TM 1-1500-204-23-11
2
Transfer the hole centerline and
(g) Impregnate the repair plies with laminat-
the reference points to a piece of
ing resin. Apply two of the repair plies to
Mylar. Use this Mylar as a guide in
the exit side of the fastener hole. Orient
redrilling the fastener hole follow-
the repair plies per the system speciic
ing illing.
technical manual in the same direction
as the original outer parent ply.
(e) Prepare Fastener Hole For Filler Appli-
cation.
(h) Prepare a small quantity (30 grams)
of adhesive/chopped iber mixture per
1
Lightly sand countersink area using
paragraph 6-17 with mrF = 5 (5 parts by
180 grit abrasive paper to remove
weight of chopped iber). Ensure iber
sealant, paint and other debris.
is chopped to 1/4 inch or smaller.
Vacuum area to remove sanding
residue. See paragraph 6-3 for
(i)
Apply Filler.
paint removal steps.
Carefully apply the adhesive/iber
1
2
Dry the repair area to remove sub-
mixture into the fastener hole and
surface moisture using per para-
ill to the top. Apply mixture in lay-
ered amounts to avoid air entrap-
ment.
Clean fastener hole and counter-
3
sink area using a cotton tipped
Fair mixture with a spatula and
2
applicator, wiping cloth and solvent.
wipe off excess with clean, dry,
Thoroughly clean the area with
wiping cloth.
repeated wiping until no residue is
left on the cotton tipped applicator
or the wiping cloth. Allow the sol-
NOTE
vent to evaporate for a minimum of
Some potting compounds shrink during cure.
30 minutes. See paragraph 6-7 for
If using a mixture that is likely to shrink, build
surface preparation steps.
compound slightly above the part surface.
NOTE
(j)
Apply the remaining repair plies,
For lightly loaded or secondary structure,
impregnated in step (g), to the entrance
only one ply may be necessary. Refer to
side of the fastener hole. Orient the
the system speciic technical manual for the
repair plies per the system speciic
required number of plies.
technical manual in the same direction
as the original outer parent ply. Work
out any air bubbles from both the upper
(f)
Prepare plies of repair fabric according
and lower plies.
to paragraph 6-16 to overlay the repair.
Typically two or more overlay plies are
used on each side of a potted repair on
load-bearing structures.
Pressure must be applied to adhesive within
the pot life of the resin. For ambient temper-
atures in excess of 90 F, decrease this time
by 50%. An unsatisfactory repair will result
Reduced strength will result if the incorrect
if the resin gels before adequate pressure is
mix ratio is used, if an excessive amount
applied and may result in loss of structural
of air is introduced into the adhesive during
integrity. Select a heat blanket (if required)
mixing, or if mixing is inadequate and may
and all necessary vacuum bag materials prior
result in loss of structural integrity.
to mixing resin.
Failure to observe the correct number of repair
Failure to properly cure adhesive in accor-
plies, the correct repair ply orientation, the
dance with the speciied cure cycle will result in
correct repair ply overlap and removal of all
reduced repair strength may not be detectable
pieces of vacuum bagging ilm will reduce the
by visual or nondestructive inspection. This
strength of the repair and may result in the
may result in loss of structural integrity.
loss of structural integrity.
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