Piper Cherokee Six - Page 137

PIPER
CHEROKEE
SIX SERVICE
MANUAL
area.
The aluminum
should
also
be
covered
with
cellophane.
f. Prepare
a
patch of
fiberglass
mat
and cloth
to
cover
an area
two inches
larger
than
the hole.
g.
Mix
a small
amount
of resin
and
catalyst,
enough
to be
used for
one
step at a
time,
according
to
kit
instructions.
h. Thoroughly
wet
mat and
cloth with
catalyzed
resin.
Daub resin
on mat
first, and
then
on cloth.
Mat
should
be applied
against
structures
surface
with
cloth
on top.
Both pieces
may
be wet
out on
cellophane
and
applied
as a sandwich.
Enough
fiberglass
cloth
and mat
rein-
forcements
should be
used to
at least replace
the amount
of
reinforcements
removed
in order
to
maintain
the original
strength.
If damage
occurred
as
a stress
crack, an
extra
layer or
two of
cloth
may
be used
to
strengthen
area.
i. Lay patch
over
hole on
inside of
structure,
cover with
cellophane,
and
squeegee
from
center
to edges
to remove
all air bubbles
and
assure adhesion
around
edge
of hole. Air
bubbles
will
show white
in the
patch and
they should
all
be worked
out to the
edge. Remove
excess
resin before
it gels
on the
part. Allow
patch
to cure
completely.
j.
Remove
cardboard
or aluminum
sheet
from
outside
of hole
and rough-sand
the
patch
and edge
of hole.
Feather
edge of
hole about
two
inches into
undamaged
area.
k. Mask
area
around hole
with
tape and paper
to protect
surface.
Cut
a piece of
fiberglass
mat
about one
inch
larger than
the
hole and
one or
more pieces
of
fiberglass
cloth
two inches
larger
than
the
hole. Brush
catalyzed
resin over
hole,
lay mat
over
hole and
wet out
with
catalyzed
resin.
Use a daubing
action
with brush.
Then
apply additional
layer or
layers of
fiberglass
cloth
to build
up patch
to
the surface
of structure.
Wet out
each
layer thoroughly
with resin.
1. With
a squeegee
or broad
knife,
work out
all air
bubbles
in the patch.
Work
from
center
to edge,
pressing
patch firmly
against
the structure.
Allow
patch
to cure for
15 to 20
minutes.
m. As
soon as
the patch
begins
to set up,
but while
still rubbery,
take
a sharp
knife and
cut
away extra
cloth
and mat.
Cut on outside
edge
of feathering.
Strip
cut edges
of structure.
Do
this before
cure
is complete,
to save
extra
sanding.
Allow patch
to cure
overnight.
n. Using
dry
80 grit
sandpaper
on
a power
sander
or sanding
block,
smooth
patch
and
blend
with surrounding
surface.
Should air
pockets
appear
while sanding,
puncture
and
fill
with catalyzed
resin.
A hypodermic
needle
may
be used
to fill cavities.
Let cure
and resand.
o. Mix
catalyzed
resin
and
work into
patch
with
fingers.
Smooth
carefully
and
work
into
any
crevices.
p. Cover
with
cellophane
and squeegee
smooth.
Allow
to
cure completely
before
removing
cellophane.
Let
cure and
resand.
q. Brush
or spray
a coat
of catalyzed
resin to
seal patch.
Sand
patch,
finish
STRUCTURE
Issued: 8/17/72
1F17