Porter Cable 503 Manuel D'utilisation page 11

SPECIAL SANDING PROCEDURES
Ordinarily the sanding stroke is back and forth. Some materials and some
types of operations, however, require a different technique. In rough
sanding, use the machine at an angle. In spot sanding, use the machine
with only the front pulley touching the surface (especially required in
smoothing excess glue from wood joints). Metals, slate, marble, and
plastic materials have no grain. Therefore, the sanding on these worpieces
may be done in different directions.
DOORS AND MILL WORK
When sanding doors, cabinet frames, sash, storm windows and screens,
avoid working into the cross grain where one member meets another.
Notice that the right edge of the belt is visible on your sander. Watch it
closely. Work carefully along the edge where the rail meets the stile. If the
joint is slightly uneven, use a fine grit abrasive and very light sanding
pressure, smoothing the joint prior to making the finishing runs.
GOOD SANDING TECHNIQUE
Getting the feel of the sander is important in obtaining smooth results
with minimal labor. Experience will teach the operator how to start the
stroke with a sweeping motion that will produce the best results. Use
long even strokes with little pressure on the machine.
Overlap each stroke and vary the length of movement so that the results
will be even over the entire surface. Always lift the sander from the work
before starting and stopping the motor. If the machine drops, it will
round the edge. Keep the sander flat on the work surface (Fig 6). Avoid
letting the machine drop as it gets to the end of a workpiece. (Fig.
7). The sander will work well if these suggestions are followed. The
machine works very fast and can do a thorough job in a fraction of the
time required by hand sanding. Do not rush the job. Give every surface a
thorough sanding with each grade of abrasive before changing to finer
grits. Always use the abrasive material and grit size recommended for
the job.
Fig. 7
Fig. 6
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