I used to use a lot of water when sanding, but I don't anymore. I prefer the reaction of the dry sand process. It took me a while to find the best method for dry sanding, but now that I've got it down, I come closer to the box finish than I ever did with wet sanding.

The downsides of dry sanding:

1. Lot of dust. I wear gloves and a dust mask, but some probably still gets in.
2. Pads wear out more quickly. But I figure at about $2.60 a pad, screw it, I don't resurface that many balls anyway.

The upside of dry sanding:

1. As mentioned above, I like the reaction over a wet sanded ball at the same grit(s)
2. Dry sanding is MUCH faster. It takes about half the time as wet sanding for me.
3. I can see the results of each grit level more clearly, so I get closer to what I want.
4. Compound finishes are much easier to create than with wet sanding. I can make a 500 - 4000 finish almost perfect. I was never able to recreate that kind of surface with wet sanding.
5. I actually think I take less surface off the ball each time. I use less pressure and time than wet sanding seems to need, so I think I take a much thinner layer on each pass than when I was wet sanding.




Disclaimer; your results may vary. 

I use a spray bottle with water and no sink.  I dont go heavy on the water just keep it moist not flooded.

I use water a bit on the heavy side. Pads last longer and it seems to give me the surface I want without overly deep sanding groves in the ball.

When sanding dry, besides all the dust is the fact that with each revolution of the ball your sand paper is loading up and each succeeding revolution is with less grit.  Waters main mission is to keep sandpaper clean so grit remains about the same for awhile.   Even with water, grit will change pretty quick.