When you rust blue, you coat the polished metal with an acid solution that
creates a thin film of red rust(ferrous oxide) Then you boil the metal in
distilled water for a few minutes. The ferrous oxide converts to
ferro-ferric oxide which is black. The rust is removed with fine soft wire
brushes and the process is repeated until the metal reaches the desired
color, usually about 3-5 rusting cycles.

Randy


"Dan Caster" wrote in message
m...
When you do blueing, you have to add sodium hydroxide until the
boiling point is about 280 degrees in order to get black oxide. Below
that temp. you get red oxide. So I don't think plain water will work.
If you want to try that do it with something else first.

Dan


Carl West wrote in message

Hmmm... I seem to recall something about boiling rusted items in plain
water to turn the oxides black. Ring a bell anyone?