Hi y'all --
Let me preface by saying that #1 I am not a chemist so I take no
responsibility for the information I am about to contribute. and #2 I have
not used either of these formulas, so YMMV and be careful, I take no
responsibility so don't sue me if you lose and eye, burn off all your skin,
your wife leaves you, your cat pukes or your dog bites your ankle or you
ruin an expensive piece of brass. All that said, here is what I have from a
pretty thick book on my shelf.
According to 'Formulas, methods, tips and data' by Kenneth M. Swezey (1969)
Popular Science Publishing Company, Inc.) library of congres card catalog
number 68-54377
-- Begin Quote from book --
Before applying any of the following formulas be sure that the metal to be
treated is absolutely clean. If lacquered, remove this finish with a lacquer
solvent or a heavy -cutting buffing compound. Unlacquored brass, copper,
and aluminum can be celaned by rubbing with a good metal polih. Wash in hot
water with a strong detergent and follow with hot-water rinse.
Many of the processes are simply artificially induced corrosion. Others etch
the metal bare. To prevent continued action rinse them i nvery hot water.
Brass, copper,and aluminum objects can them be waxed or coated with a clear
metal lacquor. Colored steel tools and hardware should be coated with oil.
--
Black on Brass
Dissolve 1 ounce copper nitrate in 6 ouncees of water and apply to the
brass. Then heat the brass to change the copper nitrate to copper oxide,
which produces a permanent black finish. Instead of heating, you may apply
this solution over the copper nitrate coating.
Sodium Sulfide 1 ounce
Hydrochloric Acid, concentrated 1/2 ounce
Water 10 ounces
This will change the coating to black copper sulfide.
--
Dull Black on Brass
Dissolve copper scraps in concentrated nitric Acid dilluted with equal
amounts of water in a glass container. (Caution nitric acid is extremely
caustic.) Immerse brass object in solution until desired depth of black has
been produuced. Remove and wash well with water. if desired, the coating can
be given a sheen by rubbing with linseed oil.
-- End quote from book. --
-- There are also ways for a golden matter antique green and several other
colors as well as plating and other such things.
-- Bradley
_______________________________________________
Cameramakers mailing list
[EMAIL PROTECTED]
http://rmp.opusis.com/mailman/listinfo/cameramakers
