Make Your Own Plastic Molded
Items
SULPHO-PLASTICS
This plastic is particularly adaptable
for making molds and
light castings requiring tensile strength but very clear
outline. It may also be used for making ornaments and
novelties. However, as this is flammable, do not use for
ashtrays.
While the name would convey the thought
of plastic sulphur which
is an unstable allotropic form of sulphur, this is not the case,
as the sulphur acts as a bond to hold the filler together and
forms a stable material.
Interesting marble effects may be obtained
by varying the filler
used; and by substituting a small quantity of chalk to replace
some of the graphite, a very pleasing glazed surface marble is
formed.
As long as the graphite is retained as
a filler, this plastic
may be electroplated and forms a very economical base for such
work.
FORMULA: Mix thoroughly and smoothly together
25 parts of
GRAPHITE and 75 parts SULPHUR and place over heat. As soon as
the mass has melted and runs like water, remove from the heat.
In any case, a temperature of 235 degrees F. not be exceeded.
If heated about 250 degrees F. the plastic will form a rubbery
mass and will have to be cooled and reheated. In this liquid
state the plastic is ready for casting and may be poured into
smooth surfaced molds.
N.B. to heat this mixture properly, a good
even heat is
necessary. Should the heating be done by flame, the container
should be placed in a sand bath to insure an even heating
surface. The cast-iron top of a heater or stove is excellent.
EQUIPMENT: The only equipment for the above
that is required is
space enough to work in, a stove or heater, a pan to heat the
mixture in and a bench or table.
PROCEDURE: Before making any casting you
will need a pattern.
After choosing a design that fits your need, your next step is
to make the mold. Then you may start into production. If your
product requires any holes, threads or machining, this may be
done in the same manner as in working with a metal casting.
Always think of your castings as metal,
for they have metallic
properties, i.e., conduct heat, electricity and can be
electroplated. In fact, the most valuable quality of
Sulpho-Plastic is the fact that it can be used as a metal
substitute. This permits you to make products that look and are
as good and even better, in some cases, than a true metal. For
instance, to make a chrome plated metal lamp base or other metal
casting would require foundry equipment and machine shop work
and in all, a process miles out of the reach of the small
manufacturer. However, with our plastic, a lamp base, similar in
all respects, may be made for a fraction of the other cost.
ELECTROPLATING: While this can be done
at home with very little
equipment, it is advisable to have it done by a commercial
electroplater, who does it very cheaply and much more
efficiently. Electroplating is only used on expensive replicas
and is not advisable for a start.
DESIGN: The number and variety of articles
that can be
manufactured from Sulpho-Plastic is practically unlimited and to
make a complete list would be impossible. However, any article
of reasonable size and simplicity of design such as lamps,
curios, buddhas, incense burners, elephants, vases, plaques,
brooches, desk-sets, toys paper weights, etc., may be cast by
using an original or purchased article for a pattern or model -
or an original design may be patterned in clay and used to make
a mold. It is advisable for the beginner to choose a simple
article for a start, preferably solid, such as paper weights or
book-ends.
MOLDS: Molds may be made of metal or plaster
of paris. Metal
molds, however, require a great deal of skill and equipment to
produce. Therefore for the beginner, it is advisable to use
plaster of paris.
To make plaster of paris molds; first obtain
a box, wood or
cardboard will do; about an inch longer each way than the
article to be cast. Coat the inside of the box very thoroughly,
yet thinly, with stearine or sweet oil. Use this also on the
article to be cast. This acts as a lubricant and the plaster of
paris will not cement itself to either the box or the article,
if the oil is evenly distributed.
Now, next make a thick, creamy mixture
of plaster of paris by
sifting the plaster gradually into the water, stirring
constantly to prevent lumping. Let this stand a few minutes to
allow the air bubbles to escape. Pour mixture slowly over
pattern in this box to about double the thickness of the pattern.
Allow several hours to dry, then remove.
If the stearine or
sweet oil was applied properly, this will be easy. When the
mold is thoroughly dry, give it a coat (thin) of shellac and
repeat in 12 hours. Mold is now ready for use.
MOLDING: First and foremost always make
sure that you have
lubricated your mold with beeswax or stearine. Place molds on a
reasonably level surface and pour the sulpho-plastic into the
mold, quickly and smoothly. Do not pour from a height as this
will break the lubricant and leaves blemishes on the casting.
Plastic must be poured quickly to prevent cooling in folds and
thus making a poor casting. One of the big assets of
sulpho-plastics is the fact that it dries and hardens almost
immediately. There is no long wait for casting to dry.
