MIL-PRF-2912G (SH)
lining of the 12 by 12 inch panel shall be cut through to the steel with a sharp knife to give three strips, each 1 by
12 inches, as shown on Figure 1. The method for determining adhesion to steel and ply adhesion shall be as shown
on Figure 1. The panel shall be supported in a horizontal position with the lining on the underside. A sufficient
length of the outer ply of one strip shall be separated from the inner ply to permit attachment of a clamp. A dead-
weight load of 15 pounds (clamp plus weight) shall be suspended from the outer ply, and the rate of separation of
the ply measured. The test shall be performed on the outer ply of each of the three strips; then it shall be
performed on the inner ply of each of the three strips to evaluate the adhesion between the rubber and the steel.
Results shall conform to the specification.
4.6.4 Oxygen pressure aging. Oxygen pressure aging shall be performed using the equipment and
procedure specified in ASTM D 572.
4.6.4.1 Effect of aging on tensile and elongation properties. Three dumb-bell specimens prepared as
specified in 4.6.2 shall be used. After aging they shall be tested by the procedure specified in 4.6.2.
4.6.4.2 Effect of aging on adhesion. A 4 by 9 inch section cut from one of the 12 by 12 inch panels
having two 1 by 9 inch adhesion test strips in place shall be used. After aging, the specimen shall be conditioned at
room temperature for not less than 20 hours nor more that 24 hours before testing. Adhesion tests shall be
performed as specified in 4.6.3 except that dead-weight load of 12 pounds shall be used.
4.6.5 Immersion in acid. The specimens shall be immersed for 46 hours in a 20 percent solution
consisting of a concentrated sulfuric acid using water as a dilutant maintained at 158 plus or minus (±) 2 ºF.
4.6.5.1 Effect of acid immersion on weight. The specimens and procedure shall be as described in ASTM
D 471 with the following exceptions. After removal from the sulfuric acid solution, the specimens shall be rinsed
briefly in tap water (not longer than 5 seconds immersion), carefully dried and let stand on a galvanized wire
screen for 1 hour before weighing.
4.6.5.2 Effect of acid immersion on tensile strength and elongation properties. The specimens shall be
as specified in 4.6.2. The procedure shall be as specified in ASTM D 471 with the following exceptions. After
removal from the sulfuric acid solution, the specimens shall be rinsed briefly in tap water, carefully dried and let
stand on a galvanized wire screen for not less than 20 hours nor more than 24 hours before testing. The tensile
strengths after immersion shall be based on the original cross section of the constricted portion of the dumb-bells.
4.6.6 Immersion in oil. The specimens shall be immersed for 46 hours at room temperature in ASTM
reference oil number IRM 903 as specified in ASTM D 471.
4.6.6.1 Effect of oil immersion on volume. The specimens and procedure shall be as specified in ASTM
D 471. The final weighing shall be completed within 3 minutes after removal from the special testing oil.
4.6.6.2 Effect of oil immersion on tensile strength and elongation properties. The specimens shall be as
specified in 4.6.2. The procedure shall be as specified in ASTM D 471. The tensile strengths after immersion
shall be based on the final cross section of the constricted portion of the dumb-bells.
4.6.6.3 Effect of oil immersion on adhesion. A 4 by 9 inch section cut from one of the 12 by 12 inch
panels and having two 1 by 9 inch adhesion strips in place shall be completely immersed in the oil. At the end of
the immersion period the section shall be dipped in acetone, wiped-dry, and tested by the procedure specified in
4.6.3, except that a dead-weight load of 12 pounds shall be used.
4.6.7 Plastic flow. A 4 by 4 inch plate with the rubber lining on one face shall be cut from one of the 12
by 12 inch plates. The small plate shall be laid in a horizontal position on a firm base with the rubber lining facing
upward. A cylindrical flat indentor of 1 square inch bearing area shall be centered on the rubber lining. The
indentor shall be pressed into the rubber with a total dead-weight load of 100 pounds (including the weight of the
indentor). The original depth of penetration shall be measured 30 seconds after application of the load. Depth of
6
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business