Du Pent Teflon® Filled Polyurethane Paint
This paint is a two-component, filled poly -
urethane paint system.
When properly applied, it
provides superior abrasion resistance, chafe and
erosion resistance, toughness, flexibility, gloss, and
color retention. It is applied primarily to the leading
edges of aircraft.
The Du Pont Teflon® filled polyurethane paint is
prepared by thoroughly mixing each of the
components separately.
The base component
(pigmented) should be mixed with a mechanical paint
shaker for 30 minutes. Before you add the hardener,
the pigmented base should be strained through a wire
screen (No. 18 testing sieve). Be sure you crush the
lumps with a mixing stick. One part 10-C-170
hardener (clear) is then slowly added to 1 part 4X203
base component. Stir constantly. Immediately after
you add the hardener, add MIL-T-81772 thinner as
necessary to achieve a viscosity of 20 to 25 seconds
with a No. 2 Zahn cup. The pot life of the mixed
material is 2 hours at a room temperature of 70°F to
75°F (21.1°C to 23.9°C). Do not use the mixed
material over 2 hours after catalyst addition.
Just prior to priming, you should wipe the area
with a lint-free cloth and MIL-T-8 1772 thinner. Use
the “two-rag” technique. Wipe with a solvent-laden
rag and immediately follow it with a dry rag. The use
of a dry tack rag for removing lint is permissible.
This solvent wipe should not be considered as part of
the primer application for the purpose of
time-after-chemical treatment.
After the surfaces have been prepared, you should
apply the epoxy primer.
Do not attempt to apply a
heavy or full-hiding coat. The proper thickness (dry
film of 0.6 to 0.9 mil) is obtained at the point where
the film is wet but retains a translucent appearance.
You should allow the epoxy primer to air dry for a
minimum of 2 hours.
After the primer has cured, apply the first coat of
Du Pont Teflon® filled polyurethane paint as a thin
wet coat approximately 0.6 of an inch thick (tack
coat). Do not dry mist or flood the first coat.
Allow a minimum of 30 minutes for the solvent to
flash off the first coat, and then apply a full wet coat
(1.5 to 2.0 mils). Allow an additional 30 minutes to
cure. Repeat the application process until a topcoat
dry film thickness of 5 to 6 mils is obtained. Allow
the complete system to cure overnight. The full cure
takes 7 to 10 days at 70°F to 75°F (21.1°C to 23.9°C).
Epoxy-Polyamide MIL-C-22750
Epoxy-polyamide is an alternate material for
aliphatic polyurethane. The epoxy-polyamide
topcoat is a two-component kit. One part of the kit
contains a pigmented component; the other part of the
kit contains clear resin. The pigmented component
and clear resin are mixed in a one-to-one ratio prior to
use. The local air pollution regulations, mixing,
thinning and application instructions for
MIL-C-22750 epoxy-polyamide topcoat are identical
to those for aliphatic polyurethane with the following
exceptions:
The stand time after mixing is
30 minutes, and it should be thinned with
MIL-T-81772 (preferred) or MIL-T-19544 (alternate).
You should allow the thinned paint to stand for a
minimum of 30 minutes before it is used. The total
mixing, thinning, and stand time should not exceed
1 1/2 hours. The time between coats should be about
30 minutes, and the temperature during application
should not be less than 50°F. The application of
epoxy-polyamide is not limited by relative humidity
or high temperatures.
Acrylic Nitrocellulose Lacquer
MIL-L-19537 (gloss) and MIL-L-19538
(camouflage) acrylic nitrocellulose lacquers are the
preferred topcoat materials for aircraft markings and
propeller safety stripes.
MIL-L-19538 is also used
for paint touchup of avionic components and
instruments.
You may thin MIL-L-19537 or MIL-L-19538 to a
spraying viscosity by thoroughly mixing 1 part of
lacquer with approximately 1 part of MIL-T-19544
thinner (preferred) or MIL-T-81772 thinner
(alternate).
The exact thinning ratio should be
determined by the user and adjusted to the
temperature, relative humidity, and spraying
equipment. Acrylic nitrocellulose lacquer that has
been thinned to spraying viscosity should be applied
to a thickness of 1 to 2 mils. Acrylic nitrocellulose
lacquer with an aerosol container may require three to
four coats to cover the primer. A 5- to 10-minute
air-drying interval should be allowed between coats.
Apply only the minimum thickness required to cover
the primer coat and allow 1 hour to dry.
14-34
