Buehler thin section polishing

Thin sections, 1 in the center of the holder

  • 3 micron diamond grit: 20 minutes, 20 lbs, 120 rpm, dispenser at 1 or 2.
  • 0.3 micron diamond grit, 10 minutes, 15 lbs, 120 rpm, dispenser at 2.
  • Start section at 5 lbs pressure (minimum). After holder is pressed to the platten, raise pressure to the recommended value.
  • Alternative: 0.3 micron alpha-Al2O3 grit, suspended in deionized water, or Buhler’s grit extending solution. Use 15 lbs pressure for 10 minutes, then 5 lbs for 5 minutes. No, I don’t know why Al2O3 cuts so much faster than the diamond.

Replacement lap surfaces

Lap surfaces should be the Buehler Texmet 2500 non-woven fabric disks. These result in less surface topography than the softer Texmet 1500 or woven fabric surfaces.

Thin section holders

Thin sections should be secured onto the thin section holder with a piece of double stick carpet tape about 1/4″ by 3/4″ (6 by 20 mm), with the tape centered on the rock area rather than the glass.

This is a photo of the back of a Buehler flat, blank sample holder. As-is, it can’t hold any samples, but see below. The Buehler part number of the whole assembly (black disk plus stainless steel fitting) is 602408. If you have a machine shop, you can make your own disk and just buy the stainless steel fitting, part 602499. Here are plans for the disk.

I’ve tried numerous ways to hold thin sections in the holder. This is the best so far. Cut a circle of adhesive-backed rubber sheeting, 1/16″ thick (about 1.5 mm). Put it on the clean disk bottom, and bevel the edges with a very sharp blade. Cut a thin section-shaped hole through the rubber, with extra space for corners (important). Glue in a spacer (I used a piece of plastic ruler) to make sure the thin section surface extends slightly beyond the rubber surface. The thin section is initially held in place by double-stick tape, as mentioned above. Take the tape into account when choosing a spacer.

Self-adhesive rubber sheet can be obtained from many places. Yes, I’ve tried setups with multiple thin sections, but that always resulted in uneven polish. Let me know if you find something that works better!