into the tank and shortly you have your nitre blue finish.....the lower you drop the temperature the lighter the color. I leave the parts in the tank usually about 10 minutes.

I hang the parts using a small roll of medical stainless steel wire that I have, surgical wire. Very small diameter and it will twist over almost any thread size or opening in the parts/screws etc.

Regards,

If you are looking to duplicate charcoal bluing colors then you will need to heat your salts more than 625F. If you are trying to get some form of temper color like fire blue then 625F will work just fine. To get charcoal blue color (blue-black) I have found that 730-750F works for most steels. On some modern steel parts I have had to increase the temp. It takes about 15 minutes to get the correct color. The parts need to be recently polished, degreased,and dried. When the parts first go in I gently agitate them until all of the bubbles are off the parts. When the desired color is reached I take the parts out, let them cool, rinse in water, and soak in oil. On some steels (like 2nd generation SAA cylinders) the parts need to be submerged several times.

I first learned to nitre blue from Oscar. He heated his salts to over 900F. I used to do this but found that the same charcoal blue color developes on most steels at a lower temperature. I have mixed my own salts from salt peter and used Brownells. Both salts give the same results. Oscar was concerned that Brownells salts could not be heated to the correct temperature without breaking down. I have heated Brownells salts to 900F with no problems.

Some steels are more difficult to blue. With a little practice you can duplicate the charcoal blue color found on pre-war II guns. I have blue about 15 Colt, 6 Winchester actions, 3 Marlin actions, and over 25 shotgun trigger guards using this method. I have compared the blue color obtained this way with original Colts in high condition. The colors are identical. I hope this helps.

I don't think David is going to be doing any Single Action Army Colt 'hard steel' Cylinders or Antique Winchester Frames, therefore 625-650 should be a good temperature for his trials on LC Smith parts. Softer steel LC Smith trigger guards and forend irons look real nice at these temps, as they were not 'bright charcoal blue' colored originally. The temperature is an easy variable that he can play with.

I recommend the Brownells Nitre Blue material.

Best,

I would try it but am afraid one sweat droplet would cause a major eruption! lIKE THE COLOR, THOUGH! Steve

Doug,
I'm glad that 625-650 works for you. I must be doing something different because at that temperature range I don' t get the correct blue-black color. I do get a very attractive dark blue at those temperatures. This dark blue looks very nice but doesn't exactly match the original blue- black color of my original vintage shotgun trigger guards. The color difference is less noticeable on guards polished at 400 grit or less. With my setup it takes at least 730F. This is just my experience. Thanks for sharing how you do it.

Shawn,

Thank you for your information and input.....Yes, every set up is a little different and the results vary accordingly.

Your CCH temps on the other post are identical to mine BTW. I am sure your results are really nice. Post some CCH pictures if you get a chance, thanks.

Best Regards,

First thing, thanks to those that answered. Doug is right, I will be trying only L.C. Smith parts. I did look up Brownells Nitre Blue and will get some soon.

I would like to do some trigger guards, and a few non-ejector for-ends. I have a few hammer guns that were "klunkers" and have been working to "fix" them up some and these would be good candidates.

Doug do you do any case hardening/coloring. I also have a few receivers and lock plates that could be done?

Hi David:

Yes, I do a fair amount of CCH, but I am not taking on any more outside business at this time, but thank you for asking David.

Best Regards,

Potassium nitrate is nothing more than "stump remover" sold in 1 pound containers at the local home center ( Lowes, HomeDepot).
It's all I've ever used, gives a nice deep blue/black.

Niter Blue

Scroll down to the 5th post.
More Niter blue

HTH, Robert