From Valentin Yotkov, premier chasing and repousse master:
The pitch bowl An 8" diameter cast iron bowl is our best choice.
It comes in the shape of a half sphere along with a round rubber
pad. Because of it's shape and weight, the bowl can be positioned
in any convenient angle for best comfort while working. Rubber
pads are often too large in diameter which causes the bowl to
shift easily from its position. This can be eliminated by folding
and placing an old hand towel under the pad. Using the stainless
steel bowls for chasing should be avoided as those are very light
in weight. For chasing large pieces, a large cast iron frying pan
can be used. You may also build a wood frame with the desired
dimensions and attach it to a piece of plywood. Melt the pitch in
a separate container and pour into the frame. A minimum of 3"
layer of pitch is necessary.
To prepare the pitch bowl put the pitch in a plastic bag, break
into small chunks and put it in the cast iron bowl. Set your
kitchen oven at 250F. Put the bowl with the pitch on the middle
rack over a sheet of aluminum foil. In approximately 30 - 40 min.
the pitch will melt. Depending on the actual temperature in your
oven, the melting could take a bit longer. Wait until the surface
of the pitch becomes smooth and level. Tap carefully with a piece
of wood on the outside of the bowl to force the air out of the
pitch. Add more from chunks of pitch, if necessary, to fill the
bowl up to about 1/8" from the top. Do not overfill. Avoid any
spills on the outside of the bowl. Do not attempt to handle the
hot bowl and pitch and do not leave the pitch bowl in the oven
unattended. Once the pitch is melted and ready leave the oven
door open and let the pitch air-cool for several hours.
M E T A L W E R X
50 Guinan St.
Waltham, MA 02451
Ph. 781/891-3854 Fax 3857
Jewelry/Metalarts School & Cooperative Studio