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Making
Stone Tool Replicas
Archaeologists often find artifacts, or objects made
by humans, that are one-of-a-kinds. Unique
artifacts give credit to human creativity, but can make an archaeologist's
job difficult in several ways.
Obviously, it would be hard for an archaeologist to
study a tool if it was in a museum 300 miles away.
And even if the artifact was close-by, the risk of altering or
damaging the artifact may be too great to allow for study. Some private collectors also do not allow studies to be done
because of risk factors. Even
when examination is acceptable, few people would feel comfortable working
with artifacts such as those seen below.
Replica Artifacts
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In cases of rare or fragile artifacts, making
replicas can create several advantages.
Replicas can be examined by archaeologists for select information,
can be more easily displayed and transported, are less likely to be
stolen, and can be used repeatedly in educational classes and activities.
For these reasons, a method for creating replicas of
stone tools has been developed, largely through trial and error.
The technique used by the Mississippi Valley Archaeology Center was
developed with the guidance of Betty Steele.
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The
Process
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The artifact is embedded in clay so that only one side
is exposed. The edges are
carefully worked so that when a cast is made, the two halves of the mold
match perfectly. Once the
artifact is properly embedded, liquid rubber mixed with a hardening
agent is poured on. The artifact itself is not harmed or altered by the mold
materials used.
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The rubber hardens in about 48 hours.
After that time, the clay is broken away, leaving the mold and
stone artifact. Then the
other half of the mold is created following the same steps.
Once complete, the two halves are coated with a lubricant so that
the mold can later be removed without injuring the finished replica, or
cast. |
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With the two halves of the mold ready, the next step is
mixing the plastic resin that will form the replica artifact.
The resin is made from two ingredients.
The Part A and Part B ingredients are mixed together in specified
amounts to make the resin. |
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Part of mixing the resin is choosing the color of the
replica, which can be made to resemble the original artifact or be altered
to better highlight aspects of the artifact or easily distinguish it as a
replica. To do this, color
pigments are added to the resin. |
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The ingredients are mixed together using a
jewelry vibrator. After
mixing, the resin is allowed to sit so that air bubbles can escape. |
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Next, the resin is poured into the two coated halves of the
rubber mold. Soon the resin
begins to thicken and the two mold halves are put together. The edges are sealed with nails and the top is weighted down
for an extra tight seal. |
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An Incomplete Replica
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After about 8 hours the resin has hardened and the mold can
be opened, revealing the cast. The
resulting replica may indicate that the molds were not precise or the
seals were out of alignment. Certain
steps of the process may have to be attempted again. |
The
Finished Product
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Eventually, or perhaps the first time, the end result is a
replica that is exactly what is wanted.
The real artifact can then be returned to safer storage or display
while the replica can be freely used for education, research, and display. |
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Answer: The real point is second from the
left.
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