Technical data

13773-001
51-20
Page 28 30 Nov 2000
(2) Determine type of damage:
(a) Laminate Only, Minor Core, Major Core, or Sandwich Penetration. (Refer to 51-10)
(3) Expose Damage and Prepare Repair Area
(a) Cover the damaged area with plastic sheet and seal the edges with tape to prevent mois-
ture from penetrating the composite laminate and core.
(b) Clean the area surrounding the damage with hot soapy water. Rinse repair area with clean
water and dry. When dry, remove plastic sheet from damaged area.
Note: Moisten cloth with cleaning solvent. Never pour solvent directly onto lami-
nate, allowing laminate to soak up cleaning solvent.
(c) Solvent clean the damaged area with isopropyl alcohol and dry with a clean cloth. (Refer
to 20-30)
(d) Mask off the surrounding surfaces to protect them from spilled resin and scratches.
CAUTION: Never use grease pencils or china markers to mark visible damage. The
surface being repaired will be contaminated from the residue left behind.
(e) Inspect damage, mark out all visible damage. Layout an oval or circular (approximate)
perimeter that includes all observed damage. If possible, examine from the back side.
(f) Mark the 0° axis for reference. This line will be used for positioning the repair plies. (See
Figure 51-204)
(g) Carefully trim away damaged laminate using a small angle grinder, with 80-grit or similar
disk, to taper the edge of the damaged laminate at approximately a 1:50 taper (taper
length is 50 times the thickness of the laminate).
Note: If ply lay-up information (ply lay-up and ply orientation) is not available,
retain a section of the damaged laminate, this may be used to determine
number of plies and fiber orientation. Mark a reference line on the retained
section to maintain orientation.
(h) Check for separation of laminate from the core. If required, continue to sand back until all
separated laminate is removed. Continue tapering back the laminate until all damage is
removed. Remove paint and primer as required.
Note: When repairing an inner laminate or a pure laminate section, do not taper
the laminate edge until the backing plate has been attached. If core or inner
laminate requires repair, refer to the section entitled “Repair Techniques”.
(Refer to 51-20)
CAUTION: Do not use a grinder when repairing an inner laminate or a pure laminate
section, as it will gouge the laminate creating more damage.
(i) Once the extent of damage is determined, remove surface coats (paint, primer, and body
filler) from the surrounding area of damage. This can be done either by hand, or by using
a multi-action sander. Multi-Action orbital type sanders or simple hand-sanding are the
preferred methods of paint removal.