Re: ATM Copper Alloy Passivation

[Anthony Stillman <atmer@flash.net>]

(just a few) Copper Patina Recipes

dull black

Sulphurated postash   2    oz
Ammonium hydroxide    0.25 oz
Water                 1    gal
Temperature           21   C   (70F)


red to brown

Sulphurated postash   2    oz
Sodium hydroxide      3    oz
Water                 1    gal
Temperature           76   C   (170F)


brown

Ferric Nitrate        1    Tbsp
Water                 1    qt

Mix solution and spray on.  Air dry.  Apply several coats as needed.


brown

Peanut Oil

Coat copper with a thin film of oil and heat the copper with a low
temperature torch until the oil begins to smoke.  Then show it a picture of
a dead cartoon camel and tell it to quit.



Prior to applying a patina, the metal should be cleaned and air dried.  A
scotch brite pad works well for cleaning.  After diping, allow the metal to
air dry or use sawdust.

Sulphurated postash is also know as liver of sulfur.

Several of the chemicals above if improperly used or properly misuse can be
really nasty.  Work in a well ventilated area and be careful.  Also,
commertial patina solutions are avalible from jewlery fabrication outlets,
many of which are accessable on the net.  I have worked with Rio Grande for
years and recommend them  http://www.riogrande.com/

Anthony