MIL-DTL-25988C
tensile strength, elongation, hardness, and volume change tests shall be conducted in
accordance with 4.5.1.
4.5.6 Compression set
Except where otherwise specified herein, compression set shall be determined in accordance
with ASTM D 395, method B. Specimens for type I materials shall be two O-rings. Two circular
plied-up buttons with dimensions of 1.129 ± 0.001 inches (28.677 ± 0.25 mm) diameter and
approximately 0.5 inch (12.7 mm) thick shall be cut from sheet for type II material.
4.5.6.1 Oil aged
Compression set shall be determined on specimens aged 70 hours at the applicable
temperature as specified in TABLE II, immersed in AMS 3021. The compression set plates for
testing type I material shall be approximately 0.375 inch by 2 inches by 4 inches (9.52 mm by
50.8 mm by 102 mm). There shall be six, one-fourth inch (6.35 mm) bolt holes, one on each
corner and one located in the middle of each 4-inch (102 mm) edge and on the center line of the
corner holes. There shall also be one-fourth inch (6.35 mm) holes through the middle of each
half of the plates to allow fluid to be in contact with the inside diameter of the O-rings. The
compression set plates for type II material shall be in accordance with ASTM D 395. The
original thickness of the specimens shall be measured and the test fixtures shall be assembled
using two test specimens. The specimens shall be compressed 25 percent. The test fixture
shall be placed in a 1 liter stainless beaker. The beaker shall be fitted with a suitable vented
stainless steel cap. The cap shall be sealed with an O-ring conforming to type I, class 1 of this
specification (size 240, MIL-R-25988/1, has been used). The beaker shall be placed in a
suitable oven at the applicable temperature with vent open. After the fluid has reached the test
temperature (approximately two hours) the vent shall be closed and the beaker left in the oven
for a total aging time of 70 hours. At the end of the aging time, the specimens shall be removed
from the compression plates immediately and allowed to cool on paper towels for 30 minutes.
The excess fluid shall be blotted from the specimens and the final thickness measurement
made.
4.6 Packaging inspection
Sample packages and packs and the inspection of the packaging, packing and marking for
shipment and storage shall be in accordance with the requirements of section 5 and the
documents specified herein or as otherwise specified in the control or order.
5. PACKAGING
5.1 Packaging
For acquisition purposes, the packaging requirements shall be as specified in the contract or
order (see 6.2). When packaging of materiel is to be performed by DoD or in-house contractor
personnel, these personnel need to contact the responsible packaging activity to ascertain
packaging requirements. Packaging requirements are maintained by the Inventory Control
Point's packaging activities within the Military Service or Defense Agency, or within the military
service's system commands. Packaging data retrieval is available from the managing Military
17
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business