Advertised case hardening on BP revolvers

[jdn262]

Both Pietta and Uberti have listed several of their BP revolvers as having case hardening and ask a higher retail price above the same blued model revolver. Question: Is this really true case hardened steel on the frame and hammer or just faux case hardening color effect using a chemical bath?

 

[Colonial Boy]

Scratch it and see, but do it on a well used one to keep the value or under the trigger guard, I’’d vote for some commercially quick fix.
It possibly takes extra preparation and more time in a bath so costs a bit more.

 

[jdn262]

Scratch it and see, but do it on a well used one to keep the value or under the trigger guard, I’’d vote for some commercially quick fix.
It possibly takes extra preparation and more time in a bath so costs a bit more.

Your suspicions maybe right. I looked up what it take to case harden steel and the basic process is stated as follows.

Flame or induction hardening are processes in which the surface of the steel is heated very rapidly to high temperatures (by direct application of an oxy-gas flame, or by induction heating) then cooled rapidly, generally using water; this creates a "case" of martensite on the surface.

This would be a costly additional process unless the average $50.00 U.S. cost above the basic blued revolver is a real case hardening cost in the equilalent Italian Lira money conversion exchange. I currently only have all blued revolvers so I have no way to test. I do know that real case hardening on steel is done specifically for reducing wear on a steel surface. Perhaps some other forum members reading my post can to a simply scratch test somewhere on their "case hardened" revolver and chime in with the result.

 

[64Springer]

Case hardening is done in an oven or kiln where the parts to be hardened are free from oxygen.

The parts are packed in a saggar with charcoal, bone and other charred organic material.

Case hardening is not done with an external heat source.

Taking MAPP gas to a piece of steel until it's colorful is not case hardening.

In short, it's false advertising.

 

[Nav]

The hardening doesn’t come from the heat. It comes from rapid cooling causing the steel to crystalize.
Hardening a frizzen IS case hardening. You just use the Cherry Red to hasten/ensure the rapidly cooled steel forms the crystalline structure that will spark well. I have several case hardened frames on revolvers, and I can’t really see the point other than for that look. They‘re heating and quenching just to form that patina. The mild steel on a revolver frame doesn’t actually need to be hardened. In fact, I would think it would make it less durable, not more.
My guess is that’s just the process that creates the cosmetic look.

 

[Nav]

Case hardening is done in an oven or kiln where the parts to be hardened are free from oxygen.

The parts are packed in a saggar with charcoal, bone and other charred organic material.

Case hardening is not done with an external heat source.

Taking MAPP gas to a piece of steel until it's colorful is not case hardening.

In short, it's false advertising.

In terms of the multicolored revolver frames you may be right. I have a numismatist buddy who cooks coins with that process To get a similar patina.

 

[Phil Coffins]

I do color case hardening with char coals, it can vary from a very thin skin that is colorful to a relatively thick skin of colorful hardening. What I have found is the color case on replicas is generally very thin. How they do it is out side of my knowledge. What has become apparent to me is a reasonable depth of case hardening is both wear resistant and corrosion resistant. If done on an industrial level I think it can be done well at a reasonable cost. The combination of a hard skin on a low carbon interior has proven to be very effective.
IMG_1099 by Oliver Sudden, on Flickr

 

[maillemaker]

I may be wrong, but I believe reproduction revolvers have what is called "color case hardening", but it is not case hardening at all, but merely a cosmetic finish applied to simulate the antique bone case hardening appearance. Modern steels and heat treating have negated the need for the historical process.

Actual case hardening can be accomplished a variety of ways today, but the upshot is you are allowing carbon to migrate into the outer millimeter or so of an iron object, turning it into steel. Being steel, it will then respond to heat treatment, allowing the object to have a hard outer surface while still having an iron core that is comparably tough and malleable.

Turnbull does the actual historical process to achieve the historical look and function:

Color Case Hardening - Turnbull Restoration

Examples of Turnbull Color Case Hardening. The process leaves a hard surface finish and a beautiful layer of colored carbon. Learn more about out process.

www.turnbullrestoration.com

 

[IanH]

I've done a bit of case hardening, some color-case hardening, and some faux color casing with various methods.

Casing iron is different than casing steel.

Color casing steel is mostly just for appearance and is tricky because you can't anneal the part very much afterward or the colors fade; this is where the flash-heating and special quench baths come in so only the very surface is heated to casing temperatures and not the whole piece, otherwise the frame would shatter when subjected to firing. Steel already has the carbon in it so an anaerobic heat for an extended time at absorbtive temperatures in a charcoal pack is unnecessary. I have a bunch of Uberti's products which have color-cased frames and the only thing I can verify is the finish is very thin and is a product of heating/quenching, not an acid wash or other faux treatment.

 

[IanH]

Looks like we cross-posted, maillemaker. I was going to mention Doug Turnbull in the context of how he color-cases 4140 steel in modern guns without turning them into bombs, it is a VERY different process from color case hardening iron.

 

[Nav]

That makes much more sense it’s a different process than actually case hardening a frame. When you do a frizzen you have to anneal everything but the face back so it’s not so brittle it breaks.

 

[GYJ]

The replicas are not case hardened and the colors are only done for cosmetic reasons. Of course, it hasn't really been necessary for 100yrs but we must like it.

 

[kh0456]

I own a Pietta and a Uberti 1860 cap and ball pistols. It’s just a chemical thing they do. It’s not real and can be stripped off.

 

[wiscoaster]

Nevertheless, the Pietta and Uberti finishes are really pretty resistant to wear, unlike the Traditions finish, which comes right off if you rub it too hard. At least, that's been my experience.

 

[LME]

I do color case hardening with char coals, it can vary from a very thin skin that is colorful to a relatively thick skin of colorful hardening. What I have found is the color case on replicas is generally very thin. How they do it is out side of my knowledge. What has become apparent to me is a reasonable depth of case hardening is both wear resistant and corrosion resistant. If done on an industrial level I think it can be done well at a reasonable cost. The combination of a hard skin on a low carbon interior has proven to be very effective.
IMG_1099 by Oliver Sudden, on Flickr

Nice job! You make me wish I had paid more attention to my father? He case hardened parts for wear resistance in the machine shop. I wasn't interested then and now regret not paying more attention. Some of the parts had nice marbling on them.

 

[Nav]

So, no quench on the color case hardening? Just a heat treat?

 

[maillemaker]

Nevertheless, the Pietta and Uberti finishes are really pretty resistant to wear, unlike the Traditions finish, which comes right off if you rub it too hard. At least, that's been my experience.

My understanding is that Pietta makes the revolvers for Traditions. I could be wrong.

 

[maillemaker]

So, no quench on the color case hardening? Just a heat treat?

For traditional case hardening, quenching is part of the "heat treatment".

Basically, to case harden:
1) Pack iron object in carbon-rich material and heat to high temperature to let the carbon migrate into outer layers of iron, making steel.
2) Quench object to cause steel to harden.
3) Re-heat object to lower temperature to "temper" it. This makes it less brittle and less prone to cracking under load.

It is interesting to note that one of the first, if not the first, recorded instance of this process (carburization, quenching, and tempering) was captured by the monk Theophilus in his book "On Divers Arts" where he recorded the process for making files. He wrote his book around 1100 AD.

 

[64Springer]

So, no quench on the color case hardening? Just a heat treat?

The hot parts and the material the parts are packed in get dumped into a huge container of cool water and quenched quickly.

 

[Nav]

How do you keep the hardening just on the surface then? Do you anneal the part after the quench?