Reply by TheWoodenOyster

For grit, go with the lowest available, 60 or 80, whatever they have. If you are looking for a bargain, go to harbor freight. Their grinders works just fine and are cheeeeep, as are the sanding discs. Also, make sure you wear a respirator down there while you are working. That galvanizing spray is no good for the lungs. Welders have died from breathing that stuff in too much, so heed the warning on the can. Good Luck!

-- The Wood Is Your Oyster