[meteorite-list] Wanted: A thin section grinding machine Also wanted: Info about your machine / methods

From: Pat Brown <scientificlifestyle_at_meteoritecentral.com>
Date: Mon, 17 Jan 2011 21:39:53 -0800
Message-ID: <BLU117-W27153871EF06323C643AE2BDF70_at_phx.gbl>

Hello Thin Section Fans,

After making a few thin sections by hand, I am in the market for a thin section grinding machine.

***** This is strictly for hobby use for my own entertainment, not a commercial venture. *****

What machine or technique do you use? What do you like or dislike about your machine and/or other tools.

Where do you purchase petrological size glass slides? Among the 'standard' sizes, which one do you use?

What epoxy or other glue do you use?

Do you 'frost' the slide as some of the instructions on the web specify? Is this for epoxy adhesion and does it interfere with the viewing of the thin section?

What motion do you use when lapping by hand? This video shows a straight line back and forth motion on a spinning lap: http://www.youtube.com/watch?v=KzZWZdLb6lA

How do you deal with the tendency of the chip to stick to the lap when using the finer abrasives on the lap?

I am currently practicing on some mid-grade UNWAs purchased last year at Tucson. I will not be attending the Tucson show this year (work is interfering with my life too much, and no, I am not independently wealthy) .

I have an Ameritool 4"/5" trim saw that I use to cut the 'chip' and I am using "EasyCast" epoxy from Tap Plastics. Tap Plastic sells polyethylene molds that are 1.35" x 2" x 1" deep. For mold release, I am using a very minute layer of furniture type paste wax. I have used these molds to embed the 'chip' in epoxy. One face is lapped flat using a combination of the Ameritool 8" lap and a Buehler Ecomet III variable speed 8" lap. The flat side is glued to a glass slide (I am using a regular 1 x 3" microscope slide cut down to 1 x 2"). The rest of the meteorite is cut off free hand. The meteorite material on the slide is then ground and lapped down to something close to 30 microns. The margin between a slide that is thin enough to be usable and having the whole thing disappear is small when lapping completely by hand, so it is time for a thin section grinding machine. My formal education is in electronic engineering, however my work for the last 10-11 years has a large mechanical engineering content.?

The polarizing microscope collection here includes
* Olympus BH trinocular with the 165mm round stage and mostly S Plan objectives including an S Plan FL2 that I love using
* Lomo Polam P211
* Zeiss Standard with round stage and a set of dedicated centering strain free objectives
* Olympus KHC with home-made polarizers
* AO Junior Polarizing Microscope Model 45 with the smallest rotating round stage in the original covered plywood carry case
* Tucsen 9.1MP camera with Zeiss software (free version)
* Various wave plates quarter, half and full wave, De Senarmont, Nakamura half shadow and a quartz wedge

Thank you in advance for any information you can share with me. An off-list response is preferred.

Best? Regards,
??????????? Pat Brown




The Buehler Petrothin looks like a nice tool.


                                               
Received on Tue 18 Jan 2011 12:39:53 AM PST