Important Notes on Sanding! Back to Sanding .......
On the sanding, what is firm pressure? Place your hand down on a bathroom scale to get a feel for 10 and 15 lbs of downforce. It should stick in your head. 15 lbs for 500 grit and 10 lbs for 1000. Maybe like 5 lbs for 2000 and up.
And most ball spinners rotate clockwise, so you want to do circles counter clockwise starting at the top pole of the ball to the equator. This creates a uniform pattern of grit marks that cross each other. You don’t want all the grit marks going the same direction.
Important Notes on Sanding! Back to Sanding .......
1-Bathroom scales are not that accurate.
2-10 to 15 pounds of pressure, Is
alot of pressure! Lighter pressures cut more efficiently. Also High pressures reduce the life of your pad/paper.
3-The top of the ball sands faster than the sides, So do the side just slightly longer (or the top less) so the amount of sanding is more even.
4-As for which direction your spinner spins, What matters more is what hand you hold your pad/paper in.
If say your spinner goes counter clockwise (Like my tub mount does). Holding your abrasive in your left hand, causes you to lean into the pad because the ball is spinning into the heel of your palm. This tends to produce a higher pressure.
Holding the pad in your right hand the ball is spinning into your fingers and gives you better control of how much pressure your applying.
Ultimately you basically want to use a more even pressure with your entire hand.
5-Wet sanding produces a more sheen like finish, water acts as a lubricant to a point so the cutting isn't as aggressive.
Also wet sanding helps keep the dust and friction heat down, the water also helps reduce buildup of the cuttings in your pad/paper which let's them cut better and last longer.
Wet sanding is pretty much the standard when using a home spinner.
6-Dry sanding is a bit more aggressive and will give you a duller surface. But you get more friction which generates more heat and the pad can load up which can reduce the effectiveness of the cutting. Plus you should wear a dust mask so as not to inhale the dust particles produced.
Comparison of dry & wet sanding (same grit) can be see here:
