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Heat-Patination Technique [was "Depletion Gilding"]


#1

A couple of people wrote me off-list asking for more on
the heat-patination technique taught by Rachelle Thiewes so here it
is:

Depletion gild the sterling silver thoroughly by repeating the
heat/pickle cycle at least three times until you have a pure white,
fine silver surface. Tip: Use baking soda as a cleanser before
heating the first time and after each cycle – and then keep your
fingers off of the metal! You will get a much more even layer of
fine silver.

Use a file or other abrasive means (i.e., flex-shaft tools) to
abrade away the fine silver in whatever pattern you desire. The
trick is to get down to the sterling and you’d be surprised how much
filing you have to do. Until you get used to this you may find you
haven’t gone deep enough and will have to refile. Tip: Filing works
well on a curved surface (Rachelle Thiewes uses this technique with
her spiculum hollow-forms). On a flat surface, use abrasive wheels
or you could stamp the sheet and then file off the raised parts.

Clean the metal again with baking soda and handle by the edges only
(or use a tweezers).

Position the metal on your soldering surface so that it’s standing
on end – in the air, in other words. If it’s sheet, for instance,
you could use a third hand to hold it in one corner. If I remember
correctly, for her spiculum forms, Rachelle just stuck one point into
a magnesia-type block so it stood up vertically.

Now comes the trickiest part. Use a soft, reducing flame, not too
close to the piece. Start heating at the very top and then, when you
like the color, move down the piece gradually until the color has
developed completely from top to bottom. If you move back up to the
top of the piece again, you will most likely mess up your result and
have to refile. This may take a little practice but it’s well worth
the effort.

QUENCH IN WATER! If you’re like me, it’s second-nature to throw hot
metal in the pickle. If you do that at this point, the black oxide
that you’ve worked so hard to create will be removed and you’ll be
back to filing. I should know – that’s exactly what I did the first
time!

If the pieces are hollow forms, let them dry out for 24 hours.
Regardless, be sure they’re completely dry before moving on to the
next step, which is to seal the surface. Unless you plan to use the
metal in a design that completely protects it from abrasion, sealing
is essential, since the black oxide layer is thin and easily
scratched.

There are various ways to seal the surface. Check the Orchid
Archives for several threads on this subject. Commonly used are
acrylic sprays, lacquers and Future acrylic floor wax. Whatever it
is you use, be aware that it will darken the appearance of the
patina.

Rachelle’s sealer of choice is Renaissance Wax which is a clear
whitish liquid, very durable and doesn’t flake or peel. Her method
of application is to shake the wax; apply it with a cotton ball; let
it sit for 2-3 minutes; buff with a soft cloth and then rewax. She
applies 5-8 layers of wax (but keep in mind that her spiculum forms
are used in a way that they are constantly bumping against each
other). Tip: Keep the cover on the wax whenever possible. Tip:
Once you start waxing with Renaissance Wax, you must finish the
whole process. If you let the piece sit for a couple of hours and
then apply a new coat of wax, it will remove the old coats of wax and
the patina as well! (One of its functions is to protect; the other
is to clean.)

I tried to find a good image of Rachelle Thiewes’s heat-patination
work on line and this is the best I could come up with:
http://www.utep.edu/arts/metals.htm. Unfortunately you can’t
enlarge it but at least you can make out a few of her striped,
heat-patinated spiculums. Anyway, if some of you decide to dry this
process, do let us all know how it turns out. Good luck and have
fun!

Beth