been thinking of taking the plunge and getting a batt lap. Question for all of you that use them, I know that you cannot move to finer diamond grit for polishing on the same side, but does this also apply to oxides? Say could I use 50 or 100k diamond one day, clean and then use cerium oxide on the same side?
Thanks- Steve
You will never get the diamond out of the Batt lap, so whatever grit you use will always be there. Unless you machine the surface.
Good to know, Thank you!
I agree with as1067. Once you charge a lap, keep it for just that grit or polish alone. Nothing more frustrating that to be putting a super fine polish on a facet of a stone, looking at the stone and AAAARRRRRGGGHHH!!! ##%&@*!!, your once polished facet now has 4 or 5 scratches streaking across the facet…how do they say it in Monopoly…“go back to start, do not pass go”. 
Not only that, but there is nothing worse than a contaminated lap.
I use a BATT charged w 60K that works better than oxide ultra laps most of the time —- but, I have found oxide ultra laps are best when I have those obstinate stones that just don’t like diamond polishing. But I agree, you’ll never get all the diamond out of the BATT once charged.
Good to know, thank you all. Now next question, 50k -60k loose diamond powder or something like a batt stick or other grease based syringe type of polish to use? Also, does anyone ever tend to need a polish finer than 50-60K? I see the powders down to 100 and 200K but I never seem to hear about anyone using those. Any info appreciated!
I use pandemonium 60k. It is like chapstick. I’ve never used anything finer than the 60K. At some point you would only notice a difference would require a microscope. Of course it is also possible that 100K might be required for competition cutting, but I am a long way from that.
I use 50k. Tried 100k, but really didn’t see much difference. Initial charge with paste, then spray afterwards. Clean with WD-40 when it quits polishing. Occasional clean with WD-40 when lap gets dark.
Hi Steve - Sorry I’m a little late joining in the conversation but thought that I would add my own observations all the same. Firstly, I can’t comment specifically on BATT laps as I do not own one but regularly use Typemetal and Pewter alloy laps charged with 50K diamond to polish a large variety of stones - the exception being Quartz which I always polish with high grade Cerium Oxide. When I polish Topaz, I use a combination of the 50K diamond and Linda A (aluminum oxide) on the same lap at the same time and love the results. When I started to facet many years ago, I was told that you cannot combine diamond and oxide polishes on the same lap but this not the case. Without a doubt the 50 K lap will always be a 50K lap but adding oxides is still possible.
My thoughts on the difference between 50K and 100K diamond polishes = I am a competition cutter and regularly get scores in the very high ninety’s and even the odd 100 and you can note see the difference between a stone polished on 100K compared to one polished on 50K under a 10X loop (which is the magnification most competitions are judged with). Get the pre-polish right and 50K works fine - get the pre=polish wrong and not even 100k will save you.