LOST WAX PROCESS
(Cire Perdue)
Since 3000 B.C.,
peoples of high culture and civilization, have worked with bronze. Of all man's
artifacts, bronze and stone have proven the most durable. Modern technology and
products have accelerated the speed of producing bronze but in every other
aspect, bronze casting is still done by the lost wax process ("cire perdue" in
French). |
| The artist
gives the idea form and expression in clay or Plasticine. |
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| The making
of a negative mold is a constant challenge of knowledge and skill. The negative
mold is made with silicone rubber and a reinforced plaster mother mold. |
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| The
negative mold then produces a positive duplicate of the original work in
wax. |
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| The wax is
then chased and spurred. |
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Once the
wax is spurred;
it is invested in ceramic shell. |
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The
process involves as many as ten to twelve dips into a coaguloid or binding
agent . . .
. . . after which a coating of
silica sand is applied and allowed to dry in between coats. |
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| After
applying the ceramic shell, the wax is exposed at the cup and is heated to melt
the wax so that it will run out. Then the shell is heated further to a
temperature of 1700 degrees Fahrenheit to burn out any wax residue. |
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| In the
foundry, the bronze is molten in a furnace and is then poured into the ceramic
shell when it has reached a temperature of 2850 degrees Fahrenheit. |
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After the
bronze has cooled and hardened, the ceramic shell is removed . .
.
. . . and the raw casting emerges. |
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| With tools,
the spurs (pouring channels) are removed. The casting is then welded, chased
and sand blasted. |
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| The patina
(color) is applied using chemicals and acids, sometimes under heat, either by
immersion or brushed on to achieve the requested patina. |
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| A protective
coating is applied to protect the patina and to seal the bronze. The casting
now has achieved its final appearance. |
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CLASSES:
The artist offers classes in Saskatoon,
Saskatchewan, Canada twice a year usually from January thru April and September
thru December. The classes are twelve weeks with sessions once a week lasting
three to four hours. Classes are in portrait creation, figure sculpture, mold
making and casting to plaster. The artist also offers workshops and
demonstrations working from life.
Please
Contact HOLTKAMP Fine Art Bronze for further
information.
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