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I am at a deficit for making petrographic thin sections not having a lab in which to prepare them. I had planned to test this following procedure but have not found time to do it.
I would appreciate that if someone reading this does test it if they would inform us as to any modifications or problem areas.
1) mount the rock chip on a glass slide using epoxy cement and allow to cure.
2) using a Dremel/moto tool and a cylindrical diamond embedded grinding bit pass the mounted chip below the grinding bit (probably requires reversing the chip at least once) so that the side of the cylindrical bit grinds down the chip. This should require some sort of jig probably made from plastic to hold the glass slide and in the elaborate mode a string and weight to move the chip beneath the grinding bit.
Note that if the chip is reversed the height above the grinding bit is not changed so that the chip has a very flat surface.
3) using the cement of preference (epoxy or whatever) mount the freshly ground face of the chip to a new glass slide. Create a super smooth surface first though by grinding on a glass with some appropriate grit. Removal of the first glass slide may require breaking it.
4) using the same apparatus to hold the moto tool replace the grinding bit with a diamond saw. Note that the specimen will be mounted perpendicular to the previous manner, i.e. in the vertical plane. Here is the questionable area. Some diamond saws do not have diamonds mounted on the edge. This may turn out to be OK as when the wheel is ground down by the rock it will encounter the diamonds. I have been told these saw will cut rock, tile, and glass. These saws also have holes between the axis of rotation an the cutting edge for cooling. Application of a burring compound or oil (making problems for protecting the moto tool) should make cutting more efficient.
Here too reversing the specimen may be necessary (the largest saw I have found is 1-1/2" diameter) in order to cut through the chip's width.
6) Remove the saw and reinsert the diamond grinding bit. Also return the slide to the horizontal position. In this manner run the now slimmed down rock chip left on the slide beneath the grinding bit (reversing when necessary) gradually lowering the bit or raising the glass slide. Do this until just before the bit would start picking out pieces of the thin section from the glass slide.

This should leave just enough of a thin section to be ground on a glass with grinding grit until the appropriate thickness is achieved.

In the foregoing I had envisioned using pieces of thin (1/16") Plexiglas to surround the glass slide and 2 more to be glued (CA gel) at one end and sprung so as to apply pressure to the ends of the slide to hold it down during the process. Such a holder could be moved past the moto tool via a string attached to a weight and kept in place by a simple track made from Plexiglas strips. This whole apparatus could be built using super-glue of gel variety.

Thanks for any feedback

I'd walk around a large 'home improvement/do it yourself' super store, like:"HomeDepot", or "Lowes"...in the title section first, then the gritt-stone/marbel cutting polsh compound section nexst, the the drill bitt, sander section nexst, last the copper tubeing section, metal HIGH TEMP cement last..place my rock specimen (sledge hammer to size of rock which fits a little loose in 4cm copper or any maleable metal tubeing(not steel!). At home place your specimen 'face oriented as you decide the plane to thin across that specimen'...place your specimen inside the tube just flush with openning...vise crimp that softmetal tube hard to hold your sample rock.
The load that tube with high temperature metal cement about that rock, let it cure.
Hacksaw off the length of tube with say 4cm tube beyond inner end of rock sample...fil in empty tube with pebbles/metalcement mattrix..something strong..let it cure.
Now you have a work piece to hold in vise (powerfully hold that specimen it the vise! Grind away under constant spray of water with ceramic diamond cmpd last.
Trick is when to stop gringing, remove specimen in its houseing mattrix...pick it free of metal cement mattrix, cement flat side down..to final diamond grinding on glass plate or whatever high temp holder you use! charlie guevara NJ,US

Based on my experience with using laboratory diamond saws, grinders, and other laboratory equipment and relying on what I was told about the small diamond edged saws and grinders ability to cut rock, the method I outlined should work without a need to use the bonding agents which you described. The purpose in the sequence described is to quickly prepare thin sections especially when one does not have access to lab saws, vises, etc. If I follow your approach it would be like going back to mounting the specimen in a vise, cutting a chip (1/8") off, mounting on glass, cutting it again, and then hand grinding it down. UGH! I don't have such patience.
Perhaps I was not clear in my description. The objective is to get a fairly smooth surface, mount that surface to the slide, cut/grind a good really smooth surface (using rotary motor), mount final glass there, cut to remove old glass and grind to near final thickness so final hand grinding can begin. I made a jig to hold the slides for the process. Hope this is clearer, probably muddied it worse, so will apologize now.
Have fun with it.

One way or another, you are going to need to get a perfectly flat (probably via lapping) CHIP to glue (epoxy or Canada balsam) to a (frosted via lapping) glass slide. One of the easiest ways to do this is to go to an automotive parts-house and buy some WET-OR-DRI sand papers in assorted grits; a sequence of 80, 120, 240, 480, 600, 1200 would be satisfactory. Then using 80 grit paper and either a flat glass or formica countertop, and a dribble or so of water, grind the surface flat and carry on up through each successively finer grit (with carefull CLEANING of glass plate and specimen after each grit size).

Then FROST a slide (600 grit) and epoxy (or use Canada balsam) to affix the chip to the slide.

After the chip is mounted on the slide, thinning the chip might be accomplished using the Dremel tool, but I would think would be easier done by using a diamond cut-off blade. There have been several on ebay lately, some (4") which might fit a hand-held grinder. The specimen might be damaged by overheating if a coolant is not used. I would reccomend a "CONTINUOUS RIM" type blade rather than a segmented blade (less vibration, chatter, and chance of destroying chip/slide).
The best bet might be to invest in a (used) wet-tile saw. Some pawn-shops have them for not very much. Some have been on ebay recently at around $30.oo with shipping. Coolant is very important for preventing heat-spalling effects as well as aiding diamond-blade cutting efficiency.

I really think the Dremel tool concept has some serious drawbacks - not the least is trouble that will be caused trying to get the tool to create a planar surface without a jig or holder; but the problems with cooling, dust, and mess that might occur. It WOULD be nice from a portability standpoint - but if that is a prime requirement, a unit called a "DIAMOND - DEMON" was available that could mount a diamond cut-off blade on one side, agrinding wheel and diamon flat-lap (or polishing pad) on the other. This unit was approx. one cubic foot in size, had a variable-speed drive, and a built-in coolant recirculating pump.

Anyway, once the chip-on-slide is reduced to about 0.5 mm, the rest of the process can be carried out easily on a piece of flat glass with various carborundum grits or with the waterproo0f sandpapers. At least that was the way we prepared thin-sections "back-in-the-day" when I went to petrography class.

Proper thickness of the finished thin-section should be 0.03mm. The proper thickness may be verified by observing Quartz under crossed-polarizers through the microscope - Quartz exhibits "first-order" colors of very, very pale 'faint-straw yellow' to very light (nearly colorless) yellow at 0.035mm thickness. See a textbook of petrology or check out:

Optical Mineralogy and Petrography

Final preparation will require either: a) a cemented-on coverslip or b) a final polishing using something like rouge then either levigated alumina or Cerium oxide (both available at Lapidary supply outfits).

A Lapidary supply outlet might have used machines or they might be able to get you in touch with someone who might have equipment to use.

In addition, classes in jewelry making/lapidary might have equipmnet available. Or check at a local college or university.


Good luck!

All of your points are well taken.
My circumstances do not (and as well may be for others) allow for keeping wet lab equipment in the apartment. I do not like the results obtained by even high end labs in the past. Lastly many do not want to make a major investment in equipment, hence the approach suggested for one off slides. Also my experience with a wet lab is that the stuff eventually stinks.

As you are probably aware, a dremel-like device can be run at a slow or very fast speed depending on the specimen. This seems to be useful in preventing picking.
At this time I am satisfied with the initial "flat" cut which is to be mounted on a slide. The final cutter used is a cylindrical rod with impregnated diamonds. I believe at this moment that it will be satisfactory and was not damaged by the "picking" you mention. This still remains to be certain as it was not examined by other than my 10x lens. Aside from this point I still think the roto-tool (in deference to Dremel) can bring the chip to less than a mm with some care of course. And thus be of use for my one-offs. BTW the saws which I have are continuous edge. I hope their thickness will not lead to diamonds being lost and being one off themselves. That may depend on how much pressure is exerted on the saw by the specimen being drawn thru by a weight over a pulley.

Apparently, I was not clear that I was using a jig to hold the slide relative to the roto-tool and the device sets nicely on my kitchen counter within a plastic enclosure to prevent dust etc. Yes the final grinding must be done on a flat glass plate.

I should like to set up an experiment to run the glass below the slides and use a computer program to monitor the transparency to adjust the amount of grit to apply. That may get too messy for me.

I wish I had time to finish this experiment but my efforts are on finishing some geophysical measurement devices.