Mixed Waxes with Air Bubble Problems
Mixed waxes are often used for stone in place castings. The usual
mix is 50% Aqua flake wax and 50% Blue plasto-wax which provides
excellent shape memory in the wax patterns. Occasionally air bubble
defects will be noticed in the wax patterns. On checking the
compressor, air lines and moisture traps on the wax pots to insure
no source of moisture is getting into the wax pots you may find
yourself at a loss to discover the source. If you are mixing the
aqua flake wax and the blue plastowax in the wax pots by combining
the waxes in each wax pot by melting and stirring, you may be
stirring air into the wax creating bubbles.
Away around Ns problem would be to use a cooking pot of a size
that would fit under the vacuum unit in the investing area and a hot
plate or stove. Weigh the exact portions of each wax to fill the
cooking pot. Heat the wax until it is thoroughly melted and stir it
well. Move the cooking pot filled with wax to the investing area and
place on a heat resistant pad under the vacuum unit. Seal the unit
and turn on vacuum for 2 to 5 minutes, which will pull any trapped
air to the surface. Shut off vacuum and open the unit giving I shot
of silicone mold release spray to break the bubbles on the surface
of the wax. The wax can then be poured or ladled into muffin or
cupcake pans and allowed to cool. The pre-mixed wax muffins can then
be used to fill the wax pots. We tried this with one of our
customers and it worked well. The company was also having some wax
problems previously because they were eyeballing the weight of each
wax and by weighing the mix of waxes exactly, a more uniform wax mix
was obtained.
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