Hi Sandy --
The same book showed two ways to color aluminum. Both of them suggest the
use of lye. I have worked with lye to make soap. let me tell you it is
dangerous stuff. IMHO much worse than any acids you may come in contact
with. When working with lye protect your eyes and skin, and have no
distractions. When mixing lye with water to make solutions it will heat up
sometimes as hot as 200 fahrenheight. Use only glass or stainless steel
(never aluminum) containers, plastic is ok if it can stand the heat. (I use
the plastic Chinese soup containers that they give us with to-go orders when
I make soap. ) Keep some vinegar around in case of spills and accidents to
neutralize it. With all this in mind read on....
-- Begin Quote --
-- Steel-Gray on aluminum
Zinc Chloride 8 oz
Copper Sulfate 1 oz
Water, Boiling 32 oz
Immerse the objects until desired tone is obtained. Rinse in 2% solution of
lye (Caution!) in water, then thoroughly in clear water.
-- Near-white and matte colors on aluminum
A soft-etched, imitation anodized finish may be produced on aluminum by
dipping it in a solution of 1 tablespoon or more of lye to a pint of water.
To color the aluminum, then dip it in a solution of household dye. (Caution!
be careful with the lye. Caustic!)
-- end quote --
----- Original Message -----
From: "Sandy King" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, February 26, 2001 2:57 AM
Subject: Re: [Cameramakers] Re: Blackening Brass Rails
> Do you have any formulas for blackeining aluminium?
>
>
>
>
> >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
> >
> >
> >_______________________________________________
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> >http://rmp.opusis.com/mailman/listinfo/cameramakers
>
>
>
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