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Everyone who has forged iron, or otherwise heated iron much past cherry red knows that it discolors at the surface. Sometimes this is a nice array of blues, greens and pinkish colors. Plunging the hot metal in various oils will sometimes augment this coloration (like what is seen on gunlocks and some decorative craft pieces)
There are times, though, when the metal should end up "in the white".
Does anyone have a better method than abrasion (sandpaper or wire wheel) to remove the black color from the metal surface? There are now a couple of products that remove rust by chemical action, very successfully, but is there something for black iron that makes it nice and shiny again?
I'm not very optimistic that there is, just asking.
M. Demetrius Abicio
(David Wills)
Saepe veritas est dura.
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I have a sealed plastic tub (that stays outside) with a muriatic acid and hydrogen peroxide mix in it. It takes off scale that would require a good deal of time and expendables if done with abrasives. An acid vapour respirator, goggles and gloves are absolutely necessary, though, even in good ventilation. I have a grate in the bottom and just a half-inch of the mixture below that - brushing the acid over the metal surface will remove the scale in moments.
The acid is then washed off and neutralized before proceeding to sanding out hammer marks. If the hammer marks are not a problem, then a light brushing or a once-over with a scotchbrite pad will see the work finished.
I hope this helps,
-Hildebrandt
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Could you send us a recipe for that solution? I'm willing to try it, and others might also be interested. All standard disclaimers apply, if I get acid in my eye, it's because I didn't follow safety rules, and it's not your fault, etc., etc.
You could send it by PM if you're more comfortable like that. Peroxide is available in many different strengths, from rocket fuel to wound wash. What do you use, the grocery store dilution?
M. Demetrius Abicio
(David Wills)
Saepe veritas est dura.
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I don't even know if the peroxide is needed, to be honest. I made that mixture for a different original purpose, and I have been reusing it. I mixed about 250ml (one cup) of dollar store variety (3%, I think) peroxide into about 1.5L (1.5 quarts) of plumber's muriatic acid. The muriatic acid lists "de-scaling" among the uses on its label, so it might do the job just fine by itself.
For applications where having part of the scale remain, i.e. on the inside of armour for authenticity and rust protection, a bit of paint or beeswax will resist the acid and protect the scale.
