January, 1911 
are easily removed. Proceed as di- 
rected for the one piece mold and 
this will give you the first half of the 
mold. Reverse the model. Remove 
the clay, fix your frame (not forget- 
ting to grease the plaster), pour 
plaster to the top of the spare and 
this will give you the other half of 
the mold. 
The only difference between a 
two- and a three-piece mold is that 
the bottom of the latter is made sep- 
arately. So below the bottom of 
the model an extra piece must be 
provided from which to form the 
toot. This can be made of almost 
any material, clay answering very 
well, but it must be removable. In 
form it is a truncated cone, the top 
the exact size of the bottom of the 
mold, the bottom a little wider. In 
the outline sketch, Fig. 2, the part 1 
is called the “spare,” which enables 
the thickness of the clay which has 
formed on the walls of the mold to 
be determined. Notice that the 
spare is a little narrower than the 
top of the model. 
Although a little troublesome to 
make, thin plaster slabs cut to the outline of the model, to 
replace the building up with clay, give a perfectly smooth 
surface, a great desideratum in molds, as the cleaning after 
use is reduced to a minimum. These must be well backed 
with clay so as to withstand the pressure of the plaster. 
Surround with a fence and make the two halves as before 
explained. Having obtained these, reverse the whole, take 
out the false bottom, cut notches on the bottom of the two 
halves and having fixed the fence so as to project from one 
to two inches, according to the size of the piece, it is then 
ready for making the mold for the bottom. 
Before using, these molds must become thoroughly dry. 
This being attained, take a large brush or sponge and paint 
over with. slip 
the whole surface 
of the inside of 
the mold. If the 
halves are per- 
pendicular tie 
tightly with 
strong cord. The 
notches are not 
sufficient to hold 
them. 
Kour ‘slap 
should be fairly 
thick and _ with- 
out lumps. It is 
best to strain it | 
into a large jug § 
or can through a 
colander. I find 
an ordinary wa- 
tering pot a con- 
venient utensil. 
Having your 
mold _ properly 
fastened and 
painted inside, 
the slip in good 
condition, pour 
the slip steadily 
Pouring the slip into the mold 
Preparing to build up the two halves of the mold about the model. 
AMERICAN HOMES AND GARDENS 23 
into the mold until it is quite full. 
The plaster will absorb some of the 
water, indicated by the fall of the 
slip in the mold. Fill this up as 
many times as is necessary until 
sufficient thickness of clay has 
formed on the sides of the mold. 
This is ascertained by taking a tool] 
or piece of soft wood and scraping 
away a morsel of the clay at the top 
of the spare. Having arrived at this 
take the mold in your hands, being 
careful to handle it so that the bot- 
tom mold does not move, and empty 
out the slip that remains. Put it 
aside to dry and in a few hours the 
“cast”? piece can be removed from 
the mold. Turn it upside down and 
take off the bottom mold, lay it on 
its side and remove the two halves, 
being careful to lift straight, or the 
edge of the mold may scar the piece. 
Place the clay piece on a plaster bat 
and allow it to dry. 
When dry enough to handle, with 
a sharp knife cut off the spare and 
trim evenly, and also trim down the 
seams, smoothing to a finish with a 
silk sponge. Keep this free from 
clay by constantly rinsing it. Do not use the sponge more 
than you can help, relying more on the knife. 
If you cut out a section of one of these cast pieces you 
will see an absolutely uniform thickness, whilst the spare 
section is uneven because at times the absorption by the 
plaster was checked because the mold could not be kept 
full the whole of the time. So necessarily the one-piece 
mold being made without a spare will be a little thinner 
at the edge. Cast pieces shrink more than those made by 
hand, but will stand a harder fire. 
If the piece is to be fired without decoration it must be 
bone dry before putting it in the kiln. If intended for deco- 
ration it can be kept in good condition for quite a time, by 
Wrapping a damp 
cloth round it 
and keeping in a 
damp place. This 
clay decorating is 
extremely fascin- 
ating and will be 
dealt with later. 
If in removing 
the piece from 
the mold it does 
oe Gem ain re 
freely, the latter 
is probably too 
hard, that is, it 
contains too 
muse hee eplaster- 
First mold im- 
pressions are us- 
ually failures, be- 
cause the mold 
has a certain 
amount of grease 
on it and this pre- 
vents absorption 
by the plaster. 
But the first cast- 
ing removes this 
grease. 
