Thursday, September 30, 2010

Calymene Update

This post is an update on a Silurian Period Calymene trilobite fossil I have been preparing.  This first image shows a lot more of the sides of thorax exposed with large chunks of the matrix removed.  The pygidium has been sandblasted mostly clean.  A new tool was used to remove large sections of surrounding matrix.  A Dremel tool with a circular cutting disc attached made short work of the shale matrix.  Looking at the picture the left side displays evidence of a cut line.

The picture above shows the trilobite at head level with more of the lower thorax showing.  A Dremel engraver was used to accelerate removal of this material to complement the engraving needle.  The engraver is a somewhat risky tool to use as the fossil could shatter or start to crack.  For the most part used successfully, a crack has appeared under the center of the cephalon right above the matrix.  Looks like I will need to super glue it to stabilize that section.

 Overhead view of the trilobite after it has dried.  Notice the cut lines from along its outer borders.
 Close up view of the pygidium and left side thorax lobe.  Part of the side thorax chipped off when the matrix was being cut.  It was super glued back on.  Also a small thorax ridge segment broke off when the needle tool was being used earlier and it was super glued back on.  The sand blaster seems to have removed evidence of excess glue around those parts.

View of trilobite's right side with the matrix under the cheek and eye removed.

Thanks to Kenny for letting me use the sandblaster and with the idea of using a Dremel cutter.  Also suggesting I start using the engraver more to help remove the large amounts of matrix around the front of the cephalon.  It uncovered a pyrite ball on the left side that took some time to break out!