A
757
MAINTENANCE MANUAL

 2) Write the date you mix the sealant, sealant type, class, supplier, and date when the sealant cannot be used. 3) Discard all sealant kept more than 21 days at -40°F (-40°C). 4) Discard all sealant kept more than 7 days at -20°F (-28.9°C).
 S 398-040
 (3)  
Sealant application time

 (a)  
The time in which you can apply the mixed BMS 5-26 Type II Class B-2 sealant is 2 hours at 77°F (25°C) and 50% relative humidity.

 (b)  
The time in which you can apply the mixed Pro-Seal 860, B 1/6 is 10 minutes at 77°F (25°C) and 50% relative humidity.

 S 398-041
 (4)  
BMS 5-26 Type II sealant squeeze-out life

 (a)  
Squeeze-out life is the length of time you can use the sealant for structure assembly when you apply faying surface seals.

 (b)  
The time, shown in Fig. 804, is the maximum time between when you start to thaw the sealant or mix sealant that is not frozen and the final attachment of mating surfaces.

 S 398-042
 (5)  
Sealant curing

 (a)  
You must let the BMS 5-26 Type II sealant cure for the minimum time (Fig. 804) before you continue maintenance operations in the fuel tank or refuel the fuel tank.

 (b)  
Pro-Seal 860, B 1/6 sealant can touch fuel after 2 hours and has a cure time of 4 hours.

 WARNING: DO NOT START OR STOP THE AIR BLOWER WITH THE AIR HOSE IN
_______ THE FUEL TANK. OBEY ALL SAFETY PRECAUTIONS WHEN YOU USE WARM AIR. FAILURE TO OBEY THE SAFETY PRECAUTIONS COULD CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 CAUTION: DO NOT APPLY SEALANT WHEN THE STRUCTURE TEMPERATURE IS
_______ LESS THAN 50°F (10°C) OR MORE THAN 140°F (60°C). THE SEALANT WILL NOT CURE CORRECTLY IF THE STRUCTURE TEMPERATURE IS OUT OF RANGE.
 (c)  The best conditions to cure the sealant are at an ambient temperature of 77°F (25°C) and a relative humidity of 50 |5 percent, with a good flow of air in the area. 1) Relative humidity is an important factor in the cure time
 for sealants. a) You must know the relative humidity at all times during the sealant operations.
 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 28-11-00
 ALL  ú ú 01 Page 817 ú Mar 20/94

A

757
MAINTENANCE MANUAL

 b)  If the relative humidity is less than 40 percent it slows the cure of the sealant.
 c)  To increase the relative humidity, let moist, warm air, at a temperature of less than 120°F (49°C), flow over the repair area.
　
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：757 AMM 飛機維護手冊 燃油 CHAPTER 28 - FUEL 1(124)