ASK THE ARTIST: CHRISTOPHER C. DARWAYsize limitations
For this technique, the flame needs
to cover the entire surface of the
metal to prevent oxygen from reach-
ing the surface of the copper. Use the
largest torch tip you have, and aim
the flame at a firebrick to gauge how
large of a piece of metal you can use
based on how large the flame is. You
can also use multiple torches for large
pieces if you are comfortable holding
a torch in each hand.choosing
a torch
Use a torch that will let you lower
the line pressure or control the
amount of air mixing with gas. I like
an acetylene torch, such as a Prest-
o-Lite or Smith. When I teach where
an acetylene tank isn’t allowed, I use
the EZ (ORCA) Torch with MAP-Pro
(a propylene/propane variant) fuel.
One nice feature of the EZ Torch is
the air-adjusting control ring on
the torch head. It comes with three
different-size tips; use the largest.910
11 12
What studio mistake have you learned the
most from?
“Don’t let aluminum scrap become mixed with sterling silver
scrap. I have made this mistake. The only use for this ‘exotic
alloy’ is a trip to the reiner.”
Contact: [email protected]the heat than to underfire the piece.
Quench the piece in water [7]. If any
of the Aura 22 lifts from the surface of the
copper, the piece was underfired. If this
happens, clean the copper with super
pickle (see “Super Pickle,” opposite
page), dry it, carefully lift up
the Aura 22, and paint ad-
ditional slip underneath it,
like glue. Then, repeat
the firing process.
Finishing
Pickle the piece. Place
the piece in regular hot
pickle until the pickle begins to
remove the oxides. Remove the piece
from the pickle [8], rinse it, and gently
brush it with a soft brass brush [9]. Place
the piece back into the pickle, and leave it
until the exposed copper looks pink with
no dark spots or oxides. Remove the piece
from the pickle, rinse it, and pat it dry.
Etch the copper. Apply packing tape to
the back of the copper. Place the copper
into super pickle. Within a few minutes,
you’ll see small bubbles appear on the
surface of the metal [10]. This is normal.
NOTE: Remember when I mentioned that
overheating can cause the gold to alloy
into the copper? This part of the process
depletes the copper from the surface,
leaving the Aura 22 exposed.In under an hour, you’ll see a noticeable
change in the color and surface of the ex-
posed copper. Depending on the
final use of your metal, you
can stop at this point [11].
For a deeper etch, leave
the piece in the super
pickle overnight. Be care-
ful though; a piece of
copper will dissolve if left
in this solution too long.
Remove the piece from
the super pickle, then rinse
and dry it. Your metal is now ready
to be formed, soldered [12], sawn, drilled,
enameled, or patinated without fear of the
Aura 22 coming off.http://www.ArtJewelryMag.com 41
Process photos by Christopher C. Darway.Try this
technique with fine-
silver metal-clay slip!
The process is the same
until the silver
becomes liquid, and
it coats the copper
like solder.author’s note:
Metacognition is the knowledge of knowledge,
or knowing about knowing. The technique I
describe here combines the physical ability of
metals to alloy, a paper on sterling silver granu-
lation written by John Cogswell in 1984, an old
welder’s trick of putting soot on aluminum to
find the annealing temperature, and a paper
on making pickles using household chemicals
by Bill Seeley. And, of course, the invention of
Aura 22.