DIY Network

Creating a Wax Replica Learn how a wax replica is created. From "Trade School" episode DTRS-310

Foundry apprentice Jeff Herndon branches out and learns a time-honored "lost wax" method used to cast a sculpted image into timeless bronze.

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Materials:

hot wax
paint brush
hot air gun
hot penknife
rasp
putty tool
abrasive pad
hot pad
hydrogen torch
ceramic liquid/sand
steel wire
wire cutters
kiln
bronze ingots
induction furnace
steel rod/paddle
ceramic crucible/pulley hoist
hammer
plasma cutter
sandblaster
TIG welder
assortment of grinders/attachments
hydraulic jack
protective eyewear
heat resistant clothing
welding gear

The lost wax method works by first replicating an original sculpted image in workable wax. A ceramic shell is built up in layers around the wax replica, creating a heat-resistant mold. The term "lost wax" refers to the act of melting away all of the wax leaving only the ceramic mold, into which molten bronze is poured and cooled, forming a bronze replica.

Figure A

Jeff's journey begins as he receives a latex rubber mold (figure A) of "Corn Girl", an original sculpture by artist, Glenna Goodacre. Formed in two connectable halves and surrounded by thick plaster for rigidity, the mold represents a reverse image of the sculpture.

In this first segment, Jeff creates the wax replica of the sculpture.

Safety Note: Always wear protective eyewear when working with hot wax.

1. Jeff starts off in the wax room of the foundry, where he uses the mold to create a hollow wax replica of the piece. Here, hot brown wax is held in vasts, each kept at specific temperatures for different degrees of viscosity (figure B). Jeff paints the hottest of the waxes into the smaller crevices of the mold (figure C). The thinner viscosity of this wax allows it to run and fill in the finer details.

Figure B

Figure C

2. Once the image surface is completely coated with wax, Jeff seals the mold halves together with bolts (figure D).

3. Jeff steadies the mold as another foundry worker pours the coolest and therefore thickest wax into the opening (figure E). Before the wax cools too much, Jeff rolls the heavy mold around to evenly distribute the wax over the inner surface. Once the wax is built up to the proper thickness, Jeff allows it to cool, and then removes the latex mold revealing an unrefined wax replica of the original.

Figure D

Figure E

In the following segment, Jeff demonstrates the art of wax-chasing as he repairs slight imperfections in the replica.