Case hardening-chemicals?

[MIEagle]

I have a Browning 1885 BPCR. Awhile back, before I joined this website, I noticed a drip-like gray colored mark on the left side of my receiver. I only use bore cleaning solvents appropriate for black powder and have used Simple Green and automotive antifreeze for swabbing the bore between shots. One time I did use Shooter's Choice Lead Remover in the bore. Could that have caused the mark on my receiver? Thank you.

[bedbugbilly]

Is it simulated case hardening or actual case hardening? Or is it blued? Probably something that you used had a chemical in it that could damage the finish. As far as blueing goes . . . there are a number of things that can affect that finish. For BP cleaning, I use a mixture or alcohol, murphy soap and peroxide - equal parts.

I doubt that anything you used had "vinegar" in it but that will remove blueing. I use vinegar when stripping blueing on such things as cap and ball revolvers when I want to "antique" them.

You've got me stumped if it's true case hardening . . .

[MIEagle]

Thanks for your comment. As far as I know, the receivers of the Browning and Winchester 1885 High Walls made by Miroku, Japan, were real case hardened. Perhaps another section of the forum would have an idea. Thanks again.

[texasmac]

MIEagle,

Miroku (Browning's manufacturer for the BPCR) used a abbreviated potassium-cyanide process which does result in case hardening, but not to the extent necessary if softer (lower carbon content) steel was used for the receivers. Modern Browning and Winchester receivers are made from high-quality SAE 4140 steel which is heat-treated to a hardness of RC 38-42. Therefore, since additional hardening was not required, case colors were the main objective in case hardening the receiver, lever, butt plate, and grip cap. The potassium-cyanide process was used due to the reduced turnaround time and cost reduction versus the traditional bone & charcoal process, and is a well-known and widely used in the manufacturing industry.

As to what can affect the case colors, I have no idea but do know that some bluing solutions will stain or damage the colors. So I'm not surprised if some strong firearm cleaning solutions will discolor or streak it. It's been well documented that even bone & charcoal case hardening colors can be affected by strong chemicals or even weak ones if left on for an extended amount of time. I wax my case hardened receivers, which helps protect them from fading from UV bleaching and many chemical solutions.

Wayne

[MIEagle]

Thank you for your response. I'm told by a knowledgeable gunmaker that sunlight will degrade case hardening so keep it covered. I'm thinking that I may have been sloppy with the Shooters Choice Lead Remover and spilled some on the receiver, causing the discoloration that I was unaware of until too late. I will wax the receiver and barrel so that future problems won't develope. Thank you.

[oldred]

Thank you for your response. I'm told by a knowledgeable gunmaker that sunlight will degrade case hardening so keep it covered. I'm thinking that I may have been sloppy with the Shooters Choice Lead Remover and spilled some on the receiver, causing the discoloration that I was unaware of until too late. I will wax the receiver and barrel so that future problems won't develope. Thank you.


OK apparently you have a COLOR case hardened receiver and apparently Browning did Color case some of them as I finally found examples of such. But for the record and to prevent future confusion the correct term for your finish is "COLOR case hardening" or as some might call it "color cased" but the term "case hardened" is NOT a surface finish but rather the condition of the steel itself and sunlight will not affect "case hardening", it can however affect the appearance of a color cased part. When a receiver (or any steel part) is "case hardened" that simply means it is surface hardened by the addition of carbon or other chemicals through a packing/heating/quenching process to impart a thin hardened layer onto the softer steel underneath. This allows what would otherwise be a soft part to be hardened on the outside while allowing the interior of the steel part to remain soft and ductile instead of becoming brittle, basically the softer steel will have a hardened surface encasing it after the process thus the term "case harden".

MOST "case hardened" parts are simply a dull ugly mottled grey color after the process and are then polished and blued or another type of surface finish applied but "COLOR case hardening" uses a slightly different and more controlled approach with special charcoals and/or chemicals added to the mix and then is subjected to a controlled quenching process that leaves the hardened surface with the attractive coloring rather than the normal ugly grey appearance. The term "Color casing" or "Color case hardening" is what we normally use when referring to finish appearance rather than simply the hardened condition of the surface.

[Geezer in NH]

I will bet the simple green, put a cyanide CC savage fox with it in the ultra sound for 10 mins It came out shiny bright steel Uh-Oh

[oldred]

I will bet the simple green, put a cyanide CC savage fox with it in the ultra sound for 10 mins It came out shiny bright steel Uh-Oh

The MSDS for Simple Green shows Sodium Citrate as an ingredient so that could probably be the cause. Color case colors are due to a VERY thin oxidized layer and any chemical or household type cleaner that can be used to remove rust (in a sense the surface of color casing is a type of rust) or dissolve Lime or Calcium is likely to damage case colors or bluing. How much damage will occur or how fast the reaction takes place will depend on the concentration of the mildly acidic chemicals and how long the surface is exposed. As a rule never use any kind of cleaner on a firearm unless you already know exactly what's in that cleaner and if it's safe and any cleaner that will damage bluing will also damage Color case colors since both are a form of oxidation. For certain NEVER EVER attempt to clean a Color Cased or blued surface with ANY cleaner that is meant to remove rust or even rust stains and/or Lime/Calcium stains!

[Tom Trevor]

Household vinegar will strip bluing in seconds.

[oldred]

Household vinegar will strip bluing in seconds.


More like instantly!!! If vinegar is applied to a blued surface it will at least damage it before it can be wiped off and most likely strip it down to bare metal. As I mentioned earlier I lost a spot of blue on a blued cylinder and another small spot of the color case finish on the same gun when I placed the gun on a napkin lying on a picnic table. This napkin had a small piece of cooked green bean hull that had stuck to this Colt pistol, that piece of cooked vegetable took both types of finish down to the bare metal. I don't know for sure how long it took to cause this but I am sure it was not in contact with the gun metal for more than just a very few minutes.