Rust bluing, temperature and humidity

Olle · 05-11-2010, 09:38 AM

That aquafortis solution sure sounds interesting, it appears to be similar to one of the formulas in Angier's book (starts with a "Z", can't remember the name of it right now...). I have also seen some comments saying that Mark Lee’s gives a slightly blue color, but haven't tried it yet. I spoke with a gentleman at a gun show a while back, and he was somewhat reluctant to give me the whole story, but one thing he told me was that he rusted at a temperature around 95-100F so this is one of the baselines for my experiments.

I have had a problem with the reddish color as well, and I sure ain't a chemist but this seems to be caused by the quality of the water. From what I have gathered, there are basically three kinds of oxides: A somewhat unstable red ("regular rust"), a more stable black (the kind we want), plus a stable, red oxide that can occur if you boil in water that contains certain minerals. I have boiled in tap water with mixed results so I assume that the water quality can vary. To be safe, I have started using distilled water, it's cheap insurance at 85 cents/gallon.

I have experimented some more with my rusting cabinet, and I did get some very encouraging results. By cranking it up to about 90-95 degrees, I can get what I consider a good rust (black with a distinct hue of red, that's where I usually want to boil) in about 30-45 minutes. I kept the humidity at 40-45%, as anything more than that seems to cause condensation on the parts.

I use two heat sources: One cheap cooktop from Wallyworld to get it up to temperature quickly, and one thermostat controlled IR-lamp from Petco (look in the isle where they keep the reptile stuff) to maintain a constant temperature. I would like to get a steamer, but for now I simply spray some distilled water on the cooktop to adjust the humidity. The cabinet is a simple plywood box, with plexiglass panels in the door so I can easily watch the progress. I might post some pictures of the setup later, once I have figured out how to use it.

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05-11-2010, 09:38 AM	#4
Olle User Join Date: Feb 2010 Location: Tennessee Posts: 1,149 Thanks: 159 Thanked 664 Times in 318 Posts	That aquafortis solution sure sounds interesting, it appears to be similar to one of the formulas in Angier's book (starts with a "Z", can't remember the name of it right now...). I have also seen some comments saying that Mark Lee’s gives a slightly blue color, but haven't tried it yet. I spoke with a gentleman at a gun show a while back, and he was somewhat reluctant to give me the whole story, but one thing he told me was that he rusted at a temperature around 95-100F so this is one of the baselines for my experiments. I have had a problem with the reddish color as well, and I sure ain't a chemist but this seems to be caused by the quality of the water. From what I have gathered, there are basically three kinds of oxides: A somewhat unstable red ("regular rust"), a more stable black (the kind we want), plus a stable, red oxide that can occur if you boil in water that contains certain minerals. I have boiled in tap water with mixed results so I assume that the water quality can vary. To be safe, I have started using distilled water, it's cheap insurance at 85 cents/gallon. I have experimented some more with my rusting cabinet, and I did get some very encouraging results. By cranking it up to about 90-95 degrees, I can get what I consider a good rust (black with a distinct hue of red, that's where I usually want to boil) in about 30-45 minutes. I kept the humidity at 40-45%, as anything more than that seems to cause condensation on the parts. I use two heat sources: One cheap cooktop from Wallyworld to get it up to temperature quickly, and one thermostat controlled IR-lamp from Petco (look in the isle where they keep the reptile stuff) to maintain a constant temperature. I would like to get a steamer, but for now I simply spray some distilled water on the cooktop to adjust the humidity. The cabinet is a simple plywood box, with plexiglass panels in the door so I can easily watch the progress. I might post some pictures of the setup later, once I have figured out how to use it.