I can't say enough about how much useful information I have found in
this news group. As I don't like freeloaders, I think I can contribute
something here.

As my nickname suggests, I do a LOT of sanding...and I mean a LOT.
And because I learn so much in this NG about my first love, woodworking,
I am more that happy to share what I have learned about sanding since
the days when solid surface countertops only came in 4 colours. (now 400)

Envision this:
a 4-ft x 6-ft kitchen island top.

Black or very dark colour.

Windows everywhere.

At the point of purchase, the customer signs a waiver.."This is black,
ma'm...it will show everything. Do NOT call me if the electrician drags
his tool-belt all over it."

But, as it is over 30" wide, I need to make a seam during fabrication.
And I get to sand it till the seam disappears.
Then I get to make it shiny..semi gloss. And optically flat.
Only the guys at Mt. Palomar Observatory have a more daunting task when
they polish their mirrors... ok..I embellish..

The most important things to remember,
1) Buy the best you can afford. One can drop a $1000 on a sander/sucker
combo. Fein comes to mind. My current favourite is Festool's Rotex 150
with a CT-22 sucker. Not only does the Rotex suck dirt off the work, it
also blows air in the middle of the pad. See animation under
ProductsanimationRO 150E http://www.festool-usa.com/
The biggest punch for the buck for the non professional, IMHO and a
combo I use all the time, is the Ridgid 6" ROS (Really a Metabo) hooked
up to a good sucker with a 1 micron bag. I use a 4.5 HP (Yea right)
Shopvac with a 10 gallon 1 micron bag (Sold separately, batteries not
included, see you lawyers for details.)
2) make sure it has very good dust removal. See above
3) choose the right paper for the job. I now use, almost exclusively,
Mirka Abrinet. Sure it costs money, but lasts, and lasts and no holes to
align up on any 6" sander. It's a screen. I also make up a lot of my own
pads from Scotch-Brite style hand pads and I glue them on an old sanding
disk. NEVER put ScotchBrite-style pad directly onto your Hook & Loop
(Velcro) sander. The little nibs will wear off quickly.
4) clean..CLEAN.. in between sanding steps. The grit from the previous
paper WILL keep scratching. IOW.. when you go from 180 to 220, the work
is full of 180 size particles...blow it off, wipe it... hell, LICK it.!

I also use a LOT of sanding sponges..fine on one side, medium on the
other. Handy little things, those... CAREFUL when you sand along the
edge of an oak board along the grain. Large splinters can travel up
through the sponge and accordion into your right hand's index finger's
second joint, requiring surgery and enough antibiotics to make a grown
man puke.
Or so I'm told.

Hope this helps.
Rob
www.topworks.ca

PS.. I am not affiliated with Festool, Mirka, Pfizer, Heineken, Chivas,
Bentley Motor Cars, or Meg Ryan.
And the rumour that my Aunt Bee is a lesbian, is just that.... a rumour,
okay??