MOONEY INTERNATIONAL CORPORATION
M20V SERVICE AND MAINTENANCE MANUAL
Page
Date
20
MAR 2017
Rev Date
2. Remove damaged areas.
A. Cut back to 1” beyond visible damage, taking
care not to cause delamination of the remaining com-
posite laminate.
B. Remove all paint and other coatings from any
surfaces that are in the repair area.
C. Lightly sand and abrade the surface of the part
to uncover the base laminate to provide a bonding sur-
face for the wet laminations.
-NOTE-
Perform repairs from the non- tooled side of the
laminate when possible.
3. Scarf edges of laminate at a shallow angle. When
possible, the length of scarf should be equal to ½”multi-
plied by the number of plies in the laminate. If not pos-
sible, the repair plies will extend beyond the scarfed
surface and onto the “bag side” of the part.
4. Thoroughly clean surfaces of part with acetone or
similar solvent. Allow to evaporate dry.
5. Prepare layup surface.
-NOTE-
Repair the damaged part in the original tool when
possible.
A. If surface to be repaired is flat, a suitably pre-
pared sheet of metal can be used as a temporary tool.
B. If the surface to be repaired is a single curvature
surface, a thin sheet of suitably prepared metal can be
used as a temporary tool.
C. If the surface to be repaired is a compound
curvature, a patch tool can be created by either lamin-
ating over the same surface on another aircraft or by
laminating over a dummy part laid up in the original tool-
ing.
6. Prepare the tool.
A. Prepare the tool surface in the usual manner.
B. Clean off the surface of the tool.
C. Read the manufacturer’s data sheet for the re-
lease agent and/or SPS 300-2.
D. Apply a coat of release agent (Frekote or simil-
ar) and leave to harden for the time duration stated on
the manufacturer’s data sheet and/or to SPS 300-2.
E. Polish the surface until smooth.
F. Repeat the application and polishing procedures
until the appropriate number of coatings have been ap-
plied.
G. Cover with a cloth or plastic to prevent contam-
inants from falling on the tool surface.
H. Allow the release agent to fully harden.
7. Re-fit the part back in the original tool or locate the
temporary patch tool on the tool side of the part in the
repair area. If necessary, attach the patch tool in place
using clamps, tape, or temporary rivets.
8. Mix the resin according to the manufacturer’s data
sheet for proper mix ratio, the effective working (pot)
life, the normal cure temperature/cure parameters, and
other instructions.
9. Apply the material.
A. Clean the plate glass “wet-out surface” with
acetone and allow to evaporate until dry.
B. Measure size and shape of damaged area. A
template may be useful if the shape is irregular.
C. Cut the first repair ply ½” larger at all edges than
the damaged area.
D. Cut successive repair ply shapes from dry fiber,
each one being ½” larger at all edges than the preced-
ing ply.
E. Vary the direction of the fiber orientation in the
blanks, alternating 0/90 and 45.
F. Place one dry fiber on the plate glass surface.
G. Wet the first ply with resin, ensuring full resin
coverage and no dry areas. Aim to achieve 40% resin
content by weight.
H. Peel off the wet ply from the glass and transfer it
to the part. Place the wet ply over the damaged area en-
suring an adequate and even overlap at all edges with
theexistingpanel.
I. Press down the ply onto the edges of the dam-
aged panel and the surface of the temporary tool using
a brush, a spatula, or a roller. Ensure that the ply is in full
contact with the existing panel and the temporary tool
surface and that the plies are well pressed together
during ply application.
J. Work the resin through the fibers to ensure no
dry areas remain.
K. Repeat the application process alternating ply
orientations and overlap distances until repair is of
equal thickness to or one ply thicker than the base lam-
inate.
L. Cover the repaired area with nylon peel ply.
M. If possible, apply a vacuum bag to the repaired
area and evacuate the air for increased consolidation.
This may require envelope bagging (bagging both
sides together) to attain vacuum integrity.
10. Leave assembly to cure for the duration stated in
the resin manufacturer’s specs. Cure time may vary as
curing process is accelerated at elevated temperatures.
51-15-03 - CORED PANELS
If damage is only through one side of the laminate, a re-
pair can be facilitated without the need of disturbing the
other skin. Trim back the damaged skin, scarf the
edges, fill to core until flush with surrounding core sur-
face, then apply the laminate repair as described
above. After cure, sand the outer surface until smooth.
If damage in the cored panel affects both inner and out-
er surfaces, either by penetration or distortion of the
51-15-03
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