Service manual

Enameling
on Metal
How to Load the Kiln
1 Remove the top. Place several ½” posts on the floor
of the kiln.
2 Lay a wire enameling rack on top of the posts. If the
enameled piece is bare on the back, place the piece
directly onto the rack. If the back side of the piece is
enameled, support the piece with a stilt on top of the
rack.
3 Lower the top
onto the kiln
and fire. (See
firing instruc
-
tions, page 11.)
4 To remove the
piece, turn off
the power. Tilt
the kiln upward about 1” by lifting the electrical
box. Slide in an enameling fork and remove the
enameling rack.
5 Lower the kiln. Turn the power back on if you wish
to enamel another piece.
Preparation of the Copper
Enamels come in transparent or opaque. They can be
purchased directly from Thompson Enamel, P.O. Box 310,
Newport, Kentucky 41072. Their Lead Free Enamels come
ready to use: no enamel washing is needed.
Start with one of the many pre-shaped copper forms avail
-
able, or shape and trim the copper to your own design.
1 Heat the copper on an enameling rack to about
1400°F/760°C to burn off oil or grease. Heat the
copper to just until smoke from oil or grease stops
coming off the metal and its color has changed to a
purple-red-pale green iridescence that moves
across the copper. This indicates that the grease
has vaporized. Do not fire the copper any longer than
this point. Otherwise excess fire scale will form,
making the
next cleaning
step difficult.
2 After the copper
cools, brush
any loose scale
from the cop
-
per. Use a
brush or paper
towel, being
sure that you do not put any grease or oil onto the
copper, such as fingerprints. Clean the copper with
a 3M Scotch-Brite® pad. This pad does such a good
job that in most cases no further cleaning will be re
-
quired. Additional copper cleaning products are
available in the Thompson Enamel Catalog, includ
-
ing Sparex No. 2.
It is best to clean the copper just before you decorate it. If
you wait too long to decorate after cleaning, the copper could
get dirty again.
Decorating the Copper
Counter Enameling
Most enameled pieces should be counter enameled on
the back side. This gives the piece a much more finished
look, it eliminates a great deal of fire-scale cleaning, and it
controls the chipping and cracking that can result from the
different rates of expansion and contraction in copper and
enamel after the enamel has been fired.
Counter or backing enamel, a mixture that gives a mot
-
tled effect, can be used for counter enameling. Or you can
use regular enamel. Counter enamel is applied by the sifting
method described next.
When firing counter enamel, underfire it so that the fire
scale on the front of the piece isn’t too difficult to remove.
You can purchase a masking preparation from your supplier
to help prevent fire scale. You must place the piece on a stilt
when firing the other (front) side of the piece. The stilt pre
-
vents the back of the counter enameled piece from sticking
to the enameling rack.
Applying Enamels
Apply enamel over a clean sheet of paper so you can pour
the excess back into the bottle for reuse. Transparent enam
-
els should be applied in several thin coats. Transparent
enamels can be mixed with fairly good results. If opaque
enamels are mixed, however, a grainy effect results. The two
basic methods of applying enamels are sifting and spatula.
Sifting Enamel
Spray or brush Thompson holding agent onto the copper.
Then sift a 1/32” layer of enamel onto the copper. Use a #60
mesh sifter. If the coat is too thin, you can easily add another
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