(h) While still tacky, apply patch to
cemented area on the cell, centering patch over
damaged area. With the one-inch roller (item 20, table
2-11) or similar tool, roll the patch to the cemented area
and roll it down a 1/2 inch to 1 inch across at a time, so
as not to trap air between the patch and cell.
(i) Place a 10 to 25 pound force by
damping (C-damp (item 21, table 2-11) and two pieces
of wood (item 22, table 2-11)), shot bag (item 23, table
2-11), etc., if practical on repair. Polyethylene, waxed
paper (item 24, table 2-11) should be placed between
the patch and force applying device to prevent sticking
of the force applying device to the repair.
(j) Allow repair to remain undisturbed
for at least 8 hours. The fuel cell should not be returned
to service for 24 hours after a cold patch has been
applied, which is the time required for the adhesive to
become fully cured, at a temperature between 60 °F to
workmanship, no loose edges, no voids and adhesive
fully cured. If there is a defect in repair, recement per
External and Internal Surface Hole Repair,
Including Through Hole.
Acetone and repair adhesives are
flammable and toxic. Keep away
from heat, sparks and open flame.
Wear safety glasses, gloves and
protective clothing to prevent
contact. Wear a NIOSH approved
air-purifying respirator for organic
ventilated area. If contact occurs,
flush areas with water and get
medical attention. If ingestion
occurs get medical attention at once.
(a) Clean innerliner of fuel cell at least
3 1/4 inches larger in all directions around hole. Use a
piece of dean cheesecloth (item 16, table 2-11)
dampened with acetone (item 3, table 2-11).
(b) Lightly, hand buff innerliner of fuel
cell around hole using emery cloth (120 grit) (item 17,
table 2-11), 3 1/4 inches in all directions.
(c) Clean buffed area. Use a piece of
dean cheesecloth (item 16, table 2-11) dampened with
acetone (item 3, table 2-11). The surface must be clean
and dry in order to apply patch.
(d) Cut a patch from internal patch
material fabric (item 19, table 2-11). The patch should
be 3 inches larger in all directions around hole. Lightly,
hand buff gum side (side with dull finish) of patch with
emery cloth (item 17, table 2-11). Remove buffing dust
by wiping patch with cheesecloth (item 16, table 2-11)
dampened with acetone (item 3, table 2-11). Wear
gloves (item 4, table 2-11).
flammable and should be kept
away from any ignition source.
Adhesive materials should be kept
containers in a cool, dry place.
(e) Refer to paragraph c(1)(e) for
The adhesive should be
used sparingly. Two (2) thin,
even coats will provide better
adhesion than two thick, puddled
coats. Acetone is used as a
solvent for the adhesive and,
appears dry to touch, it may be
freshened or made tacky again by
application of this solvent.
beyond buffed areas.
(f) Apply one coat of adhesive (item
18, table 2-11) to buffed side of patch and buffed area
of cell innerliner, allow to dry 20-60 minutes.
To determine if adhesive is tacky,
test it by pressing a knuckle
surface and withdrawing it (if
practical). Proper tackiness is
achieved when a few threads of
adhesive stick to the knuckle.
This procedure is referred to as
the knuckle test.
Change 2 2-63