Creating Skipper II
A Photo Journal Page 2
(click on photos to see enlargements)
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The
completed molds are sprayed with a ceramic coating, which
will prevent the molten metal from penetrating the sand mold.
Zircon, a very high-temperature refractory material, is mixed
with alcohol for this purpose. It is sprayed on the mold and
then the alcohol is burned away (below).
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Putting
the mold together (below). An adhesive is put down between
the halves, and the cope is lowered onto the drag (left).
The halves are then strapped together and weights are placed
on top (right) to ensure that the halves hold together to
form one whole casting cavity.
When
the molten metal is poured, a lot of hydraulic pressure
will be trying to force the mold apart. So force in the
form of lots of weight is used to counteract this pressure.
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| Heating
the metal. Gray iron is the main metal used to create Skipper
II. Paul Jr. calculated the correct chemistry for the metal
based on the required section thickness, the cooling rate of
the casting, and the desired tensile strength of 40,000 psi.
To increase the strength of the gray iron, alloys were added:
chromium, copper, nickel, and molybdenum. In the photo on the
left, Paul Huffman Sr. is standing to the right of the mold,
while the metal is heating up inside an induction furnace. |
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