3) Prepare the Cement EC-2216B/A a) Mix equal parts by weight of EC-2216B (base) and EC-2216A (accelerator).
NOTE: The pot life of the mixed adhesive is about
____ 90 |10 minutes at 70-80°F.
(f)
Apply a light layer of adhesive to the two mating surfaces.
(g)
Put the two surfaces together immediately after you apply the adhesive.
(h)
Remove the unwanted adhesive and apply to the surface with tape if it is possible.
(i)
Put a cover on top of the adhesive not used to keep it wet.
S 348-007
(7) If the adhesive decreases the intensity of light in the lens repaired area, make the lens surface smooth again as follows:
NOTE: Parts bonded with PS-30 or PS-18 can be made smooth again
____
after 5 hours at ambient temperature.
Parts bonded with EC-2216 B/A must be dried for 24 hours at ambient temperature, or 130 |10 minutes at 160 |10°F before you touch or use them.
(a)
Remove the tape and flush all areas without tape with clean water to remove the dirt and the grit.
(b)
Clean with soap and water.
NOTE: To clean the area, you can use a soft cloth or a chamois
____ Only use the cloth or the chamois to move the water to the plastic. Do not rub the plastic with the cloth or the chamois. Rub the plastic with your hand to quickly find and remove all abrasive material.
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A 747-400 MAINTENANCE MANUAL
(c) You must use a clean, moist chamois to dry the area.
NOTE:____ Use the approved cloth if you are careful not to rub the acrylic after it is dry.
(d) (e) Lightly rub the acrylic with a cloth soaked with aliphatic naptha to remove the oil and grease.Dry the area with the approved cloth.
NOTE:____ Do not rub acrylic plastics with a dry cloth. To remove a light dust film or electrostatic charges, rub the surface with a clean, moist chamois or a clean, moist approved cloth.
(f) Rub sandpaper along the plastic surface that has scratches.
NOTE:____ Start with 280 grit wet or dry abrasive paper and continue with smoother grit paper (320, 400, 600) until you get the necessary finish. You must wind abrasive paper around a rubber block with a durometer indication of 35 |5, Shore A scale, or a wood block wound with the approved cloth. Keep the surface soaked with water while you use the sandpaper. The plastic surface will become too hot if you are not careful. Stay in the repaired area when you sand to get a smooth repair that is continuous with the adjacent area.
(g) If you make deeper scratches from the sandpaper, you must remove them.
NOTE:____ Clean with water each time you change the grit. After you get a smooth, continuous surface, clean with water until you remove the grit.
(h) Polish the lens.
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A
747-400 MAINTENANCE MANUAL
S 418-008
(8)
Install the lens.
S 428-009
(9)
Install the forward fairing of the wingtip (AMM 57-23-01/401).
E. Polish the Lens
S 348-010
(1) Machine polish the lens.
(a)
It is recommended you polish with a machine when the equipment and an approved person are available.
(b)
You must balance the items as follows on the machine to prevent the acrylic to become too hot. 1) Contact pressure 2) Feed rate 3) Wheel speed
(c)
Use a stitched muslin wheel and Learock S-30 buffing compound.
NOTE: Change the direction of "feed" frequently and use only
____ light pressure. To make it shiny, polish with a loose, open, unstitched wheel with spacers and Learock 888 buffing compound. (To make spacers, remove all the muslin disks, and with scissors, cut half of them to 1/2 the initial diameter. Assemble the wheel, again and replace the large disks with the small ones). Continue this procedure to replace the large disks with the small ones. If you use this wheel it will decrease the surface heat a large quantity caused by friction.
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