CAUTION: BE CAREFUL WHEN YOU MIX AND MAKE THE SEALANT SMOOTH TO
_______ KEEP AIR BUBBLES TO A MINIMUM. AIR BUBBLES CAN MAKE THE SEALANT DIFFICULT TO APPLY.
(c)
Before you mix the sealant, stir each component in its container to make sure each is homogeneous.
(d)
Carefully mix the total contents of the base and accelerator containers or mix at a measured ratio of 100 parts of base to 90 parts of accelerator by weight or by volume.
NOTE: The material is normally supplied in premeasured kits
____
to give the correct ratio.
(e) Stir slowly until you get a homogeneous mixture.
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747-400 MAINTENANCE MANUAL
S 398-211
WARNING:_______ DO NOT BREATHE THE FUMES FROM THE SECONDARY FUEL BARRIER
SEALANT (BMS 5-81, TYPE II). KEEP THE SEALANT AWAY FROM
SPARKS, FLAME OR HEAT. THE SEALANT IS POISONOUS AND FLAMMABLE
AND CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
CAUTION:_______ DO NOT APPLY THE SECONDARY FUEL BARRIER SEALANT (BMS 5-81,
TYPE II IF THE AIR TEMPERATURE IS LESS THAN 60°F (15°C) OR THE
RELATIVE HUMIDITY IS MORE THAN 95 PERCENT. THE SEALANT WILL
NOT CURE CORRECTLY IF THE TEMPERATURE AND RELATIVE HUMIDITY
CONDITIONS ARE NOT IN THE LIMITS.
(9) Apply two layers of BMS 5-81, Type II sealant with a flat, bristle brush.
NOTE: At 77 |5°F (25 |2.8°C) and 50 |5 percent relative humidity,
____ the approximate application time of sealant, BMS 5-81 Type II, Class I is 120 minutes. The approximate application time of sealant, BMS 5-81, Type II, Class 2 is 30 minutes. Higher temperatures make the application time shorter. Lower temperatures make the application time longer.
CAUTION: DO NOT PERMIT THE THICKNESS OF THE APPLIED SEALANT TO BE
_______ MORE THAN 0.020 INCH (0.5MM). DAMAGE TO EQUIPMENT CAN OCCUR.
(a)
Make sure the total thickness of the two layers of applied sealant is 0.005 to 0.010 inch (0.13mm to 0.25mm).
(b)
For horizontal surfaces, let the sealant dry a minimum of 1/2 hour between layers.
(c)
For vertical surfaces, let the sealant dry a minimum of 2 hours between layers.
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(d) Thickness Measurement Instrument, 602-816 and Thickness Measurement Probe, 602-128 can be used to make sure the sealant has the correct thickness.
S 398-213
(10)
Cure the sealant.
(a)
The cure rates of the sealant are as follows:
NOTE: A cure temperature of more than 80°F (26.7°C) is
____
recommended for the best results.
~.............................................................................. | TABLE I BMS 5-81 CURE RATES | ................................................................................ | | CURE CONDITIONS | | ................................................................. | | DRY HARD (HOURS) *[1] | DRY THROUGH (HOURS) *[2] | | ................................................................. | CURE | TYPE II, | TYPE II, | TYPE II, | TYPE II, | | TEMPERATURE | CLASS 1 | CLASS 2 | CLASS 1 | CLASS 2 | ................................................................................ | 75 |5°F | 50 | 8 | 96 | 24 | | 23.8 |2.8°C | | | | | ................................................................................ | 100 |5°F | 18 | 2.5 | 36 | 3.5 | | 37.8 |2.8°C | | | | | ................................................................................ | 125 |5°F | 7.5 | 1.5 | 15 | 2.5 | | 51.7 |2.8°C | | | | | ................................................................................ | 150 |5°F | 2.5 | 1.5 | 5 | 2 | | 65.6 |2.8°C | | | | | 2..............…...............…...............…...............…...............1 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：747-400 AMM 飞机维护手册 燃油 FUEL 1(109)
