Bosch GTR Professional 550 Notice Originale page 10

10 | English
Excessively increasing the contact pressure will not lead to
increased sanding performance, rather it will cause more
severe wear of the power tool and of the sanding sheet.
Do not use a sanding sheet for other materials after it has
been used to work on metal.
Use only original Bosch-sanding accessories.
Sanding Close to Edges (see figures E–F)
Thanks to the removable brush segment, you can reduce the
lateral distance between the wall/ceiling and the sanding
pad.
– Press and hold the locking mechanism (12) for the brush
segment (17).
– Swivel the brush segment (17) forwards and remove it.
– To insert, hook the brush segment (17) onto the oppos-
ite side of the locking mechanism (12), and swivel it to-
wards the sanding head (11) until it clicks into place.
Adjusting the Internal/External Airflow
Depending on the vacuum pressure, the perceived tool
weight can be reduced.
You can switch between different air flow operating modes
depending on the intended use. Turn the suction power ad-
justing lever (13) to one of the 3 positions.
Switch position Type of airflow
① External airflow Ideal for sanding
② Mixed external
and internal air-
flow
③ Mixed external
and internal air-
flow
Adjusting suction power
You can adjust the suction power to achieve your preferred
balance between sanding speed and suction power. This
regulation is only possible when the internal airflow is activ-
ated (position ③ in the table above).
Use the thumbwheel (1) to adjust the suction power.
– 1: Low suction power
– 6: High suction power
Start with a low suction power (position 1) and increase
slowly, until there is a noticeable contact pressure.
1 609 92A 6A8 | (08.05.2021)
High suction power allows low-fatigue sanding of ceilings
and walls. An excessively high suction power can cause the
power tool to vibrate, which can make handling more diffi-
cult.
Errors – Causes and Corrective Measures
Cause
The drywall sander does not run smoothly or jolts across
the surface.
The suction effect is too
strong.
The bodyfiller material and/
or substrates are hard.
The removal rate of the material to be machined is too
high.
The drywall sander's speed is
too high.
The suction effect on the dry-
wall sander is too strong.
Use
The bodyfiller material has a
high proportion of filler or is
walls at high sand-
very soft.
ing speeds and
without vacuum
pressure
The grit of the abrasive is too
coarse.
Medium sanding
The surface quality is not optimal.
performance with
vacuum pressure
The grit of the abrasive is too
effect
coarse.
The drying times for the
bodyfiller material have not
been observed.
Ideal for sanding
ceilings at low
The suction effect is too
sanding speeds
strong.
but with high va-
The bodyfiller material has a
cuum pressure
high proportion of filler or is
(suction power)
very soft.
for a low perceived
The running power tool has
weight
been positioned on the sur-
face (scoring).
There are sanding marks on the surface.
The hard sanding pad has
been positioned at an angle
on the surface.
In the case of very soft body-
filler material, the sanding
Corrective measure
Reduce the suction power or
switch to external dust ex-
traction, if necessary.
Reduce the suction power or
switch to external dust ex-
traction, if necessary.
Reduce the speed.
Reduce the speed.
Reduce the suction effect or
switch to external dust ex-
traction.
Switch on the external dust
extraction, set the suction
power thumbwheel to setting
6 and, in extreme cases, re-
duce the speed.
Use a sanding sheet with a
finer grit.
Use a sanding sheet with a
finer grit.
Refer to the technical inform-
ation sheets and manufac-
turer's recommendations.
Reduce the suction power.
Use a sanding sheet with a
finer grit.
Position the power tool be-
fore switching it on.
Work on the surface and al-
ways work with the remov-
able brush segment.
Use a soft sanding pad with
an intermediate plate.
Use a soft sanding pad with
an intermediate plate.
Bosch Power Tools