I repaired my cracked fairings with some plastic weld that Autozone sells. The stuff is great. Anyways, I don't know what grit to use in order to sand it down and smooth it out. Do I need to wet sand it?

 

I'd use 180 or 220 to smooth it all out. Then 400 to take out the sanding scratches. Then 400 wet, then wet sand with an "ultra fine" scrubby pad. Now clean it real good with some rubbing alcohol/water mix. (much cheaper then prep cleaner) (and dont touch it once its clean, your oily finger prints may f* up the paint job). Now yer ready for paint. Make sure you use adhesion promoter. Spray paint might look good....for a minute. Use auto paint that is designed for ABS.

 

How many parts of each do I use in the alcohol/water mix?

 

20-30% alcohol. Accuracy is not important, its not like mixing paint. Just add enough water so that one bottle of rubbing alcohol will finish the job. You can use the mix when wet sanding with the scrubby too.