Making Molds for Artifact Copies

As part of an archeological dig simulation we wanted to make copies of artifacts found locally and bury the copies in the dig boxes. We wanted to make copies of artifacts ranging over a time period of thousands of years. We were able to borrow copies of artifacts found at the Trochek site that ranged over a 5000 year time period. Our copy method had to leave no trace of the copying process on the artifacts

Forms for the molding process are selected to fit the artifact and has a sung fitting top. Soap dishes or tooth paste holders with long tops are quite suitable for different shapes.

Materials

• form shapes ( soap holders)
• silicon in a tube
• water
• vaseline
• artifacts

Tools

• caulking gun
• stir sticks
• tubs

Enough silicon to fill one side of the form is ejected into a tub. The tub is then filled with water and the silicon is then stirred. The water is replaced and the silicon is stirred again. The water removes the acidic material that keeps the silicon from hardening so the silicon will set up in one to two hours. The forms is filled and leveled. The artifact that is to be copied is covered with a thin film of vaseline. This will allow a later release. The artifact is then pressed half way into the silicon in the form along a symmetrical axis. Let the silicon harden over the next few hours.

Once the silicon on the first half of the mold has become solid (not rigid, since it remains a bit flexible) cover the surface with a thin film of vaseline. Now repeat the process of stirring the silicon in water. Holes need to be drilled in the top part of the mold so that excess silicon can squeeze out when closed. Once the silicon has been well washed, fill the second half of the mold. Close the mold tightly and let the silicon set.

Once the molds have hardened, remove and wipe clean the original artifact. A cavity is left in the forms.

Bondo (the autobody filler) is mixed with the catalyst and put in the cavity. Close the mold and put pressure on the it. The Bondo hardens in about an hour (depending on the temperature and amount of catalyst added). Once the bondo hardens, remove the artifact copy from the mold, trim the excess and let it harden overnight.

Select and mix acrylic paints to match the colour of the original artifacts.

A number of artifacts can be fit in a mold at one time. The image above shows three artifacts copied in one form. Four painted copies of artifacts are shown. These copies are embedded in the simulation dig boxes that are recovered layer by layer.