On Sun, 29 May 2005 07:39:33 -0400, the inscrutable "C & S"
spake:


"David" wrote in message
...
liver of sulphur

Eye of Newt?

It's the most common patina for bronzes.

http://www.dickblick.com/zz605/05/
http://www.caswellplating.com/kits/metal.htm
http://www.senturyreagents.com/sulfurated_potash.htm
http://dict.die.net/hepar/

From www.finishing.com/128/71.shtml
--snip--
Jan 6, 2003

Here...

How to use Liver of sulphur
By: John A. Foutz

Liquid oxidizers (Win-Ox, Silver Black, etc.) are easy to apply but
are too easily removed. The chemical also tends to creep out long
after the work is finished unless the piece is rinsed very thoroughly.

Liver of sulphur is the most effective oxidizer of sterling silver I
know of in both cost and performance. It, unfortunately, is the least
easy to apply. It penetrates and thus is the most resistant. We
usually finish our work with tripoli then scrub it clean in hot soapy
water with a brass brush and then oxidize. This way the areas needing
to be polished can be stripped easily without having to apply pressure
on the buff that may gouge out recessed areas that are intended to
remain oxidized.

You can achieve an extremely good antiqued effect by partially
removing the oxidized surface using very fine steel wool. Next buff
the piece with a new muslin wheel without any compound. This removes
the steel wool scratches. Finish by hand rubbing with a rouge cloth.
This gives the piece a nice glow.

One ounce will make about a quart of solution. Dissolve the mineral in
warm water. Make up only what you need at one time. Both the mineral
and solution forms will stay preserved if they are kept in air tight
and light proof containers. Opaque or dark brown "medicine" bottles
are good choices. A yellow color tells you that the solution and / or
the mineral form is still potent. A clear solution with grey flakes at
the bottom means it's time to make a fresh batch.

To get Liver of sulphur to work the solution and/or the metal must be
heated. Heat the solution until the first whiff of steam appears.
Never boil it. Large quantities can be held at the proper temperature
in a crock pot. I use plastic mesh grape bags from the grocery store
to dip multiple small items. Small quantities can be heated in an old
tin or aluminum can then poured back into it's air tight container.
Also the metal can be continuously torch heated and dipped into a cold
solution to quickly do small jobs. Never dry out or boil the solution
if you use this technique. Keep it wet and dip again when steam
appears.

One can tell the right amount of time to treat the metal by observing
the color change. The desired effect is to achieve a solid blue-black
appearance. A colorful rainbow effect means that you must do one of
the following... Prolong the treatment, increase the temperature or
make the solution stronger by adding more mineral Liver of sulphur.

Over heating or prolonged treatment should be avoided at all cost.
Black, blotchy flakes will begin to appear on the metal's surface and
the oxidization will become very difficult to remove.

Rinse thoroughly and avoid skin contact. Liver of sulphur fumes are
both smelly (like rotten eggs) and toxic. Use only in a well
ventilated area and never leave the lid.
--snip--


--
If you turn the United States on its side,
everything loose will fall to California.
--Frank Lloyd Wright