[mpierich]

I wouldn't go down to 80-grit...it might be fast but it'll leave beaucoups scratches to get out. I always start with 120, even on sand-cast parts.

Wet sanding might help a little when you get to 220 or above. The soap thing is sort of overkill...it's used when wet-sanding paint finishes... but it can't hurt, just a few drops per gallon of water is plenty. Wet sanding will definitely make your sandpaper last longer. You don't say how you're doing the sanding (by hand?) but you might want to try greaseless compound in 120/220/320 grits.

The cleaning between grits and compounds is very important. When you get to the polishing compounds, brake cleaner, lacquer thinner or acetone (etc.) is needed to get all the grease off.

As far as your results, I would say that the biggest flaw in your ointment is the drill speed. You need to build up heat for the compounds to work right. Also, even a Ryobi will burn out with continuous use. If you can, maybe get a cheap drill with a higher speed. Some folks on here use high-speed angle grinders with buffing wheels, but in my opinion that's a little dangerous since most wheels aren't rated for that 20,000 - 35,000 rpm speed.