design will be used under machine screws, countersunk
fasteners, boltheads, and nuts that would otherwise
h. Masking. Masking of specific areas is required in
painting operations on large assemblies or structures
either for protective reasons, as in the precautionary
note below, or for purposes of delineation. Masking
conditions are as follows:
Care should be taken to ensure that paint
is not applied to certain surfaces where
paint will interfere with a function. The
following should be masked or otherwise
surfaces that move with respect to each
other such as threads, slip rods, bearing
contacts and gear teeth; electrical parts,
such as contacts, relays, insulators,
sockets, plugs, connector, wiring and
terminals; plastic and rubber (natural and
synthetic) mounts, spacers, etc., and
lubrication fittings, cups, oil holes, etc.
(1) Mask areas such as windows large openings,
etc., with combinations of barrier papers:
usually a treated paper which is oil
and moisture resistant.
usually a laminated toil and cloth or
foil and paper with good water vapor
Both types above are heat sealable.
Crepe backed paper masking tape, MIL-
T-21595, Type I.
(2) Cover small or irregularly shaped parts with tape
(3) In repetitive spraying of the same or similar
structures, it is advisable to have available predesign
bandages, socks, etc., of barrier paper or cloth.
(4) Avoid using tape in such a way as to leave a
paint edge on surfaces unless feathering by sanding can
be done safely.
(5) Use only approved masking tapes in varying
widths required by the job. A complex or curved area is
better masked initially at the paint edges with nanow
(1/2 inch) tape. Wider tape may then be applied over
the narrow, if required.
(6) Use only approved masking paper for large area
masking. Coating solvents may dissolve and deposit
printing ink from newspapers, etc., on the surface of the
area being masked.
(7) When spray painting, mask or cover surfaces at
a distance from the area being painted which might
receive overspray or paint drift.
(8) Masking tapes should be removed as soon as
possible after coating application.
(9) Press tape firmly at the masking edge when
applying it to prevent paint bleeding under it by capillary
i. Application Equipment. Application systems and
components of application equipment are described in
the following paragraphs.
(1) Application systems. The application equipment
plays a key role in the overall success of painting
equipment and components. Selection of application
systems and care thereafter are essential (robotics) or a
manual type. No description or details are provided
equipment manufacturers and local conditions. Each
manufacturer's instructions and other details must be
consulted. Special consideration should be given
equipment with which plural components are to be
applied. Problems may be encountered, i.e., required
accuracy of mixtures, pot life of mixtures and effects
resulting from non-adherence to prescribed application
(2) Components of application equipment. The
following paragraphs describe application equipment.
(a) Automated systems (robots). Such systems
include, but are not limited to, metering and mixing
equipment, air compressors, air cleaners, electrostatic
generators, spray booths, feed lines and tanks,
regulators, and computerized automated components.