and all necessary vacuum bag materials prior
(o) Cure the repair using the cure cycle
to mixing resin.
from the system speciic technical man-
Prepare a small quantity (30 grams) of
temperature cure is required, use a
heat lamp, heat blanket or other heating
equipment. Place a thermocouple next
Calculate the number of iller patch plies
to the repair on the same side as the
required per system speciic technical
heat source. If room temperature cure
is used, remove release ilm, caul plate,
and vacuum bag after a minimum of 8
(k) Prepare plies of repair fabric to ill the
hours. Allow to dwell at room tempera-
fastener hole and overlay the repair
ture for a minimum of 5 days.
(p) Redrill/Countersink Hole.
Failure to observe the correct number of repair
If the resin is cured at room temperature, DO
plies, the correct repair ply orientation, the
NOT smooth or drill the hole for at least 24
correct repair ply overlap and removal of all
hours after the resin sets.
pieces of vacuum bagging ilm will reduce the
strength of the repair and may result in the
Lightly sand any squeezed out iller
loss of structural integrity.
lush with part surface using 180
grit abrasive paper.
Using the template fabricated
Do not use unidirectional material.
above, carefully locate a drill guide
containing the correct drill bushing
Stack the repair plies into the tapered
for the hole to be redrilled. Secure
fastener hole cleanout until it is illed.
the drill guide to the part with a
Consult system speciic technical man-
ual to determine if ply orientation for fas-
tener hole repair is required.
Redrill and countersink the
repaired fastener hole per para-
(m) Apply overlay plies to the upper and
lower repair surfaces as shown in ig-
required, use a countersink micro
stop to prevent countersinking too
system speciic technical manual in the
same direction as the original outer par-
(n) Layup the vacuum bag and heat blanket
Sand the area smooth with 180 grit
abrasive paper. Vacuum sanding
metal caul plates on both sides of the
dust from repair area. Wipe with
repair. These plates should extend 1
clean, dry wiping cloth to remove
to 2 inches beyond the repair area and
will ensure even pressure is applied to
the repair. Refer to the system speciic
Apply inish system in accordance
technical manual for the porous release
ilm, bleeder material and the number of
tem speciic technical manual. Use
care not to apply inish system in
fastener hole or countersink area.
f. Fastener Hole Delamination Repair. This repair
Failure to properly cure adhesive in accor-
is applicable to fastener holes with delaminations
dance with the speciied cure cycle will result in
exposed to the edge of the hole only and uses the
reduced repair strength may not be detectable
vacuum injection technique. Refer to igure 7-58 for the
by visual or nondestructive inspection. This
Process Flow Diagram for Fastener Hole Delamination
may result in loss of structural integrity.
Repair (Vacuum Injection).