Eighteen-gauge copper should be used for this problem, and two new
operations, _viz._, raising and chasing, are introduced. After cutting
out a circular piece of copper to the diameter indicated, allowing one
half an inch extra for raising, it is annealed by heating it to red
heat under the blowpipe flame and cooling by dipping in a sulphuric
acid pickle bath. A circle indicating the inner edge of the rim is
lightly scratched, and a hard wood block is cut on the end grain to the
shape indicated in the sketch, and placed in a vise. Now holding the
copper on the block, it is raised to shape with the round end of the
roughing hammer. It is well to anneal frequently.
[Illustration: Design for a card tray]
After shaping, the design may be applied by means of transfer paper
and the lines lightly scratched on the surface. Then imbed the tray
in pitch and outline the design by following the lines with a narrow
chasing tool. Reverse the tray on the pitch and, with a chasing tool
of suitable shape, raise the body of the design to the height desired.
Reverse on the pitch again and with a flat tool true the outlines and
smooth the background. Remove from the pitch, trim the edge of the tray
if it is forced out of line, clean with pumice stone and buff.
[Illustration: Method of shaping with the hammer]
All the foregoing articles may be agreeably coloured by painting them
with, or immersing them in, a weak solution (boiling) of liver of
sulphur. If soft solder has not been used, another pleasing finish
may be secured by applying a thin coat of lubricating oil and heating
gently until the oil is volatilized. An antique green or verdigris
finish may be obtained by painting with a mixture of acetic acid and
copper carbonate. Several coats may be necessary; and it is desirable
to lacquer the surface to ensure permanency.