Color Case Hardening

A used car salesman once told me, “Paint sells.” To paraphrase in regard to firearms, “Color case hardening sells.”

- Mike Venturino

That’s in today’s marketplace. In the old days, I suspect attractive colors were a byproduct of hardening rifles’ and revolvers’ steel or iron receivers for safety’s sake. Today, steel can be plenty hard and therefore safe without color case hardening, so it is applied more for cosmetic purposes.

There are two basic types of color case hardening. One is done by a chemical process using cyanide. The other method consists of packing the part in a dry mixture, baking it to very high temperature and then quenching it suddenly in water. This second method is called pack hardening. It’s a lot more complicated than this paragraph might indicate.

Over a year ago at a Montana gun show, I was browsing the aisles and came across a gunsmith’s display of his firearms restoration work. Among the items shown were examples of his color case hardening, and to say it was attractive would be an insult, so I stopped to visit. His name is Al Springer (Snowy Mountain Blue, 816 West Fork Road, Moor, Montana 59464; smbgunrestorations. com), and since that first visit, we have become friends. With a bit of timidity, I asked Al to explain his pack color case hardening process, of course without disclosing any trade secrets. To this Al replied, “It’s an art that should never be lost, so I have no secrets.” He also stressed to me that his methods are not the only way to pack harden steel, but he has had success with them.

Here’s how he proceeds: Of course, getting the parts ready comes first. If they are new, as in never previously color case hardened, he polishes them with 400 grit emery cloth. He feels it gives a better surface. However, if the parts have previously been color case hardened, he first anneals them in wood charcoal heated to 1,375 degrees Fahrenheit for a half hour. After cooling overnight, they get the same polish treatment. Lastly, all parts are thoroughly cleaned with acetone.