Handgun Blues


Apprentice Nick Derr works parts through the hot “bluing“ process which
treats carbon steel with black oxide. Lots of protective gear and ventilation is required.

The process of bluing firearms may have changed a bit in the last 300 years but the appeal to shooters has not. Bluing is still the most popular finish for fine handguns hands down. Like walnut grips and real leather holsters, bluing evokes deep emotions from gun aficionados like a fine Scotch or a Cuban cigar.

Nothing can compare to a blue S&W wheel gun or a Colt semi-automatic. Both Colt and S&W produced some of the best blue pistols in the world. The Colt Python with its high polish royal blue finish is the pinnacle of a blued handgun.

A finished Colt 1911 slide after blasting and polishing.

Bluing Setup

I’ve wanted to do my own bluing for a long time, but shop space was not available. I finally made the leap to accommodate bluing in a separate shop, more on this later.

Two years ago, before the world stopped spinning due to the pandemic, I meet up with Walt Smith owner of Du-Lite Corporation at the SHOT Show in Las Vegas. Du-Lite of Connecticut is an OEM supplier of bluing salts and solutions to many manufacturers, starting with Colt in 1939.

Prior to 1939, Colt used a charcoal bluing process which produced some of the best bluing in history, but the amount of labor and time involved necessitated a change to “hot salt” bluing or “black oxide” bluing which is the process used by the industry today. Bluing is really a controlled “rust” process. It can be done a number of ways. Each can produce a great finish based on the quality of the gunsmiths’ metal preparation
For the small shop like mine Du-Lite offered a one-stop shopping solution. They make the bluing tanks and burners custom to fit the need of the user ranging from the one-man operation to full-scale production set ups for manufacturers. My set up is comprised of five tanks. One for cleaning, two for bluing and two rinse tanks on a custom stand. There are also three propane burners, one each for the cleaning and two bluing tanks. Walt recommends two tanks for bluing — each running at a different temperature to accommodate some different steel material types.

Handy aluminum sanding blocks by Harrison Design makes sanding flat
areas easy and helps keep sharp edges. Greg has one for every grit of
paper he uses in the shop.

The Process

Bluing, a hot process at 290 degrees, produces steam vapor. This vapor contains salt. Salt is corrosive to any metal it comes in contact with — why I could not blue in my shop. The metalworking machinery could all be damaged by salt exposure. I was lucky enough to construct an outbuilding for bluing. Even so, I added wheels to the bluing tank racks to move it outside into open air.

Ninety percent of bluing firearms is metal preparation. The level of blending, sanding and polishing will show through after bluing, so much work must go into metal prep. Unlike spray-on coatings, bluing will not hide scratches or tool marks. Colt spent hours on each Python and it shows in the finished product.

I use a number of sandpaper grades wrapped on blocks from Harrison Design that allow me to keep the flats smooth with crisp edges. Motorized buffers can kill rollmarks on a pistol if used too aggressively. Since I’m starting out, I am sticking to hand sanding. I start off by glass beading all the “round” area that will result in a “matte” finish. Next with 200 grit paper I remove scratches and tool marks working progressively to finer grits until I get the level of finish I want.

After a few hours or more of prep I hand the project off to my son Nick, an American Pistolsmith Guild apprentice, for the bluing. A consistent high-quality finish is everything to the custom gunsmith. So, it makes sense to have one person do it each time and he likes the process.

There are some great bluing services out there if you can’t do it yourself. Glenrock Blue in Wyoming or Turnbull Restoration in New York. Both offer a variety of polishing levels. Turnbull offers charcoal bluing which is a large operation not done by many but the envy of everyone.

For more info: HarrisonCustom.com, Du-Lite.com

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