Structural Repairs - Piper PA-24 Comanche Service Manual

PIPER COMANCHE SERVICE MANUAL
k,
Mask
ara
around hole with
tape
and paper to protect ""mee.,Cut
I
piece of fibCIJIW
mat
about
one inch larger than the hole and one or more pieces of fiberJiass doth two inches IUJer thoin the hole.
Brush catalyzed resin over hole. lay mat over hole and wet out with catalyzed rain. Use a
~ublnJ
action
with brush. Then apply additional layer or layers of fiberJluI doth to build up patch to the surface of
srrueture,
Wet out each layer thOf'OUlhly with resin.
I. With a squeette or broad knife. work out all air bubblel in the pitch. Work from center to edge.
Pressinl patch finnly apinst the strUcture. AlJow patch to cure for 15
to
10
minutes.
m. As soon
as
the patch
bqins
to set
up. but while still rubbery. take a sharp knife and CUt away
extra cloth and mat. Cut on ouaide
edJe
of fcatherina. Scrip cut
edps
of
ItI'\I.CNt'C.
Do this before cure is
complete.
to
save exna sandi",. Allow patch to cure ovcrrUtht.
n. Ualll dry 80 ,nt sandpaper on a power sander or sandi.. block. smooth patch and blend with
Nrroundiftl surface. Should air pockets appear while
andina.
puncture and fUl with catalyzed resin. A
hYl)odmnic needle may be used to
rill
cavities. Let cure and
raand.
e. Mix catalyzed rain and work into. patch with
r.,.en.
Smooth carefully and work into any
awic¢s.
p. Cover with cellophane and squCClft smooth. AUow to cure completely before removing
cellophane. Let cure and resand.
q. Brush or spray a coat of cawyzed resin
to
sal patch. Sand patch. fmish by priming. "ain sanding
and applying color coat.
NOTE
Brush aDd hands may
be cleaned in solvents such as acetone or
methylethylketone. If solvents ate not available. a srro.. solution of
detClJC1lt and
warer
may be
used
447. Sc:ucrural Repain. Stnacmral repair methods used must be made in accordance with the regulations
S('t
forth in FAA Advisory
Circular 43·13·1. To
wist in
makina repain andlor rcplacemenu. Figures 4-08
thtu ... 13 identifies the type and thickness of various skin mucri&luscd. Never make a skin replacement or
patch plate from material other than the type of the oriJinal skin, or of a different thickness than the
original skin. The rCl'air must be
IS
srronc
IS
the oripnal skin. However, flexibility must be retained so the
surrounding areas will not receive extra
stress.
It may be necessary to
CUt
access holes to make skin rcpain in some areas of the airplane. Refer to
Figure
~l'"
for rypicalaccess holes.
WARNINC
NO access holes are permitted in any control surfaces.
WAJtHINC
The use of patch plates for repairs of all movable tail surfaces is
prohibited. The usc of any
finer
material normally used for repair of
minor dena and/or muerials used for filling the inside of surfaces is also
prohibited on all movable tail surfaces.
STRUCTURE
ISSUED: 8/18/72
1E22
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