Page 196 - My FlipBook

164 FILLING MATERIALS

the wheel, pour melted pure tin into the impression in the
sand or marble dust, thus duplicating the wheel in tin. Mount
on a mandrel on the laboratory lathe, and, while revolving

rapidly, cut fine shavings with a sharp carpenter's chisel.
These shavings, if worked while freshly cut, will be very
cohesive.
Tin is placed on the market in sheets 4 inches square,

the same sizes and numbers as gold foil, ranging numbers 2,
3, 4, 5, 6, 8, 10, 20, 30, 40, 60 and 120. It is prepared by the
manufacturer in the same manner as gold, by rolling an ingot
into strips and then rolling thinner for the higher numbers,
and beating by machinery for the lower numbers. The
number indicates the number of grains to the sheet, viz., a
sheet of No. 4 foil weighs 4 grains, No. 10 weighs 10 grains,

etc.
Tin foil, as well as gold foil (cohesive or non-cohesive)
is prepared for use in various forms by the operator or his

assistant.
The principal forms used are :
1. The Roll.
2. The Ribbon or Tape.
3. The Rope.
4. The Cylinder.
5. The Mat or Cushion.

Method of Preparing. (Either tin or gold.)
I. The Roll.— (a) Cut a sheet of foil into quarters, thirds
or halves, and place a section near one end of a smooth towel,
which has been folded lengthwise, (b) Pull the other end of

the towel over the foil, and then, bringing it in contact with it,
quickly push the towel from you in such a manner as to roll
the foil into a loose roll, (c) Repeat the process until the roll
is as small as desired (Figs. 180 and 181). Rolls may now
be obtained ready prepared by the manufacturer.