Thin Section Lab

Susan Boehm

Summary

6 thin section requests, all small format. 4 highly altered and brittle material with a crust, and 1 less altered harder piece from a large drop stone.

Cleaned and refurbished both bottle dispensers.

LP-50

Used for frosting slides and practice thin sections. No problems.

Petrothin

Working. No problems maintaining a strong vacuum. Some water still gets into the black tubing but not so much that there was a need to drain the VS2 water trap. Blade and grinding wheel still in good shape.

Samples and methods

The pieces were very thin and the scientists wanted the section on the cross section to be able to see all outer and inner layers. I used the petro thin and grinding wheel before polishing the rest of the way by hand on a glass plate. Because of the odd shapes, I could not use the hot plate with the clamps pressing down on the sample. The billets adhered reasonably well, I did have some flaking at the end of hand polishing. If there was a way we could apply pressure to oddly shaped pieces I think that would help them adhere better.
Scientists preferred to adhere glass cover slips with NOA adhesive after I was done with the thin sections.

PM5 Polisher.

Used for training and practice thin sections. No problems. I refilled the drum about 1/3 with extra glycol but did not add more diamond powder because it looks like there is still plenty inside.

Miscellaneous

I emptied both bottle dispensers and rinsed and soaked all parts with water. This should be done more regularly to avoid crystallization and blockages. One of the dispensers wouldn't work when I put it back together and I eventually replaced the valve and dispensing tip with a spare from the chem lab and it worked fine. The valve, when in the dispensing position, did not maintain and proper seal and allow fluid to be drawn up.
I opened brand new, non-expired epoxy bottles. Instead of pouring them into the bottle dispensers I kept them in the original containers and used an adjustable pipettor from the chemistry lab to take out the right amounts for mixing. Perhaps keeping the two liquid parts closed tightly in their own containers instead of the bottle dispensers will keep it fresher without any crystallization when large amounts are not needed frequently.
We have six currently expired bottles of epoxy, and the six newest ones will expire in October 2019.