MIL-STD-1568 Materials And Processes For Corrosion Prevention And Control In Aerospace Weapons SystemsThis standard establishes the requirements for materials, processes and techniques, and identifies the tasks required to implement an effective corrosion prevention and control program during the conceptual, validation, development and production phases of aerospace weapons systems. The intent is to minimize life cycle cost due to corrosion and to obtain improved reliability.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22

MIL-STD-1568C

5.6 Environmental sealing.

5.6.1 Detail requirements. All joints and seams located in exterior or internal corrosive environments, including those in landing gear wells, control surface vents, attachment wells and structure under fairings shall be faying surface sealed with sealant containing a chromate corrosion inhibitor conforming to MIL-PRF-81733 except when operational temperature exceeds 225 °F (107 °C). Those areas that operate at temperatures from 225 °F (107 °C) to

275 °F (135 °C), use sealant conforming to SAE AMS3276. For scaling areas that operate at

275 to 500 °F (135 to 260 °C) sealant conforming to SAE AMS3374 shall be used. Sealants used in integral fuel tanks shall conform to SAE AMS-S-8802 or SAE AMS3276. Removable panels and access doors shall be sealed, either by mechanical seals or separable faying

surface sealants conforming to MIL-S-8784 or SAE AMS3284. High adhesion sealant such as SAE AMS-S-8802 or SAE AMS3276 may also be used for access door sealing provided a suitable parting agent is used on one surface.

5.7 Fastener installation.

5.7.1 Detail requirements. All permanently installed fasteners except as noted in 5.7.3 (all fasteners not normally removed for regular access or servicing) used in areas up to

225 °F (107 °C) shall be wet installed with either a corrosion inhibiting sealant conforming to MIL-PRF-81733 or an epoxy primer conforming to MIL-PRF-23377, Type I, Class C1, or C2, or a MIL-PRF-85582, Type I, Class C1 or C2 material that does not contain water. In high temperature areas exceeding 225 °F (107 °C), Type I, Class 1 or 2 epoxy primer or a sealant that is suitable for the thermal environment shall be used. Fasteners in integral fuel tanks shall be installed with wet sealant conforming to SAE AMS-S-8802 or SAE AMS3276. Sealant or corrosion inhibiting coatings other than those specified herein shall not be used unless approval has been obtained by the procuring activity.

5.7.2 Removable fasteners. Quick release fasteners and removable fasteners penetrating exterior surfaces, shall be designed and installed so as to provide a seal to prevent moisture or fluids from entering. Holes for these fasteners shall be primed with MIL-PRF-23377, Type I, Class C1 or C2, or MIL- PRF-85582, Type I, Class C1 or C2 epoxy primer and allowed to completely dry prior to installing the fastener.

5.7.3 Fasteners in titanium. Titanium, Monel, and stainless steel fasteners installed in titanium structures may be installed dry, unless sealing is required for liquid tightness, pressurization, or the fastener is also connected to aluminum.

5.7.4 Monel and stainless steel fastener. Monel fasteners or stainless steel fasteners shall be coated with cadmium or aluminum when used in contact with aluminum components.

5.7.5 Fasteners in graphite composites. Fastener materials for use in graphite composite structures shall be titanium or A286. Cadmium plated fasteners and aluminum fasteners shall not be used. Fasteners shall be wet installed using sealants as specified in 5.7.1.