TM 1-1500-204-23-1
(b)
Repair scars, scratches, or surface
abrasion not penetrating through the facing, or fraying of
the edges of the backing by first cleaning the damaged
or frayed surface thoroughly and carefully using a clean
cloth moistened with methyl ethyl ketone, TT-M-261 (or
other approved cleaning agent).
(c)
Lightly sand the damaged surface
using No 280 grit abrasive cloth. Clean the surface
thoroughly using methyl ethyl ketone. Remove moisture
and solvents completely to prevent Inhibiting the curing
of the resin.
(d)
Apply one or two coats (depending
on seventy of the abrasion or fraying)of epoxy resin
using DTA cunning agent. Mix 100 parts by weight of
Epon 828MIL-R-9300 (FSCM 36131) with 10 parts by
weight of DTA O-D-1271. Brush the surface smooth
Methyl ethyl ketone may be added to lower viscosity of
the solution for brushing using a maximum of 5 percent
by weight
(e)
Over this coated surface, apply a
sheet of cellophane L-C-110, or polyvinyl alcohol (PVA)
film extending 2 or 3 inches beyond the surface.
Cellophane or polyvinyl alcohol film will prevent
exposure to the air, and will provide a smooth bubble-
free surface for the resin to cure.
(f)
Tape the cellophane or PVA film in
place and work out all air bubbles and excessive resin
by hand or by using a rubber squeegee.
(g)
Cure at room temperature for 24
hours. After the resin has cured or set, remove the
cellophane or PVA film for finishing
(6)
Repair and inspection of cuts and gouges
in backing Repair and inspection procedures are as
follows
(a)
Inspect for cuts and gouges in the
backing using special care to determine extent of the
damage.
(b)
Count the number of fiberglass plies
that have been damaged as accurately as possible.
Mark the number on the backing next to the damaged
area.
(c)
Repair
cuts
or
gouges
not
exceeding three layers of fiberglass by first removing
successive
layers
of
damaged
laminate
in
approximately oval patches (round corner rectangular
patches are permissible).
NOTE
Patches must form a step pattern as
shown in figure 9-39. Steps should
be at least 1/4 to 1/2 inch long Use a
cutting tool with a controlled cutting
depth to facilitate the cutout and to
avoid possible damage to the layers
underneath.
(d)
Remove these sections by peeling
from the center and working carefully back to the
desired perimeter of the cutout. Cut through the
overlaying ply in a series of cuts.
NOTE
Exercise care not to peel back or to
rupture
the
adhesion
of
the
lamination layers beyond the cutout
perimeter.
(e)
Scrape each step and wipe clean
with a cloth moistened with methyl ethyl ketone TT-M-
261
(f)
Cut pieces of fiberglass cloth, type
181, Cl 2, MIL-C-9084 to extract size, with the weave
direction such that they will overlay the original lay-up.
(g)
Use
the
wet
lay-up
technique.
Place the first ply of precut cloth on a clean lay-up table.
Spread 45 to 50 percent of resin by weight on the cloth,
using a squeegee to thoroughly impregnate all of the
fabric.
(h)
Lay-up the resin impregnated cloth
in the previously prepared cutout, being careful not to
entrap any air under the fabric. Repeat the same
procedure with the next ply.
(i)
Place the last ply dry in the cutout
after first coating the surface of the previous ply with
resin.
(j)
Replace each piece of fabric being
careful to maintain the wet resin content (by weight)
between 45-50 percent. Use resin and curing agent as
specified in paragraph 9-23d(3)(c).
(k)
Cover the repair with cellophane L-
C-110 or polyvinyl alcohol (PVA) film and press down to
smooth the patch and to expel air bubbles.
(l)
Cure at room temperature for 24
hours. After resign has cured or set, remove cellophane
or PVA film for finishing.
9-55
