H. Clean only with unused, expendable gauze sponges, or equivalent absorbent materials, using clean solvent, Series 92 (Ref AMM/SOPM 20-30-92) from dispensers.
J. Wipe off all solvent while wet with a clean cloth.
NOTE: The use of excess solvent shall be avoided.
K. Repeat steps H and J until no visible soil remains on the wiping cloth.
NOTE: Some primer may be removed during cleaning. The exposed metal surface need not be further treated if cleaning is accomplished per par. H, J, and K. If primer is completely removed, reprime surface after completion of all sealing.
L. Clean an area wider than the width of the finally applied sealant.
M. Remove all solvent from assembled faying surfaces by blast of oil-free and water-free air.
N. Make a final cleaning with a cloth just damp with solvent and wipe dry.
NOTE: Use of grease or wax base markings shall not be allowed in areas to be sealed. Any such markings inadvertently occurring shall be removed prior to sealing by cleaning with cleaning solvent. Successive applications of solvent and wiping shall be made until no visible trace of the marking remains on final wiping cloth.
O. Apply sealing compound. Refer to appropriate paragraphs for procedures as listed below:
(1)
Faying surface seals (Ref par. 4)
(2)
Injection seals (Ref par. 5)
(3)
Hole and slot seals (Ref par. 6)
(4)
Fillet seals (Ref par. 7)
(5)
Fastener sealing (Ref par. 8)
(6)
Aerodynamic smoother (Ref par. 9)
(7)
Installation and sealing of electrical seal fittings (Ref par. 10)
(8)
Fuel sealing (Ref par. 11)
(9)
Special sealing method for corrosion protection (Ref par. 12)
(10)
Protection of sealing materials (Ref par. 13)
(11)
Accelerated curing (Ref par. 14)
4. Apply Faying Surface Seal
A. Apply Permanent Seal
(1)
Sealant shall be applied to one faying surface with a roller to obtain a thin, uniform, continuous coating of sealant over entire faying surface area. Sealant shall be applied thick enough to completely mask surface underneath, yet thin enough to minimize size of the continuous bead required by par. (2). Recommended thickness range is 0.005 to
0.015 inch.
(2)
Sufficient sealant shall be applied so the space between the assembled faying surfaces is completely filled and a small excess is extruded continuously along the joint. Extruded sealant shall then be faired with a fairing tool so that a continuous, smooth fillet of approximately 0.06-inch depth is formed along the joint (Detail A, Fig. 201). This small fillet is necessary to assure adequate sealant contact with later applied fillet seals.
(3)
If possible, installation of all permanent fasteners shall be completed within the application time or squeeze-out life of sealant. If permanent fasteners cannot be installed within required time, temporary fasteners (e.g. wing-nuts, clecos, or bolts) shall be used in each fastener hole to hold parts firmly together until permanent fasteners can be installed. Removal of each individual temporary fastener shall be immediately followed by installation of a permanent fastener. If the drawing requires fastener to be sealed, fresh sealant shall be applied per par. 8. Maximum allowable separation of faying surfaces at shank of all permanent fasteners is 0.004 inch.
500
May 01/98 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 51-31-0 Page 203
B. Apply Removable Seal
(1)
Apply parting agent, Delchem X-769, or one part by weight of MIL-I-7444, vinyl tubing dissolved in four parts cyclohexonone, to one of the faying surfaces.
(2)
Apply BMS 5-95 sealant to opposite faying surface. See step A.(1).
(3)
Assemble parts when parting agent is dry to touch. See steps A.(2) and A.(3).
(4)
If one faying surface is acrylic, apply parting agent to nonacrylic surface (Detail B, Fig. 201).
CAUTION: WET PARTING AGENT REACTS WITH ACRYLIC AND MUST NOT BE APPLIED TO CONTACT ANY ACRYLIC SURFACE IN THE WET STATE.
5. Apply Injection Seal
A. Completely fill, with sealant, holes and joggles that require continuity of seal or block-off seals.
B. Inject sealant into one end of the cavity or injection hole if provided, with a Semco type flow gun, or equivalent, until sealant emerges from all other openings (Details A and B, Fig. 202).
CAUTION: TO PREVENT INCLUSION OF AIR IN SEALANT, NEVER COMPLETELY EMPTY A FLOW GUN. NEVER SEAL FROM BOTH ENDS OF CAVITY AS THIS TENDS TO CREATE AIR POCKETS AND POSSIBLE LEAKS WITHIN SEAL.
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