(b)
Dry the surfaces before the fastener and sealant installation.
S 397-014-B00
(3) Prepare the sealant.
(a)
Refer to the manufacturer's instructions to mix the sealant.
(b)
Mix the sealants as follows:
NOTE: The life of PR 1422 Class A and Class B is 1/2 or
____ 2 hours. The life of PR 1432 is 1 hour. Mix only the quantity that you can use during the life of the sealant.
1) PR 1422 Class A - 1 part A (accelerator) to 10 parts B (base)
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737-300/400/500MAINTENANCE MANUAL
2) PR 1422 Class B - 1 part A (accelerator) to 7-1/2 parts B (base) 3) PR 1432 - 1 part A (accelerator) to 15 parts B (base)
S 397-016-B00
(4) Apply PR 1422, Class B sealant.
(a)
Apply a small drop of the mixture to the countersunk area or below the head of the fastener.
(b)
Install the fastener immediately.
WARNING: DO NOT GET METHYL ETHYL KETONE (MEK) IN YOUR MOUTH OR
_______ EYES, OR ON YOUR SKIN. DO NOT BREATHE THE FUMES FROM MEK. PUT ON A PROTECTIVE SPLASH GOGGLE AND GLOVES WHEN YOU USE MEK. KEEP MEK AWAY FROM SPARKS, FLAME, AND HEAT. MEK IS A POISONOUS AND FLAMMABLE SOLVENT WHICH CAN CAUSE INJURY OR DAMAGE.
(c) Remove all unwanted sealant with clean cloths that are wet with methyl ethyl ketone.
S 397-017-B00
(5) Apply PR 1422, Class A sealant.
(a)
Use a brush to apply the PR 1422, Class A sealant mixture to the rework area.
(b)
Make sure you apply the sealant into the cracks around the fastener.
NOTE: It is necessary to have a continuous layer of sealant on
____
the rework surface.
S 397-008-B00
(6) Apply PR 1422, Class B sealant on top of the Class A sealant.
(a)
Use an extrusion gun or a spatula to apply the sealant to the rework areas.
(b)
If PR 1422 sealant is easy to apply, do these steps: 1) Apply the sealant until the surface of the sealant is not far below the surface of the adjacent wing. 2) Use a plastic scraper or a duckbill nozzle to remove the unwanted sealant.
3) Use a spatula or a plastic scraper to get the air bubbles out of the sealant.
(c)
If PR 1422, Class B sealant is not easy to apply, do these steps: 1) Apply a thick layer of PR 1422, Class B sealant. 2) Make sure the sealant surface is above the contour of the
wing surface. 3) Let the sealant dry. 4) Use a knife to remove the unwanted sealant that is above
the wing surface.
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737-300/400/500MAINTENANCE MANUAL
S 397-009-B00
(7) Apply PR 1432 sealant.
NOTE: Use PR 1432 sealant only for areas with many holes.
____
(a) Use a usual spray equipment to apply the PR 1432 sealant.
NOTE: For a best result, use a spray gun with an orifice
____ diameter of 0.085 inch minimum.
(b)
Use atomizing pressure of approximately 35 psig.
(c)
Fully fill the rework areas with PR 1432 sealant until the sealant extends higher than the edge.
(d)
Feather the surface.
(e)
If PR 1432 sealant is not easy to apply, do these steps: 1) Add 10 percent of toluene (by volume) to the base material. 2) Mix the solution. 3) Add the accelerator. 4) Constantly mix the base and the accelerator to decrease the
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