SCIENCE 
!S 
KNOWLEDGE 
KNOWLEDGE 
IS 
POWER. 
J PRACTICAL JOURNAL OF 
HOME ARTS. 
Vol. VI. 
NEW YOKK, OCTOBEK, 1883. 
No. 10. 
How To Make Rubber Stamps.— 11. 
VULCANIZATION OF THE RUBBER. 
H E plaster cast 
being now quite 
dry, our amateur 
s t a m p - m a k e r 
may at once pro- 
ceed with liis 
work. If tlie 
stami) in hand be 
a very particular 
one, or if a large 
number are re- 
quired—all to be 
cast from the 
X)laster and of one pattern— it is usual at 
this stage to soak the cast for a few 
minutes in a weak solution of ordinary 
gum shellac and methylated spirit— a few 
cents' worth of each will be sufficient. 
This mixture fills up all the pores of the 
l)laster, and leaves on it a polished and 
very smooth surface, besides making that 
fragile material almost as hard as a 
stone. But for ordinary work this pro- 
cess is quite unnecessary ; in fact, it is 
rarely, if ever, employed, unless in the 
manufacture of very expensive stamps, 
such as daters, etc., which are expected to 
last for half a lifetime. 
In (4ther case the cast is now taken 
and replaced in the frame. Take two 
pieces of the specially prepared india- 
rubber, which is supplied in suitable 
sheets, cut them to the size of the stamp 
you require, and i^lace them, one on top 
of the other, on the cast, rubbing the 
side next the plaster, and the back of the 
upper piece, with a little French chalk; 
but be extremely careful that none gets 
in betiveert the pieces. Over the top piece 
put a piece of paper, about the size of the 
rubber or a little larger. Over all place 
plate like Fig. 1, with the pins turned 
downward, and square with the edges of 
the frame. Place this '*pile" in the press, 
Fig. 2, carefully, keeping the edges 
square, and the centre of the pile directly 
beneath the screws, which you may 
tighten a little, to keep its component 
parts from moving about. 
The vulcanization of the rubber, as it is 
called, may now be proceeded with. It 
is just as well to understand the why '* 
