On Sat, 9 Jul 2005 06:33:20 -0700, "Mike Fields"
wrote:

I have a couple of the 4-1/2 inch grinders (which
I love) and was wondering from a cost point of view which people
preferred - the sanding disc or the flapper discs

There are _lots_ of disk types out there. Get a load of them
(especially if your supplier offers bulk prices on mixed lots) and get a
variety - then use what you liked.

In general, buy the best you can. They work better, they last longer,
they work out cheaper long term. If you're using a grinder a lot, then
your disk consumption will be significant and worth getting right.

Personally I use all of them from time to time, but most of all it's the
flap disks. I only still use cutting disks and the hard grinding disks
for working into corners where I need rigidity.

I don't use sanding disks though. An angle grinder is too fast for a
simple flat disk and you get a lot of edge scoring that's work to take
off afterwards. It's also too easy to overheat such a small area of
abrasive. For sanding disks I might use a slower drill and some 3M
non-round disks (rounded triangles) that don't have theis same
edge-scoring problem.

I like the Hermes brand as an abrasive, especially their coated blue
Zirconia. It's particularly good as sanding disks for wood, but it's
good on a flap disk for metal too. They also use a plastic backing,
which is softer if you run it into an edge, either accidentally or to
shave a worn disk smaller. You can shave aluminium-backed disks down too
(if you've only got one 40 grit left in the box and the shops are
closed!) but it's a bit hazardous - it may catch and feed you a faceful
of grinder.

I also like "Flexidisks", which I've only seen from Grayson. These are
flap disks with half the number of flaps and a soft foam spacer between
each one. They're expensive for general use, but they're good for convex
compound curves as they don't wear flats by accident.

It's worth also investigating the extra-thin cutting disks, the
paint-stripper plastic webs and the diamond disks for stone - they all
have their uses at times.