F. Repair the Teflon Rub Pad
S 348-021
(1) Mix each adhesive component. Mix the base compound with the activator per the manufacturers instructions. Do not make the adhesive thin.
NOTE: You can use the adhesive mix for a maximum of 20 days if you
____ keep the mixture at a temperature less than -40°F. Make sure you keep the mixture in sealant gun tubes or in aluminum toothpaste type tubes. Make a mark on each container with the material name and the expiration date.
S 348-022
(2) Apply a thin constant layer (approximately 50 grams for each square foot) of the mixture on each mating surface.
NOTE: Use a spreader that has serrations to apply the adhesive on
____
a large mating surface.
S 438-023
(3) Put the teflon rub pad on the airplane surface. Apply pressure to make sure the rub pad makes full contact with the airplane surface.
NOTE: Make sure the adhesive has a sufficient thickness to let the
____ adhesive flow around the edges of the rub pad when the cure pressure is applied.
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747-400 MAINTENANCE MANUAL
S 348-024
(4) Cure the pad at 75 to 80°F. The cure time to handling strength is as follows:
NOTE: The time to a full cure is one week or more.
____
~......................................................
| Adhesive | Handling Time |
........................................................
| BMS 5-26, Class B-2 | 48 hours |
........................................................
| BMS 5-95, Class B-1/2 | 24 hours |
........................................................
| BMS 5-95, Class B-2 | 48 hours |
2...............................…......................1
S 228-025
(5)
You can make a test of the cure strength with a Durometer. Before you touch the rub pad, the Rex Model A Durometer must read 30 and the Shore A Durometer must read 20.
S 348-026
(6)
You can apply heat to increase the speed of the cure time, up to a temperature of 120°F. The cure time will be reduced by 50 percent for each 20°F rise in temperature. Temperatures below 75°F will increase the cure time.
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747-400 MAINTENANCE MANUAL
WING LEADING EDGE CAVITY ALUMINUM FOIL TAPE - REPAIRS
_____________________________________________________
1. General
______
A. This procedure contains one task:
(1) The task is to repair the aluminum foil tape.
B. The protection is given to the electrical/electronic wiring in the leading edge by an aluminum foil tape applied to a part of the inner surface of the nonmetallic leading edge skins.
C. The tape does the dual functions:
(1)
The tape prevents a possible direct stroke contact to the wires below the tape.
(2)
The tape gives the electromagnetic shielding from the fields set up by a lighting strike.
TASK 51-61-01-308-001
2. Aluminum Foil Tape - Repair
___________________________
A. Consumable Materials
(1)
G00291 Tape - Aluminum Foil, Scotch Brand
Industrial Tape No. 425 with Liner
(0.003 Inch Thick)
(2)
B00083 Solvent - Aliphatic Naphtha, TT-N-95
(3)
B00535 Solvent - Tetrachloroethylene
(Perchloroethylene), Technical, O-T-236
(4)
B00148 Solvent - Methyl Ethyl Ketone (MEK),
TT-M-261
B. Procedure
S 028-007
WARNING: THE FINISHES, CLEANERS, THINNERS, AND SOLVENTS CONTAIN TOXIC
_______ AND/OR FLAMMABLE COMPONENTS. DO NOT BREATHE THE VAPORS AND MIST. USE WITH SUFFICIENT VENTILATION. DO NOT GET THESE TOXIC COMPONENTS IN YOUR MOUTH OR EYES, OR ON YOUR SKIN. PUT ON A PROTECTIVE SPLASH GOGGLE AND GLOVES. KEEP FLAMMABLE MATERIALS AWAY FROM SOURCES OF IGNITION.
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