The 150 grit 1x42 Cubitron belts were discontinued, but it appears they are back in stock here:
https://www.rshughes.com/p/3M-Cubitron-7...111_67951/
If you don't have a clean leather belt use whatever you have on hand. I mean, the idea is that you just don't want to use too much fine abrasive so as to avoid removing tooth. It's possible to use a bit of soap and water and scrub the belt with a brush to remove compound buildup. Once it's dry, use a bit of oil to condition the belt again so it won't crack and is supple again.
The leather belt I'm currently using still has white color from a few years ago. I was making a polished edge so I put some Tormek PA-70 on it. The PA-70 is AO, 1-3 micron and I'm quite sure any remaining abrasive has long since worn out and has very little if any effect. Nonetheless it still has some white discoloring but I just use it and don't worry. It seems to work.
This stuff isn't rocket science. You have a microscope so you can check the edge and see if whatever procedure you are using is smoothing the teeth or not. You just gotta play around and check the results so you understand what's happening. You'll get it.
https://www.rshughes.com/p/3M-Cubitron-7...111_67951/
If you don't have a clean leather belt use whatever you have on hand. I mean, the idea is that you just don't want to use too much fine abrasive so as to avoid removing tooth. It's possible to use a bit of soap and water and scrub the belt with a brush to remove compound buildup. Once it's dry, use a bit of oil to condition the belt again so it won't crack and is supple again.
The leather belt I'm currently using still has white color from a few years ago. I was making a polished edge so I put some Tormek PA-70 on it. The PA-70 is AO, 1-3 micron and I'm quite sure any remaining abrasive has long since worn out and has very little if any effect. Nonetheless it still has some white discoloring but I just use it and don't worry. It seems to work.
This stuff isn't rocket science. You have a microscope so you can check the edge and see if whatever procedure you are using is smoothing the teeth or not. You just gotta play around and check the results so you understand what's happening. You'll get it.