TM 1-1500-204-23-1 (a) Inspect panels for internal deliminations You can find the location and size of any internal   delamination   by   lightly   tapping   the   fiberglass reinforced plastic backing using a coin or small hammer. NOTE ·    The tapping sound will be a clear metallic    ring    over    well-bonded areas, and a dull thudding sound over   delaminated   areas.      Trace the   outline   of   and   delaminated area    with    chalk    for    reference during repair. ·    Internal    delamination    up    to    4 inches in diameter are acceptable without repair. Although a ballistic  degradation  does  occur from a delamination of fiberglass plies,     excessive     resin     in     the delamination cavity has a greater degrading effect. Excessive resin  promotes  ballistic  shearing as   opposed   to   bulging   of   the fiberglass backing.  Do not repair armor   panels   with   any   internal delamination     in     excess     of     4 inches  in  diameter  or  with  more than one area of internal delamination. (b) Repair    internal    delaminations    by using  a  resign  and  curing  agent  mixed  as  specified  in paragraph 9-23d(3)(c). (c) Drill a small hole at each end of the void (marked during inspection). (d) Slowly  inject  resin  using  a  syringe until  void  is  filled  and  epoxy  discharges  from  opposite hole.  See figure 9-38 Additional holes may be needed if air entrapment occurs when injecting the resin. (e) Attach   metal   clamps   or   brace   the panel   in   a   fixture   to   apply   the   required   high   contact pressure  to  seal  the  filled  area.    Use  care  to  distribute the contact pressure to prevent damage to the ceramic tile. (f) Cure the panel at room temperature for five days. NOTE ·    Maintenance activities desiring to repair internal delaminations must have the required tools and fixtures to assure a tight relamination. ·    If the delamination cavity is filled with  resin  without  rebonding  the fiberglass   plies,   the   repair   will have reduced ballistic protection. (5) Repair    and    inspection    of    minor scars  and  fraying  of  backing.    Repair  and  inspection procedures are as follows: (a)    Inspect    panel    for    scars    or surface  abrasion,  and  for  fraying  along  edges  of  the backing. NOTE After   a   time,   fraying   will   occur   on some  permanent,  exposed  edges  of the  panel  having  no  protective  edge molding.        You    may    repair    frayed edges,   but   only   to   edges   normally having no protective molding. Figure 9-38.  Delaminated Repair 9-54