Technical data
Class C1 Barium chromate based corrosion inhibi-
tors
Class C2 Strontium chromate based corrosion in-
hibitors.
Class N Non-chromate based corrosion inhibitors.
Class N shall not be substituted for Class C,
unless authorization is given by the engineer-
ing authority for the system or item on
which the primer is used.
6.12.2.2 Uses. A primer for MIL-PRF-85285 polyure-
thane topcoat for the exterior of aircraft, components, and
other aerospace equipment, and as a stand alone primer on
interior surfaces of aircraft and components.
6.12.2.3 Mixing. Thoroughly agitate components (Ep-
oxy Resin Base Component A and Polyamide and/or amine
resin curing agent Component B) preferably with a mechani-
cal shaker prior to mixing and if required pour into separate
measuring or metering containers. Using manufacturer’s
directions, mix proper volumes of the components A and B by
pouring B into A and thoroughly agitating. Best mixing
results can be achieved with a mechanical shaker. Mix only
materials from the same manufacturer, and do not mix more
material than can be used in a 4-hour period. After mixing,
allow the primer to stand 30 minutes before applying. This
primer must be agitated continuously during spraying appli-
cations to prevent settlement of pigment and ensure unifor-
mity of color. If in-line or in-head proportioning equipment is
used to mix base and catalyst (curing agent) as the paint is
being used, a 30-minute dwell time is not required before
application.
6.12.2.4 Thinning.
• MIL-T-81772 is flammable and moderately
toxic to eyes, skin, and respiratory tract. Eye
and skin protection required.
• Parachlorobenzotrifluoride (PCBTF), NSN
6850-01-399-0676, is combustible and an ir-
ritant to eyes, skin, and respiratory tract. Eye
and skin protection required. Disposable 8 mil
nitrile gloves, splash goggles, tyvek/cloth cov-
eralls are the recommended PPE. Use in well
ventilated areas.
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.
The viscosity of the unthinned primer may range up to a
maximum of 40 seconds in a No. 4 Ford Cup (56 seconds in
a No. 2 Zahn Cup). Strain the primer through clean cheese-
cloth, per CCC-C-440, Type I, Class 2 or a commercial paint
strainer. When required, adjust the viscosity by thinning to a
viscosity of 8 to 19 seconds in a No. 4 Ford Cup (17 to 23
seconds in a No. 2 Zahn Cup). Use thinner per MIL-T-81772
Type II or PCBTF, NSN 6850-01-399-0676. Add MIL-T-
81772, Type II thinner as required to achieve the viscosity
range above. In areas where air quality regulations restrict
volatile emissions, thin with PCBTF using up to 10% by
volume as a recommended maximum for reduction of vis-
cosity.
6.12.2.5 Application. Apply one coat of primer to a dry
film thickness of 0.6 to 0.9 mils, per Table 5-2. Allow a
minimum of five hours air dry at 75° F and ten hours at 60°
F before application of topcoat. After 8 hours at 75° F, solvent
wipe per Chapter 3 to reactivate before topcoating. Since this
epoxy primer has a very high solids content, cross coating
may not be required; and the spray gun must be kept moving
to prevent excessive film build-up with subsequent reduction
of adhesion. Apply a topcoat within 24 hours of primer
application. After 24 hours, scuff sand the entire primed
surface with A-A-58054, Type I, Grade A abrasive mat and
solvent wipe the area per Chapter 3 prior to topcoating.
Discard any of this primer mixed for longer than the four
hours pot life at 75° F. Higher or lower temperatures shorten
or lengthen the pot life proportionally.
6.12.2.6 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.
6.12.3 Primer Coating, Epoxy, VOC Complaint,
Chemical and Solvent Resistant, MIL-PRF-85582.
TO 1-1-8
Change 3 6-7