Products used in this How To:
Split Glove Mold
This
type of mold eliminates having to make a two piece mold and drastically
reducing parting lines. It also helps relieve drastic undercuts
in a simple one piece mold saving time and clean up on your finished
part. We are going to show you a simple way to make a one piece
mold with virtually no seam using Dow Corning's HS III silicone
mold making rubber. We accomplish this by gluing our doll or
action figure's neck to a piece of plastic. He will now be standing
straight up.
Make
a mold box by cutting a section of a PVC pipe, plastic container
(yogurt, sour cream, etc.), wood, metal tubing, or any other nonporous
medium that will fit around the head without touching any part
of him. You are looking for approximately 1/3 to 1/4 inch gap between
any part of the mold frame (PVC pipe) and the head.
Once
you have a container that fits around the head without touching
him, spot glue it in place using super glue. You don't need to
glue it all the way around because next you will seal the mold
frame to the plastic base using Alumilite's Molding Clay. Roll
the clay out and press it on the outside of the PVC pipe/mold frame
and base plastic.
Mark
your mold box with a marker to show which side is the back of the
man's head. This will help you determine what side of the mold
you will cut to remove the master and the cast piece..
Once
the mold frame is sealed all the way around the pipe with clay,
you are ready to pour the silicone. Use Dow Corning's HS III Silicone
Rubber to make the mold. HS III has excellent flexibility and tear
strength to allow the maximum number of releases per mold. Mix
the silicone thoroughly and pour it into the mold. Allow the rubber
to cure for 18-24 hours at room temperature before demolding. Before
removing the silicone from the mold frame, make a mark on the silicone
(same spot as on the pipe) as to reference the back side of the
head. This will show you where you need to cut. After you have
poured the silicone and allowed the silicone to completely cure,
scrape away the clay and remove the plastic base by breaking the
super glued sections. To remove the silicone from the PVC pipe
you may wish to use rubbing alcohol down the inside of the mold
box (PVC pipe). This will allow the mold to slide out easier.
Once
you have removed the silicone from the pipe cut out, take a scalpel
or sharp knife and cut the silicone, starting at the neck, down
the back of the head until you get to the middle of the head as
shown in the picture below. Cut the silicone just enough to be
able to stretch the silicone and remove the master/original from
the mold. Before casting a piece, put a small piece of tape or
rubber band around the seam to prevent it from moving and leaking
while you cast. Be sure not to squeeze the mold too tightly which
would prevent the mold from lining up properly. The only seam that
will show is a small line in the back of the man's neck that goes
up to the hair line or lower portion of the back of his head. This
type of mold will leave no seam in any cosmetic area of the figures
face, ears, or nose and can easily by cleaned up by scraping with
a dull knife or even your finger nail. You may wish to clean it
up further with a light sand paper.
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