TM 1-1500-204-23-11
guide, pilot drill through the alignment
NOTE
holes into the composite substrate. Drill
the alignment holes in order to ensure
Using a grip length gauge, determine fastener
accurate patch location and install tem-
grip length by gauging material thickness after
porary fasteners in the holes as they are
drilling holes full size.
drilled to hold the patch irmly in place.
(ac) Place patch in place and measure the
(r)
Complete drilling all the pilot holes
fastener grip length required in each
through the substrate using the patch
fastener hole.
pilot holes as the guide. If the drilling
process begins to slow down or requires
(ad) Prime patch if required as speciied in
more pressure, the drill reamer has
the system speciic technical manual
become dull. Stop and replace the drill
and paragraph 6-7.
reamer.
(ae) Remove paint from skin in the repair
(s) If applying the patch to sandwich struc-
area by sanding as described in para-
ture, pot the core according to para-
(af) Remove sump or rymple cloth and vac-
(t)
Disassemble the patch from the sub-
uum repair cavity.
strate.
(ag) Seal the patch per paragraph 7-7g
(u) Using a 2000 rpm drill motor, drill guide,
below.
and a 1/64 undersized HSS drill bit,
drill all the patch holes except for the
(ah) Install fasteners and inspect according
marked alignment holes. Deburr the
holes drilled.
(ai) When repairing weight critical struc-
(v) Using temporary fasteners in the align-
tures, add weight of repair(s) and zone
ment holes, attach the patch onto the
location(s) on applicable nameplate.
composite substrate.
(aj) Apply inish system in accordance with
(w) Using a 2000 rpm drill motor, drill guide,
paragraph 7-13b or the system speciic
and a full-sized drill reamer, match drill
technical manual.
the patch/substrate combination.
g. Sealing Repairs. Sealants are applied to bolted
(x) Remove the patch from the substrate.
repairs on composite structure for prevention of
water/moisture intrusion, chemical damage, dissimilar
(y) Using a 2000-rpm drill motor, drill guide,
metal contact and fuel leaks, as well as to provide
and a 1/64-undersized HSS drill bit,
contour smoothness.
enlarge the alignment holes in the
patch. Deburr the holes.
(1) Facilities, Equipment and Materials. The
following equipment and materials are required: Injec-
(z) Attach the patch onto the substrate
tion Gun, Utility Knife, Sealant (See System Speciic
with temporary fasteners using full-size
Technical Manual), MIL-PRF-81733 Sealant (Local
holes that are adjacent to each of the
Procurement), Wiping Cloth, Masking Tape, Brush,
alignment holes used.
Solvent, Squeegee.
(aa) Using a 2000-rpm drill motor, drill guide,
(2) Preparation for Sealing a Repair.
and a full-sized drill reamer, match drill
the remaining holes in the patch/sub-
(a) Thoroughly mix the accelerator to a
strate combination.
smooth paste before combining with
base material.
(ab) Disassemble and deburr the remaining
holes in the patch.
(b) Determine the amount of each part to
mix. Follow the procedures described
in paragraph 6-17 for weighing and mix-
ing the two components. Mix the two
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