Frank - first phase -modeling
in Plasteline for cold cast bronze. This is my
dad so I'm making several copies as Christmas gifts
for the family.
Side and front
of finished model. The surface can be smoothed with
a paintbrush and sponge dipped in mineral spirits.
Then the head is sprayed with shellac to seal it in
preparation for the mold making.
Making the mold - 2nd layer of
silicone rubber has just been applied on this 2 piece
mold (left). One more thick layer to go, then the clay
barrier (divider) is removed and rubber mold is made
on the other side (right). I am testing some new
mold material - the pink is Smooth-On's Mold Max shore
20 and the yellow is Mold Max shore 10. Both of them
turned out to be too runny for vertical application
(even when used with a thickening agent), so I now
use Mold Max shore 30 (which is blue) for all of my
molds. It has the perfect consistency and is very strong.
When cured, the supporting shell mold
is made over the top of the rubber mold (left). This
is a fiberglass resin - light and strong (smooth on "Plasti-Paste")
. The shell mold is made in three sections to make
sure it will come off easily - one section for the
back and two sections for the front. The next day,
the mold set can be removed and is ready for castings
(right).
Mold assembled and poured. Rubberbands hold
the mold together around the knobs created for that
purpose (left). For additional support, tie the mold
tightly with non-stretching rope or sections of bicycle
tire intertube straps tied securely around the
mold. A mixture
of 90% bronze powder with 10% binder and a touch of
black pigment is poured in the bottom opening and rolled around to coat the top 1/4
inch layer of the piece. When the bronze layer has set up, the head
is filled with polyurethane resin. The pour takes 2 minutes to harden
and can be unmolded in an hour (right).
Next,
I used Tiffany green acid patina to give the piece
some added depth and color (left).
Buffed
with a dremmel tool, waxed with a layer of warm brown
wax and buffed, the piece is now ready for mounting
on its base (below).