Bruce, I've organized group buys on abranet for the IAP members 3 times, with the most recent being Dec '08, delivery in Jan '09. While there are a variety of grits available in a variety of formats (Sheets, rolls, disks), I've generally limited the grits to 80, 120, 180, 240, 320, and 400. In the bulk quantities needed to get the discounts, these seemed to cover the largest range of requests. The full range of grits (to the best of my knowledge) is 80, 100, 120, 150, 180, 220, 240, 320, 400, 600, 800, and 1000. The supplier I use does not carry all grits in every one of the different sizes of all the formats available (sheets, rolls and disks), though the disk versions seem to have the widest selections in their varying sizes. Since many here use MicroMesh, and micromesh 1500 is roughly equivalant to 400 grit, my experience has been that there is limited demand for the grits above 400. As has been mentioned, one of the positive differentiators has been the open weave of the abranet product. As a result of this feature, the sanding dust has an easy path for escape, so abranet rarely clogs and is easy to clean and re-use. This also results in less heat build-up, and I believe it also assists in reducing color contamination when using segmented woods, though it is not a cure for that issue. I use the 80 grit for a lot of work on tru-stone blanks. One of the things you can't use abranet for, is when trying to use a slurry of sanding dust and thin CA to fill open pores or voids on blanks, so I always keep a supply of 120 grit regular sandpaper cut into 3/4" by 5 1/2" strips handy. While abranet lasts significantly longer than regular sandpaper, it does wear down and lose it's "bite" over time. This has seemed to take place more quickly with 400 grit in my experience than with the lower grits. I go through more of the 320 grit than any of the others- largely because it's the grit I primarily use after applying my rough coats of medium CA to level out the finish followed by a quick hit with 400, before switching to wet sanding with the 1500 micromesh up through 12000. I cut my strips into roughly 1 1/4" wide by 2 3/4" long pieces, and use a black sharpie on the fuzzy backing material to keep track of the grits- using a "1" for 120, a "2" for 180, a "3" for 240, and a "4" for the 320. the 80 and 400 grit are visibly different enough that I don't need to mark them in order to correctly identify their grit. The orientation of the strands in the abranet weave is such that it sands, or "cuts", more aggresively if oriented such that the top weave is parallel to the blank, and cuts less agressively as you rotate the orientation of the abranet. By cutting my strips to the smaller size, not only do I get more usage out of each piece (you tend to use the outer edges of the abranet to sand), but I also have more ability for fine control during the sanding process by rotating the orientation of the weave, and hence the aggressiveness of the cut. Hope this info helps- please let me know if any of this raises additional questions.
