Bosch GWS10-450 Operating/Safety Instructions Manual page 22

Sanding Operations
SELECTING SANDING DISC
Sanding discs are made of extremely hard
and sharp aluminum oxide grits, phenol-
resin bonded to a sturdy fiber backing for
fast heavy-duty service and long life. The
discs vary as to size and spacing of the
abrasive grits. OPEN COAT (type H) — used
for soft materials and on paint or varnish.
CLOSED COAT (type K) —used for metal,
hardwood, stone, marble and other
materials.
Sanding discs range in grit from 16 (very
coarse) to 180 (very fine). To obtain best
results, select sanding discs carefully. Many
jobs require the use of several grit sizes and
at times both "open coat and closed coat"
discs are required to get the job done
faster. See chart for application examples.
Operation: Refinishing painted wood or metal surfaces.
REMARKS
To remove paint and to smooth
surface irregularities.
To smooth the rough sanding.
To remove scratches left by previous
discs.
To smooth surfaces for painting,
polishing or waxing.
Sanding Tips
For best results, tilt the Disc Sander at a
10° to 15° angle while sanding so that only
about 1" of the surface around the edge of
the disc contacts the work (Fig. 20).
FIG. 20
edge of the disc comes in contact with the
work, a violent thrust to the side may
result.
If sander is tilted too much, sanding action
will be too great and a rough cut surface or
gouging and snagging will result.
Operating Instructions
GRIT
Coarse
16-24-30
Medium
36-50-80
100-120
Very Fine
150-180
If the disc (accessory) is
held flat or the back
Guide the Disc Sander with crosswise
strokes. Be careful not to hold the sander in
one spot too long. Do not use a circular
motion, as this makes swirl marks. Test
before use on scrap stock.
Do not force or apply pressure when
sanding. Use only the weight of the tool for
pressure. Excess pressure actually slows
the tool down. If faster stock removal is
desired, change to a coarser grit disc.
Remove gummy paint from metal with an
"open coat" disc. Sand until sparks start to
appear, then stop and change to a "closed
coat" disc to remove any remaining paint.
Sanding Wood
When sanding wood the direction of the
disc motion at the contact point should
parallel the grain as much as possible. The
rapid cut of discs and the swirl type scratch
pattern they occasionally create generally
prohibit their use for producing the final
finish.
Scratches and circular marks are usually the
result of using too coarse a grit. When
changing to a finer grit, move across the
sand ing lines that were made by a previous
coarser disc.
Fine
Sanding Metal
When sanding automobiles or appliances,
wipe the metal clean with a non-flammable
solvent or commercial cleaner to remove all
wax and grease. By doing this first, the
sanding discs will sand better and last
longer.
For heavy duty work, use a coarse grit disc
first. Follow-up with a medium grit to
remove scratches. To produce smooth
finish, use fine grit disc.
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