Technical data

Care should be taken when cutting and trimming
of the barrier/tape to prevent damage to any
transparent plastic and glass surfaces.
NOTE
For general large area masking use either Type I
or Type II. For operations involving sharp, fine
line color separation such as aircraft markings
and two tone gloss color schemes, use Type III
tape only. This tape is designed to prevent edge
bleeding and is more flexible for masking shapes,
curves, etc.
a. Cover small or irregular shaped parts with tape alone.
Use pressure-sensitive masking tape conforming to SAE
AMS-T-21595 (formerly MIL-T-21595), Types I and II.
b. In repetitive spraying of the same or similar structures it
is advisable to have available predesigned bandages,
socks, etc., of barrier paper or cloth. Locally manufac-
tured foam plugs or inserts may be used to protect
aircraft inlet areas (e.g., scoops, air intakes, engine
intakes, etc.) from painting as a replacement for mask-
ing and barrier paper. It is recommended that MIL-PRF-
26514, protective ion material, be used in the making of
foam plugs/inserts. One side of the plug should be
covered in replaceable plastic or barrier material for
easy cleanup.
NOTE
Care should be taken to ensure that paint is not
applied to certain surfaces where paint will inter-
fere with a function. The following should be
masked or otherwise protected during painting:
Machined surfaces that move with respect each
other such as threads, bearing contacts and gear
teeth; electrical parts, such as contacts, relays,
insulators, sockets, plugs, connectors, wiring and
terminals; plastic and rubber (natural and syn-
thetic) mounts, spacers, etc., and lubrication fit-
tings, cups, oil holes, etc.
c. Avoid using tape in such a way as to leave a paint edge
on aerodynamic surface unless feathering by sanding
can safely be done.
d. Use only approved masking tapes in varying widths
required by the job. A complex curved area is better
masked initially at the paint edges with narrow (1/4 or
1/2 inch) tape. Wider tape may then be applied over the
narrow, if required.
e. Use only approved masking paper for large area mask-
ing. Coating solvents may dissolve and deposit printing
ink from newspapers, etc., on surface of the area being
masked.
f. When spray painting, mask or cover surfaces at a
distance from the area being painted which might
receive overspray or paint drift.
g. Masking tapes should be removed as soon as possible
after coating application to allow edges of coating to
heal and draw down as much as possible.
h. Press tape firmly when applying it to prevent paint
bleeding under it by capillary action.
3.1.27 Tack Ragging.
Exercise extreme caution in applying protective
finishes to parts and equipment which may con-
tact propellants directly or by accidental spillage.
Critical areas may have to be masked. The
guidance of applicable equipment technical
manuals or engineering drawings shall be fol-
lowed concerning use of protective finishes on
parts or equipment used in or near propellant
storage and transfer systems.
Commercial rental wiping cloths, laundered shop
cloths, or disposable fiber or chemically treated
paper wiping materials shall not be used.
To ensure that all primed surfaces are free from foreign
matter, they should be tack-ragged immediately before ap-
plying the topcoat. Do not tack-rag an entire large structure at
one time. Each area to be painted should be tack-ragged
immediately prior to the application of finishing material to
that area. Surfaces are gently wiped with the tack-rag,
removing accumulations of dust and other foreign matter.
One form of tack rag in common use to A-A-2522, Grade A,
Color 1 dampened with an approved solvent per Table 3-2.
Other commercially available forms of tack rag which are
designed for the purpose of removing surface contamination
from an area receiving paint may also be used. Do not use a
tack-rag to clean more than 10 square feet at a time to prevent
spreading any contaminants on the rag over a large surface.
TO 1-1-8
3-17/(3-18 blank)