at the base. The upper part of
the press, or the platen, is also of iron, cut so it can be swung

[Illustration: Fish Kettle Vulcanizer]

off the bolts, rather than by removing the nuts and lifting it
off. String a half dozen nuts, larger than those which screw on,
on each bolt, so that when the upper nut on each is screwed to the
extent of the thread the pressure will be communicated through the
nuts wedged in between the platen and the upper nut. The bolt
holes in the platen should be directly over those in the base.
Distance pieces of an exact thickness should be provided for use
on the base; these serve to keep the pressure even.

In preparing the mould, if type is to be copied, use rather large
type with wide spaces and set up with high quads and spaces, or
the type faces may be filled up by rubbing with either wax, or
soap, lightly brushing off any that remains loose. The type so set
should be locked into a frame. This may be made of two pieces of
wood bolted together at both ends, or of printer's furniture.
Place it on a flat surface (marble is good, but any perfectly
smooth surface will do) and place distance pieces 1/8 in. higher
than its upper surface on either side of it. Apply olive oil to
the type faces and wipe off any excess. To form the matrix or
reverse of the model, take a piece of iron larger than the
inscription to be copied, and spread upon it to a depth of 1/4 in,
a putty made by mixing plaster of paris and water to the right
consistency. By means of a table knife spread the plaster smoothly
and then invert the plate upon the model and press down until

[Illustration: Vulcanizing Press for Rubber Stamps]

the distance pieces are struck. Let it set 10 minutes and then
remove. If care has been taken the matrix will be perfect. After
it has thoroughly dried, preferably in an oven, saturate it with
an alcoholic solution of shellac to strengthen it.

Cut a piece of smooth rubber, large enough to cover the matrix,
from the sheet, throw this into a box of talc, or powdered
soapstone, so that it receives a coating on both sides; dust a
little of the powder over the matrix, also. Place the press on a
support over a gas burner; or a kerosene lamp, and apply the heat.
Place the matrix on the base of the press, dust off the piece of
india rubber and place in the press upon the matrix and screw down
the platen. Heat the press to 284 deg. F. and keep screwing down
the platen so that the rubber, now soft