MOONEY INTERNATIONAL CORPORATION
M20V SERVICE AND MAINTENANCE MANUAL
Page
Date
19
MAR 2017
Rev Date
51-15-00 - FIBERGLASS LAMINATES, REPAIR
PROCEDURES
Despite the fact that fiberglass laminates are designed
to withstand considerable abuse, occasional repairs
will be necessary. It is difficult to cover all the various
repair techniques due to such limiting factors as acces-
sibility and the extent of damage. The following outlines
those steps which are used to make repairs of the more
common type damage to a fiberglass laminate.
1. Materials used for repairs shall be as specified and
compatible with the basic resin used in the fiberglass
laminate (Figure 51- 25).
Resin
Aerospace Adhesive EA934
Part A
Catalyst Aerospace Adhesive EA934
Part B
Hysol Division
The Dexter Corporation
Alternates
Resin Epoxical #606 Patching Adhesive
Resin
Catalyst Epoxical #606 Patching Adhesive
Hardener
United States Gypsum
OR
Resin Ren Epoxy CG 1304
Catalyst Ren Hardener CG 1304
Ren Plastics Co.
Lansing, Michigan
REPAIR MATERIALS
FIGURE 51- 25
Fire retardation - Antimony Trioxide for fire retardation
(5% minimum; 10% maximum by Weight of Resin Con-
tent) must be added to the base resin (cowling and air
intake duct assemblies).
The manufacturer’s bulletins shall be followed for all
mixing ratios and preparation prior to application.
2. General.
A. The configuration of repairs is shown for flat sur-
face areas; for simplicity, however, the same tech-
niques can be used for contoured surfaces. Contoured
repairs will require additional considerations and the
proper shaping of the backup plates used for clamping
the laminates together during the curing cycle.
B. The degree of laminate chamfer and size will
vary based on accessibility, shape of part and the ex-
tent of damage.
51-15-01 - CRACKS, IN SURFACE AREAS
1. Stop drills all cracks per standard aircraft proce-
dure.
2. Remove any loose particles and frayed fiberglass
strands from the cracked portion.
3. Prepare surface for repair as shown in Figure
51- 27, Figure 51- 28, and Figure 51- 29.
4. Prior to continuing the repair, all surfaces in the
area of the repair must be cleaned of all contaminates
by wiping the area with a clean cloth saturated with
Methyl- Ethyl- Ketone.
-CAUTION-
Methyl Ethyl Ketone (M.E.K.) is a flammable
liquid and should be used with proper ven-
tilation and the prescribed safety equipment.
-CAUTION-
Fiberglass components are attacked and dete-
riorated by the following products: K etone, ali-
phatic esters, chlorinated hydrocarbons, and
slightly softened by aromatic hydrocarbons.
51-15-02 - NON- STRUCTURAL REPAIR,
FIBERGLASS LAMINATE
Epoxy Resin
Two part toughened epoxy resin
(CYTEC MTM45- 1 or similar)
Glass Fiber
Material
Of similar areal weight and
weave NMS 451/4 uses 7781,
0.010” thick
Vacuum Bag Peel ply, perforated ply and
breather cloth, etc
Vacuum Bag
Sealant Tape
Any compatible sealant tape
Release Agent Frekote 700-NC release agent
or similar
Filler Any compatible filler
Sheet of Plate
Glass
Of suitable size or a similar
smooth surface for wetting out
the plies
Miscellaneous Tool cleaner, acetone, brushes,
spatulas, rollers, mixing cups,
stirrers, latex gloves, lint-free
cloths, etc.
REPAIR MATERIALS, NON- STRUCTURAL
FIGURE 51- 26
1. Assess the extent of the damage.
A. Perform a visual inspection.
B. Perform a “coin tap” test by tapping the edge of a
coin on the panel and listening to the sound that is
made while progressively moving across the damaged
area. Delaminated plies will produce a lower-pitched,
hollow sound. In-tact plies produce a higher- pitched
sound.
51-15-00
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