Part I (because the forum software likes it that way, that's why. ;)
OK, years back I bought a P11 in good mechanical condition but with significant holster wear on the stock Hot Blued finish. Eventually I sent it off to Don "Golden Loki" to be professionally Duracoated. He did a great job. I asked for an "Aged Bronze" and that's exactly what I got.
It looked good but after some years eventually began to wear. The corners and high points were beginning to wear. I Cold Blued the barrel but, well, it's cold blue: Thin, quick wearing, and not particularly protective.
So because of the finish wear and because I'd decided I was tired of that color after these years, I started looking at my options. After much reading and research, I eventually decided that I would try my hand at Rust Bluing. Of course, I had to strip off the Duracoat. It's epoxy based so I had to use a special stripper to remove it, as detailed in
this thread.
I was, eventually, rewarded with a slide "in the white." Doesn't look very white. In fact, down right dark gray looking.
Plus the media blasting that Don did left a surface rough enough to use as a fingernail file. OK, so I'd have to sand it. The rusting agent I'd settled on is
Mark Lee's Express Blue #1, $20 + $10 S&H. OK. Anyway, Express Blue instructions recommended sanding to no more than 400 grit. I pulled out the handy palm-sander. Good thing too. Block sanding would have taken forever. Still took me an hour or more but eventually I was rewarded with a very matte slide, still in the white but a lot "shinier."
Then off we go to clean and degrease. According to my research, degreasing is an absolutely critical step.
Now I was ready for the Rust Bluing process. I got all the components ready. Research (and the advice of friends) also indicated that distilled water is, again, absolutely critical. Tap water may have minerals which would inhibit the process, or create blotchy patches (or worse). Rain water is usually acceptable. Unfortunately I hadn't collected any rain water so I bought 2 gallons of water from Wal-Mart and had it waiting for me. When I got up that morning to start my project... it was raining heavily outside. <sigh>
The manual directs that the piece be heated to between 175 and 200 degrees with a propane torch or the like. I used a toaster oven set to 200. No guess work on the temp.
Heat the piece, then wipe it with the rusting agent. Always use clean cloth or similar gloves to prevent skin oils from contaminating the work. A thin brown-red coating of rust will form almost immediately:
When a nice coat of rust has formed, put it into the boiling water for five minutes.
After 5 min., remove the piece. The boiling water will have converted the brown-red ferric oxide to black ferro- ferric oxide. Remove the piece, drain and dry immediately, and then "card" the loose black oxide off (rub it off). A friend recommends carding with paper towel, but I had better luck with 0000 steel wool, which is also commonly recommended.
[end Part I]