Replies

On the kind of firearms you buy at Walmart, yes, you no longer see it. Most of what you see these days on cheaper firearms is a spray-on finish or parkerizing of some sort.

On the kind of firearms that cost $3K and up? Bespoke shotguns and rifles?

Oh, no, it never went anywhere. And it won’t, either.

Here’s why you might not want to do hot caustic blueing:

1. You have any parts that are soldered or brazed on the gun. On fine shotguns, for example, the ribs are soldered on.

2. You have a gun that you’re not going to completely disassemble to blue.

3. You don’t want to set up a set of tanks for hot blueing.

When you’re making a firearm for someone who has been waiting for a year or more for their gun to be completed, and they’re paying $3K to $10K (and up) for it, then waiting the two to three weeks for a slow rust blue job isn’t that much of a hardship.

For the guy who bought a used gun for $400 that is all banged and scratched up, he’s not going to wait the three weeks, nor pay the money, for a slow rust blue job.

For those who want a faster rust blue job, there’s chemicals like this:

http://www.brownells.com/.aspx/pid=7604/Product/BELGIAN_BLUE

The description given in the product is a “fast rust blue” but it is still in the category of “rust blueing.”

Here’s a video from Midway USA doing fast rust blueing. Larry is calling this “slow rust blueing,” but he’s wrong. This is “fast rust blueing” because you can be done in, oh, four hours.

Slow rust bluing is very different, and involves a “sweat box” and several weeks of attention.

Here’s one of the chemical mixtures for slow rust blueing:

http://www.brownells.com/.aspx/pid=22820/Product/CLASSIC_RUST_BLUE

If you don’t like buying a solution, you can find references to the slow rust solutions in older gunsmithing books (ie, any book published before 1960 should contain something on SRB).

In SRB, you have a “sweat box” made of plastic-lined wood that can be closed to be air-tight-ish into which you put the part. A 100 watt light bulb is placed at the bottom of the sweat box, and above that, you have a pan of nitric acid. The heated acid gives off corrosive fumes, which coat the part evenly.

Every three to four days, you pull the parts out of the sweat box, card them off and put them back into the sweat box. The total process might take as long as three+ weeks.

The biggest reason why the market got away from rust bluing wasn’t the result: it was the time involved. You can’t do rust blueing in huge industrial processes. You can do hot blue jobs in industrial lots - once the surface prep and degreasing is done, you just move the parts from tank to tank to tank in sequence and you get the results you want. There’s no carding between coats.

The reason why rust blueing fell out of favor was never the results. Genuine slow rust blueing is the most durable of all types of blueing. Lots of time spent in corrosive fumes means that the black rust has lots of time to form and become more solid.