I have experienced very good performance with Norton A275 sandpaper. It is very sharp. Stays sharp for a long time. And does not clog. Excellent perfomance on both wood and steel. Norton isn't cheap to buy but I think if you figured cost/sanding time and quality it would be cheap.
And this comes from a guy who grew up in St. Paul with many 3M employees in my neighborhood. I grew up supporting 3M products. I worked in the hardwood furniture industry and did some deep dives in to abrasive performance back in the '80s. Had a chance to spend some time at the 3M test lab learning about their different products and what should be used in different furniture and wood species applications. Maybe 3M or someone else has a product equal to the Norton a275 but I'm not aware of it. That said, I haven't tried the 3M Sandlblaster or Klingspor paper. So I can't compare them. I have used both of their belts on a 2'x72" belt grinder and like them both.
I learned about the Norton a275 when in Trinidad summer gunsmithing classes from guys like Chuck Grace, Dennis Potter and Glenn Fewless. The paper back is stiff enough not to flex too much when just held around a sanding block. If you really want to produce a flat surface then gluing it on to a sanding block with a spray adhesive permits high quality sanded finishes. There are also some rolls of Norton a275 with a adhesive back that I'm starting to use.
Gary
