(j)
Do these steps to assemble the parts in less than 2 hours after you mix the B-2 material or in less than 20 minutes after you mix the B-1/2 material: 1) Put the rub pads in their positions.
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747-400 MAINTENANCE MANUAL
2) Use a clean roller or rub the surface with a clean cheesecloth to remove the air caught between the surfaces.
NOTE: Too much pressure can push the adhesive out from
____ between the rub pad and the airplane surface.
3) Remove unwanted adhesive with a clean cheesecloth that is moist with an appropriate solvent. Do not let the solvent go into the bond line.
4) Let the adhesive dry for 10 minutes before you apply the cure pressure. 5) Apply the cure pressure equally to the part in less than
3.0 hours after you mix the B-2 material or in less than
1.0 hour after you mix the B-1/2 material.
6) Cure the phenolic pads that are bonded to aluminum at a constant pressure of 5 to 14 pounds per square-inch (psi). Refer to the subsequent chart. ~................................................... | | Hours After You Apply | | | the Cure Pressure | | ............................. | Curing Temperature | Adhesive | Adhesive | | (°F) | Class B-1/2 | Class B-2 | ..................................................... | 77 |5 | 45 | 72 | | 72 |5 | 68 | 108 | | 67 |5 | 90 | 144 | | 62 |5 | 135 | 216 | | 115 |5 *[2] | 12 *[2] | 18 *[2] | | 185 |5 *[1] | 0.75 *[1] | 0.75 *[1] | | Bond line Temperature | | | | below cure Pressure | | | 2.......................….............….............1 *[1] More time on the cure pressure is necessary to heat
the adhesive from 70 to 180°F.
*[2] Optional cure temperature and time. You can use the optional cure temperature and time only with Pro Seal 890.
(k)
Remove the unwanted adhesive with a hardwood or plastic wedge.
(l)
Remove the remaining adhesive from the surface with a clean cheesecloth that is moist with solvent Series 98-1 (AMM 20-30-98).
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TASK 51-51-00-308-010
3. Bonded Phenolic or Stainless Steel Rub Pad Repair (No Heat Source Available)
_________________________________________________
NOTE: This procedure is recommended for a field repair of the bonded
____
rubstrips when a short cure time is necessary.
A. Standard Tools and Equipment
(1) Semco Sealing Gun
B. Consumable Materials
(1)
G00000 Wedge, Hardwood
(2)
G00000 Wedge, Plastic
(3)
A00250 Adhesive - BMS 5-126, Class B-1/2
(4)
A00251 Adhesive - BMS 5-126, Class B-2
(Pro-seal 890)
(5)
B00184 Solvent - BMS 11-7
(6)
B00316 Solvent - Aliphatic Naphtha - TT-N-95
(7)
B00153 Solvent - Toluene (Toluol), TT-T-548
(8)
A00322 Paper - Abrasive, Aluminum Oxide, 100
Grit (minimum)
(9)
G00000 Cloth - Abrasive, Aluminum Oxide, 100
Grit (minimum)
(10)
G00034 Cheesecloth - Clean
(11)
B00000 Pads - Scotch-brite, Aluminum Oxide
Impregnated, Type A
(12)
G00000 Spatula
(13)
G00000 Gloves - Rubber or Cotton
C. Repair the Bonded Rub Pads
S 118-030
(1)
Refer to the steps in the first procedure to apply adhesives on the mating surfaces.
S 348-031
(2)
Do these steps to apply a new pad:
(a)
Mix 22 (|2) parts (by volume) of BMS 5-26, Pro Seal 890 B-2 with actuator, to 100 parts (by volume) of the base component.
(b)
To install the new rub strip on the assembly, do these steps: 1) Make sure the mating surfaces are clean. 2) Put the rub strip flat against the assembly surface.
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