Bosch GWS18V-10 Consignes D'utilisation/De Sécurité page 30

Sanding Operations
(Fig. 22)
Selecting Sanding Disc
Sanding discs are made of extremely hard and
sharp aluminum oxide grits, phenol-resin bond-
ed 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 ma-
terials.
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 paint-
ing, 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. 22
Operating Instructions
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.
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
Grit
motion at the contact point should parallel
Coarse
the grain as much as possible. The rapid cut
16-24-30
of discs and the swirl type scratch pattern they
occasionally create generally prohibit their use
Medium
for producing the final finish.
36-50-80
Scratches and circular marks are usually the re-
Fine
sult of using too coarse a grit. When changing
100-120
to a finer grit, move across the sand ing lines
Very Fine
that were made by a previous coarser disc.
150-180
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.
-30-
If the disc (accessory) is
held flat or the back edge