Aluminum oxide is a very hard mineral that maintains sharp points on the grains much longer than natural abrasives such as emery or garnet. The abrasive grains are adhered to the sandpaper with some space between them, known as open-coat construction, to minimize the buildup of dust on the surface of the paper, which would otherwise load the abrasive points. Loading often results from sanding soft materials and can clog the abrasive, shortening the usable life of the sandpaper sheet.
3M 02116, Paper Sheet 346U, 60 D-weight, 9 in x 11 in, 7000120221
$1.11
Factory Stock, 7-10 Day Leadtime
3M Paper Sheet 346U is constructed of aluminum oxide and comes in a range of grades and sizes to accommodate many different projects. The paper backing is durable for coarse sanding, yet flexible enough to be used on curved surfaces. Its cut-rate and durability make this an excellent choice for blending the joints of connecting pieces in wood- and metal-working.

ACS Diamond Cloth Belt, CX1250 3" X 30" 20U
3M 34573, Cubitron II Net Sheet Roll, 120+, 115 mm x 10 m, 7100247507, 6 Rolls/Case
3M 30189, Trizact Hookit Foam Sheets, 5000, 2-3/4 in x 5-1/2 in (70 mm x 140 mm), 7000120137, 5 sheets per carton
3M 19768, Utility Cloth Sheet 314D, 9 in x 11 in P180 J-weight, 7000000356
3M 17227, Heavy Duty Duct Tape DT11, Silver, 48 mm x 54.8 m, 11 mil, 7100158346
3M 22409, Roloc Disc 361F, P120 XF-weight, TR, 1-1/2 in, Die R150S, 7000045103
3M 06742, Overspray Protective Sheeting, 20 ft x 250 ft, 7000120043
3M 34566, Cubitron II Net Sheet Roll, 240+, 70 mm x 10 m, 7100247511, 6 Rolls/Case
3M 22397, Roloc Disc 361F, 60 YF-weight, TR, 1-1/2 in x NH, 7000045097 
