TM 1-1500-204-23-11
(2) Hand Routing Method. Hand routing oper-
using a hand sand method. Deeper damage will
ations can be performed without a template, using
require a sanding disc (80 to 120 grit) attached to a
either a 0 degree or 90 degree router motor. Remain
die grinder or a small dual action sander. Sand care-
1/8 inch inside the damage outline while routing.
fully as the material is removed quickly. Care must be
Then, inish sand the damage cleanup hole edge to
taken to not remove excess material beyond the max-
the damage outline. Use a 90 degree router motor,
imum damaged depth. Since multilevel delaminations
a sanding drum with an 80 grit abrasive sleeve or a
may be present, reinspect the area in question using
1.0 inch diameter diamond coated router bit for inish
NDI after the damage is removed. If delaminations
sanding of the damage cleanup hole edge.
are present in the skin below the original damage
area, remove them by sanding and reinspect using
NDI. Taper the edge of the partial thickness damage
c. Partial Thickness Damage. Partial thickness
removal area to provide a smooth transition between
damage (scratches, skin gouges, small near surface
the damage depth and the outer skin surface. Refer
delamination damage, and other similar types of dam-
to the system speciic technical manual for the proper
age that penetrate partially through the skin thickness)
taper to use for blending out the damage. The length
must be sanded down to undamaged material. After
of the taper should be 10 times the damage depth
determining the damage depth and damage outline,
sand down to the damage depth. Very shallow dam-
age can be removed by blending out the damage