by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5

Diana model 23 air rifle Diana 23 was a find on Gun Broker. The finish is bad but the gun works well.

This report covers:

  • An update
  • Step 1
  • Rust
  • Step 2: To buff or not?
  • Pits
  • Steel wool
  • I’m not done prepping
  • Cold blue

Many of you are interested in working on vintage airguns. To this point, I’ve shown you how to tune several spring-piston guns and I’ve touched on the subject of cold bluing, but I have not discussed it in detail. This series will go into the refinishing of the metal parts of a springer, including how to apply a deep cold blue that lasts.

An update

The last time we looked at this Diana model 23 breakbarrel, I’d disassembled it and shown you all the bad spots. I said then my plan was to refinish the rifle. Today, we begin by cleaning the parts. I’m only showing the spring tube, but all the steel parts are treated in the same way.

I’m going to tell you everything I do to the rifle, but not in great detail. If the detail is important, like getting a good blue with a cold blue product, then I’ll elaborate; but I doubt you want to read about every stroke I take with the sandpaper.

Suffice to say, the finish on the metal parts of this rifle looked poor when I acquired it. Just look at all the pictures in part 5. But that was nearly all the bad news. The wood stock looked okay. Not swell — just okay, but that means I don’t have to do anything to it. The world of fine wood craftsmen can breathe a little easier.

And the gun tested pretty good for power. These Diana model 23s were youth airguns and never had even the power we sometimes scoff at in vintage guns. The .177-caliber JSB Exact RS dome averaged 452 f.p.s., which I thought was pretty good. And, I noted that the breech seal was flat and gouged out, so with a new seal it ought to go even faster.

Normally, my inclination is to overhaul an airgun without giving its appearance a second thought. But several readers had been discussing the best ways of applying cold blue products, so I thought I would refinish the metal on this gun for you. I also bought a few new parts that will be applied when the time comes.

Step 1

The first step after disassembly is to remove all the old finish. If there’s rust, as there certainly was on this rifle, remove that as well. The metal on this rifle appeared to have had its blue partially removed at some time in the past, because the patches that remained were not caused by honest wear.

I applied Birchwood Casey’s Blue and Rust Remover (get it online or at any good gun store) to all the metal surfaces with a cotton swab. The old blue didn’t come off fast; but with repeated swabbings, it did go away. Getting it off the spring tube took about 30 minutes. I then sanded the surface with 180-grit and 320-grit flexible sanding blocks. That took off all the remaining blue and all of the rust.

Diana 23 spring tube
All the old blue had to be removed from the spring tube.

Diana 23 cap off
This is the rust that had to be removed.

Diana 23 spring tube cleaned
And this is how the metal looked when all the rust was gone.

Rust

When I came to the rusty areas, there were two different types. There were areas of surface rust that simply wiped away with one or two swipes of the sanding blocks. Then there were a few places where the rust was deeper. These were scaly and built up, as if the surface of the steel was boiling away. And I guess that’s right, because that’s what deep oxidation (rust) does — over time it bubbles away the structure of the steel.

In these areas, I had to sand longer and harder. The blue remover is also a rust remover, since that is what bluing is — a form of oxidation. In these tougher areas of rust, I saturated the metal with the solution and came back repeatedly with sandpaper. Saturate and sand — again and again. In these areas only, the metal is pitted.

Step 2: To buff or not?

When the steel was cleaned of all blue and rust, I had to make a decision. Did I want to buff the metal to a high shine using a buffing wheel, or did I want to work it up by hand? Buffing produces a beautiful mirror shine, but it takes skill to buff a gun part and not change its shape, round the sharp corners or obliterate the stamped letters and numbers. I do not have the skill, so I decided to do the work by hand. That would be slower, but also more under my control.

Pits

When you remove the heavy rust, the metal underneath is often pitted to some extent. The question becomes, “Do I try to buff down to smooth metal, or do I leave the pits?” This is a question of personal taste, but I’m on the side of leaving the pits. There’s a way of removing these pits, and I’ve shown it to you in the past. You can weld new metal into the pits and grind/file/sand down to smooth metal again. Top restoration companies do this as a service, and you can pay thousands of dollars for it because of all the labor involved.

Diana 23 pits
These are minor pits in the metal. I advise leaving them alone.

Nelson Lewis combination gun Otho welded gun
Both these guns were equally pitted. My friend Otho welded the top one and filed the surface flat, then had the gun refinished. It looks perfect! This job took one year of his spare time — probably a man-month of effort!

If you blue over the pitted metal, the pits won’t show as much. That’s why I recommend not grinding down the metal. Few people are skilled and patient enough to do a good job. While small pits won’t show up, any change in the contour of the metal caused by excessive buffing and grinding will stand out prominently.

Steel wool

The first thing I did was buff the spring tube with 0000 steel wool. Our friends in the British Isles call this steel fur, which is a more accurate name in this case. This extremely fine product was able to shine the spring tube to a nice level. I could have called it quits at this point and simply cleaned all the other parts the same way, then applied the cold blue. But I want to take this project farther, because all the work that’s put in now will be reflected in the depth of the final finish.

Diana 23 Winchester markings
This is what the Winchester marking on the spring tube looked like before I began.

Diana 23 Winchester marking
And this is how the Winchester marking looked when all the rust was gone.

I’m not done prepping

The next step is to sand the metal parts with sandpapers of progressively finer grits — 400, 600, 800, 1000, 1200 and 1500. After that, I’ll polish the tube with steel polish and see where that takes it. If it isn’t shiny enough, I’ll hit it with some 2000- and 3000-grit sandpaper and polish it again.

Cold blue

When I feel the metal is sufficiently smooth, I’ll apply Blue Wonder cold blue to all the steel parts. Blue Wonder is different than any other cold blue. It’s tougher, deeper and blacker. It’s not simple to apply, but it is straightforward. When this is all done, this little Diana will hopefully shine again!