MIL-DTL-24487B (SH)
shall be tested for a period of 6 hours. At the end of the 6 hour period, mark the end point on the steel where the
rubber is still just attached to the steel. Measure the distance between the starting and end point marks on the steel
and divide by the number of hours over which the test was conducted to determine the inches stripped per hour for
the test specimen. Adhesion shall be the average of the values measured for the three test specimens. Adhesion
shall conform to the requirement in 3.2.
4.5.8 Vibration damping characteristics. Conformance to 3.7 shall be determined by the procedures
described in 4.5.8.1 through 4.5.8.3.
4.5.8.1 Test specimens.
4.5.8.1.1 Test specimens for Class 1 vibration damping treatment. The test specimens for determining
Class 1 vibration damping characteristics shall be as follows:
a. Three flat steel bars, each 0.5 by 3 by 26 inches (1.3 by 7.6 by 66 cm). Each steel bar shall be cleaned with PF-
145HP degreaser, abrasive blasted to SSPC-SP 10, cleaned again with degreaser and allowed to dry.
b. Three flat steel bars, as above, with strips of damping treatment completely covering one 3 by 26 inch (2.6 by 66
cm) face on each bar (bars from 4.5.8.1.1.a. may be used after measurement of bare-bar damping
characteristics).
The damping treatment strips shall be bonded to the steel bars using the bonding procedures detailed in 4.5.8.1.3. A
coat of paint, with a maximum dry film thickness of 3 mils, may be applied to the unbonded surfaces of the steel
bars to protect against corrosion. The assembled test specimens shall be allowed to set at 80 ± 9 °F (27 ± 5 °C) for
at least 96 hours prior to temperature conditioning for the vibration tests.
4.5.8.1.2 Test specimens for Class 2 vibration damping treatment. The test specimens for determining
Class 2 vibration damping characteristics shall be as follows:
a. Three flat steel bars, each 0.625 by 3 by 29 inches (1.6 by 7.6 by 73.7 cm). Each steel bar shall be cleaned with
PF-145HP degreaser, abrasive blasted to SSPC-SP 10, cleaned again with degreaser and allowed to dry.
b. Three flat steel bars, as above with strips of Class 2 damping treatment completely covering one 3 by 29 inch
(7.6 by 73.7 cm) face on each bar (bars from 4.5.8.1.2.a. may be used after measurement of bare-bar damping
characteristics). An aluminum constraining layer made of 5052 alloy conforming to ASTM B 209, 0.125 by 3
by 29 inches (0.3 by 7.6 by 73.7 cm) shall completely cover the damping treatment strips. The side of the
aluminum constraining layer to be bonded shall be cleaned with PF-145HP degreaser, sweep blasted (light
abrasive blasting), cleaned again with degreaser and allowed to dry.
The damping treatment strips shall be bonded to the steel bars using the bonding procedures detailed in 4.5.8.1.3.
The aluminum constraining layer shall be bonded to the damping treatment strips in accordance with 4.5.8.1.3. The
steel bars and the aluminum layers shall be cleaned with PF-145HP degreaser, abrasive blasted, cleaned again with
degreaser and allowed to dry. A coat of paint, with a maximum dry film thickness of 3 mils, may be applied to the
unbonded surfaces of the steel bars to protect against corrosion. The assembled test specimens shall be allowed to
set at 80 ± 9°F (27 ± 5 °C) for at least 96 hours prior to temperature conditioning and testing.
4.5.8.1.3 Bonding procedure. The grooved face of the damping treatment shall be bonded with adhesive
conforming to MIL-A-24456 to a steel bar which has been cleaned with PF-145HP degreaser, abrasive blasted to
SSPC-SP 10, cleaned again with degreaser and allowed to dry. Prior to bonding, the grooved face of the damping
treatment shall be cleaned with PF-145HP degreaser and allowed to dry. The adhesive shall be 0.10 ± 0.01 inch
(0.25 ± 0.03 cm) thick, evenly applied to the steel bar and the damping treatment pressed firmly down onto the
prepared bar surface. The aluminum constraining layer shall be bonded to the smooth face of the Class 2 damping
treatment previously bonded to the 3 by 29 inch (7.6 by 73.7 cm) steel bar. Adhesive conforming to MIL-A-24456
shall be applied to both the damping treatment surface and to the aluminum constraining layer with a thickness of
0.10 ± 0.01 inch. The constraining layer shall then be pressed firmly down onto the damping treatment surface.
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