Reviving/re-polishing standard block

[dawncruth]

Hi all,
I've seen this elsewhere but it has been years since others posted to those topics. I'm reviving it here.

I'm planning on repolishing/recoating my standard blocks in preparation for the install of our new probe. Our standard blocks are brass plugs with individual tiny brass rings holding each standard. Any tips of polishing this type of mount, taking into account the fact the wide variety of material hardness?


Thanks for the advice!

Dawn

[Anette von der Handt]

Hi Dawn,

it sounds that you can take the individual standards out, can you polish them individually? Otherwise, my best results come from
1) using low nap polishing pads or even better diamond lapping films,
2) not overpolishing. I rather move to the next lower grade after a few minutes and then go back to the previous step if needed.
3) moving down the grades in steps of "3" (like 9, 3, and 1 micron) and
4) my super-duper trick: finishing step with 1 micron and below with diamond paste on an manila envelope (yes, the ones from the mailroom). Often, many standards look still pretty bad after the 3 micron step and this step just makes them look great after 1 minute of polishing. Never got the same results with 1 micron diamond film or using a polishing pad and diamond suspension.

Otherwise, make sure if any of the standards can't handle water or so. I fell into that trap when re-polishing my Mg-metal. It really did not take kindly to being rinsed off.....

[dawncruth]

Hi Dawn,

it sounds that you can take the individual standards out, can you polish them individually? Otherwise, my best results come from
1) using low nap polishing pads or even better diamond lapping films,
2) not overpolishing. I rather move to the next lower grade after a few minutes and then go back to the previous step if needed.
3) moving down the grades in steps of "3" (like 9, 3, and 1 micron) and
4) my super-duper trick: finishing step with 1 micron and below with diamond paste on an manila envelope (yes, the ones from the mailroom). Often, many standards look still pretty bad after the 3 micron step and this step just makes them look great after 1 minute of polishing. Never got the same results with 1 micron diamond film or using a polishing pad and diamond suspension.

Otherwise, make sure if any of the standards can't handle water or so. I fell into that trap when re-polishing my Mg-metal. It really did not take kindly to being rinsed off.....

Yeah, I think the plugs can be removed individually. I was trying to avoid that, but it seems I'll be legit and complete each, one by one. Would you recommend going up to 9 micron though? My thought was to go max 3 micron and increment down to 0.5 micron.
I think your super duper trick is super duper awesome!

[Probeman]

I started with these brass standard inserts in a brass mount at UC Berkeley many years ago, but because of the hassle in repolishing these standards (we were doing lots of material science and the metal standards oxidized pretty quickly), we soon devised a mounting method using an epoxy-acrylic mount as described here:

https://probesoftware.com/smf/index.php?topic=172.msg8991#msg8991

Much easier to re-polish, clean and re-coat.

The only real downside to mounting 35 or so standards in a single acrylic mount with epoxy, is if you only have a "fly-spec" or two for some standards. Then trying to intersect all the standards at once after they are first mounted in epoxy is difficult and you might lose the material.

One alternative for those standards for which you have very little material is to fill all the holes with epoxy, add those standards for which you have lots of material from the bottom side (let them sink to the top side by poking at them with a tiny wire), then let the epoxy set up, then grind it flat to expose the standards with lots of material, then using a tiny drill bit, drill a small hole on the top side a little smaller than the grain, and mount with a tiny drop of epoxy those "fly-specks" of material, set up the epoxy and carefully polish to expose them.