Technical data
material thoroughly following manufacturer’s instructions.
Do not mix more material than can be used in four hours.
NOTE
Some materials are mixed in a three to one by
volume ratio.
6.12.4.4 Thinning.
• MIL-T-81772 is flammable and moderately
toxic to eyes, skin, and respiratory tract. Eye
and skin protection required.
• PCBTF, NSN 6850-01-399-0676, is combus-
tible and an irritant to eyes, skin, and respira-
tory tract. Eye and skin protection required.
Disposable 8 mil nitrile gloves, splash
goggles, tyvek/cloth coveralls are the recom-
mended PPE. Use in well ventilated areas.
• All thinners used with this coating must be
“urethane grade” with a water content of less
than 0.05% by weight.
• In areas where air quality regulations restrict
volatile emissions, do not add thinner MIL-T-
81772 to the primer coating as that addition
may raise the VOC content to greater than 340
g/L (2.8 lbs/gal).
NOTE
PCBTF, NSN 6850-01-399-0676, is exempt as a
VOC or HAP by the EPA and by 48 states and
will not change compliance of high solids coat-
ings to air quality regulations.
Thinning of this primer is not required, as viscosity as
manufactured should be correct for spray application. If
thinning is done, it shall be with MIL-T-81772, Type I or
PCBTF, NSN 6850-01-399-0676. Use thinner in the least
quantity necessary to get the proper viscosity. The application
viscosity will be approximately 14 seconds in a No. 4 Ford
Cup (20 seconds in a No. 2 Zahn Cup).
6.12.4.5 Application. After thoroughly cleaning, sur-
face treating and solvent cleaning the surface to be primed per
Chapter 3, apply one coat of primer to a dry film thickness of
1.0 to 1.5 mils (1.7 to 2.5 mils wet film) per Table 5-2. This
primer will not adhere to an improperly prepared or contami-
nated surface. Allow a minimum of two hours air dry at 75°
F and 50% relative humidity or four hours at 60° F and 50%
relative humidity before application of topcoat. The coating
must be applied in a relative humidity range of 30% to 80%.
If humidity is below 30%, add moisture to the air by wetting
the floor of the painting area or by equivalent methods. After
8 hours at 75° F, solvent wipe per Chapter 3 to reactivate
before topcoating. If the primer is not topcoated within 24
hours, reactivate the primer surface by light sanding or
scuffing with A-A-58054, Type I, Grade A abrasive mat and
solvent wiping per Chapter 3. Discard any primer mixed
longer than four hours.
6.12.4.6 Drying Time. The times given here are for 75°
F at 50% relative humidity. Lower temperatures and higher
relative humidity will increase these drying times while
higher temperatures and lower relative humidity will decrease
these drying times. Tack free - 5 hours; Dry hard - 8 hours;
Full cure - 48 hours.
6.12.5 Primer Coating, Elastomeric, Polysulfide Cor-
rosion Inhibiting, PR-1432GV.
PR-1432GV is moderately toxic to eyes, skin,
and respiratory tract. Eye and skin protection
required. Consult Bioenvironmental Engineering
to determine need for respiratory and ventilation
requirements.
6.12.5.1 Characteristics. This is a two component,
polysulfide primer, particularly formulated for its corrosion
resistance and flexibility. It is a superior material for protec-
tion of relatively flexible aircraft structures as it does not
crack or peel away from fasteners in highly stressed areas,
and it will not crack, peel, or rupture from lap and butt joints.
The physical properties of this primer on large flexible
aircraft structures will increase the longevity of the paint
system as well as decrease maintenance and corrosion rework
during the life cycle of the coating system.
6.12.5.2 Uses. As a primer for MIL-PRF-85285 poly-
urethane topcoat on aircraft exterior surfaces. The Weapon
System Manager shall specify when this primer is to be used.
6.12.5.3 Mixing. Adequate curing of sealant and sealant
based coatings depend on proper and controlled component
mixing by weight. This ensures that the component ratio is as
close as possible to that specified by the manufacture. When
mixing partial kits, an accurate scale is required that will
weigh up to 2.6 kilograms to the nearest 0.1 of a gram. One
scale meeting these requirements is the Triple Beam 760-W
Balance made by Paul N. Gardner Co., Inc.; 316 N.E. First
St.; Pompano Beach FL 33060. Mix the base compound and
(component A) and the accelerator (component B) in the
TO 1-1-8
6-9