Lab & Things

Quiet has returned to the VP lab as renovations have slowed down here at OSU-CHS. Right now we are waiting for the electrical work to be done before things can move forward with the rest of the renovation. Dr. Smith and the guys from physical plant are sill hopeful that the fume hood can be made to work, but so far nothing definite has come out of the endeavor. So far, we have seen two doors come down (one of which was replaced), creating a much more open hallway; two work stations and an entire wall of upper and lower cabinets have been relocated; the tall cabinet that stores all of our screen washing concentrate was also relocated into the new lab space; one sink was removed and another was re-plumbed; and two rows of "chemistry"-style student benches were removed to make way for new tables. We still have a long way to go, but for now the sound of drills and hammers has subsided.

In Dr. Weil's lab we've begun our microvertebrate molding and casting. I'm still tweaking our set-up and procedure to make the process as streamlined as possible. I have been training some of our volunteers and one of the graduate students on the method, and even though it has been a little rocky in the instruction as we are just beginning the whole process in the lab, our first batch came out quite nicely. Batch #1 had no air bubbles in the tooth crowns, excellent morphological fidelity at low powered magnification, and no unsealed areas with rubber penetration. I am very proud of us. We do need to work on the finer points of numbering/lettering, speed, footer size, and general appearance, but that will improve as we move through more batches.

We patterned our methodology after that of the VP prep lab at the Sam Noble Museum. Kyle Davies (Sam Noble Museum Preparator) graciously trained myself and one of our volunteers on the method. Right now we're using small mammal teeth from owl pellets as our practice specimens. Because these teeth have passed through the digestive track of an owl, they have a higher porosity. Each tooth was sealed in a thin mixture of Butvar-76 and acetone prior to molding and casting. Once we get things perfected we will move onto the actual horde of fossil specimens that we need to mold and cast for SEM imaging. The quality of these casts is so detailed that you can perform SEM micro-wear analyses on teeth as small as a couple of millimeters. By casting, you also don't have to sputter coat original specimens in gold to run them through an SEM, which makes conservators and collections managers very happy. I highly recommend the process.

Below is a brief list of the equipment needed to start a micro-vertebrate molding/casting operation:
 
Centrifuge with swing out trays
Vacuum pump & chamber
Van Aken clay
Rolling Pins
Spatulas of various sizes
Probes
Butvar-79 & acetone
Polyurethane casting resin (we use TC-892 A & B from BJB industries), Anti-foam, & pigment
Platinum Cured Silicone Rubber (we use GT-5092 & CA-5275 from GT Products)
Butcher paper & waxed paper
Needle-nosed pliers
X-acto knife
Clear 16 oz. plastic cups
Unwaxed 4 oz. paper cups
Cardboard working trays
Gloves
Vials for "cookie cutting" clay

~JB McHugh

Teeth set up in clay waiting for molding compound.

Our centrifuge.