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8
Handling ZCC 2087.5 and ZCC 2087.6 acc. to ASTM D3359
Hold the cross-cut tester only at the handle.
The flexible cutting head should always move freely.
Never use your other hand or finger of the leading hand to add additional
pressure to the cutting head during testing.
Always pull the cross-cut tester, never push it.
Place the test panel on a firm base.
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Successively make two cuts about 20 mm (0.79 in.) long, the second cut
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crossing the first one at 90°, generating a lattice pattern. Cut through the film
to the substrate in one steady motion using just sufficient pressure on the
cutting tool to have the cutting edge reach the substrate. (For coatings having
a dry film thickness up to and including 50 μm (2 mils) – eleven cuts, for
coatings having a dry film thickness between 50 μm (2 mils) and 125 μm (5
mils) – six cuts).
Brush the film lightly with a soft brush or tissue to remove any detached
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flakes or ribbons of coatings.
Remove two complete laps of tape and discard.
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Remove an additional length at a steady (that is not jerked) rate and cut a
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piece about 75 mm (2.95 in.) long.
Place the center of the tape over the grid and in the area of grid smooth into
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place by a finger.
To ensure good contact with the film rub the tape firmly with the eraser on the
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end of a pencil.
Within 90 ± 30 s of application, remove the tape by seizing the free end and
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rapidly (not jerked) back upon itself at as close to an angle of 180° as possible.
Inspect the grid area for removal of coating using a magnifier and rate the
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adhesion in accordance with the cross-cut scale.
Repeat the test in two other locations on each test panel.
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Issue a test report.
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Page 15
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