I have dabbled in woodworking a little; so I remember these.
I remember reading the old catalogs when these micro mesh sanding sponges first came out. In it, they said these grit levels, up to 12000 grit were not based on the same numeric system as ours (600, 800, 1000, 1200, 1500, 2000, 4000) are. In fact, If I recall correctly (would have to dig out some 1995-1999 woodworking catalogs out of the basement), even the 12000 is not as fine as our current 4000 grit Abralon pads are.
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Yup, I found it. They said explicitly that the 1500 grit mico-mesh is equivalent to normal sandpaper's 600 grit. I'm not sure which micro-mesh level would be equivalent to our 4000 grit abralon - possibly the 8000 grit. That would leave only the 12000 grit as finer. I'm not sure that is economically feasible.
Great idea, though.
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"None are so blind as those who will not see."