Ray
This is turning into Corian 101, but the top manufacturer should have had some instructions and Scotch-Brite pads included in the fifth wheel owners packet. No, the micron rated paper is a specialty item that should be available from anyplace that fabricates solid surface tops (3M Imperial #366L-100 micron down to 50 micron;3M Trizact #735U-35 micron down to 00 micron). Depending on the fabricator, sometimes they consider down to 35 micron a matte finish (wet sanded). It would be difficult to do w/o a random orbit sander unless it is a small area. I have even had to go down to 10m dry or wet sanded - can't remember now - to match a scratch repair in a "matte" gloss level. Home centers, etc, carry only the common items. The special abrasive paper is used primarily for ss material so it would only be found at the same places that sell the material, and you can't buy the ss material unless you are a certified fabricator. If you can't find it let me know and I'll send you a disc(s). Do not use any other type of abrasive disc on it or it will scratch it. These papers have only 1 size of abrasive embedded, unlike other types that have averaged sizes. If its just a little dull then a 3M Scotch-Brite abrasive pad is all that is needed (3M# 7447 --maroon/360-400 grit, considered matte; or #7448--gray/800-1000 grit, considered semi-gloss). A lot of tops are produced with a semi-gloss finish, which is down to 5m, wet only. It is a little complicated, and materials are expensive ($2-3 per disc, and a typical rv kitchen may use 20-30 discs), so try the Scotch-Brite pads first. Remember, it is easier to dull a finish down if you get it to glossy than to go the opposite way. Let me know if I can help. Discs are color coded for the fabricators: 50-100 micron is a gray disc, 35m is green, 10m is blue, 05m is orange.