Technical data
corrosion rework areas on clad and unclad aluminum alloys.
This specification covers the preparation and application of
chemical conversion materials, and film formation or consis-
tency. These coatings are not as abrasion-resistant as anod-
ized coatings conforming to specification MIL-A-8625, even
though they do provide an effective means for re-establishing
the corrosion resistance of mechanically damaged anodic
coatings in the field. Specification MIL-DTL-5541 covers
two classes of films as follows:
3.1.15.1.1 Class 1A - For maximum protection against
corrosion.
3.1.15.1.2 Class 3 - For protection against corrosion
where low electrical resistance is required.
3.1.15.2 Specification MIL-C-81706/MIL-DTL-81706,
Chemical Conversion Materials for Coating Aluminum and
Aluminum Alloys, covers the chemicals used in the formation
of conversion coatings. These are available under this speci-
fication in three forms:
Form I - Concentrated Liquid
Form II - Powder
Form III - Premixed liquid (ready for use touch-up
brush application)
3.1.15.3 Each form of MIL-C-81706/MIL-DTL-81706
can be applied by spray, brush or immersion. Materials for
Class 1A chemical films are available in iridescent yellow or
light brown, or dyed in specific colors. The prepaint treatment
of aircraft surfaces prior to repainting will be accomplished
using specification MIL-DTL-5541, Class 1A coatings, using
specification MIL-C-81706/MIL-DTL-81706, color irides-
cent yellow.
3.1.16 Touch-Up of Damaged Aluminum Surface
Treatment MIL-DTL-5541. The touch-up of damaged
MIL-DTL-5541 coatings due to maintenance or surface
preparation for maintenance painting can be accomplished
using one of three methods:
3.1.16.1 MIL-C-81706/MIL-DTL-81706, mixed (if re-
quired) per Paragraph 3.1.18 and applying to affected areas
per Paragraph 3.1.19.
3.1.16.2 MIL-C-81706/MIL-DTL-81706, mixed (if re-
quired) per Paragraph 3.1.18 and applying to affected areas
per the “NO-RINSE PROCESS” in Paragraph 3.1.17.
3.1.16.3 Touch-N-Prep™ (TNP) Pens (Alodine 1132).
NSN 8030-01-460-0246, for minor repair of damaged MIL-
DTL-5541 chemical conversion coatings on aluminum alloys
can also be accomplished by applying Alodine 1132 using the
TNP pens. These pens also conform to MIL-C-81706/MIL-
DTL-81706, Class 1A, Form VI, Method D. The solution
applied with TNP pens doesn’t require rinsing or wiping off
following application, thus minimizing hazardous waste gen-
eration. Empty pens can be returned to manufacturer for
disposal. However, check with Bioenvironmental Engineer-
ing and Environmental Management for proper disposal of
used applicators. To use the TNP pen, remove the cap and
charge the tip by pressing the tip against a flat surface for 10
to 15 seconds. The conversion coating solution will saturate
the tip. Do not oversaturate the tip. Refresh solution often
during use in a similar fashion.
NOTE
Acrylic tip of TNP pen can be modified or altered
to form any shape to allow touching up hard to
reach areas.
a. It is necessary to ensure the surface to be treated is
thoroughly cleaned before application. Immediately fol-
lowing cleaning, use the TNP pen to apply a chemical
conversion coating solution in overlapping parallel
strokes. Do not over apply the solution which would
allow puddles, drips, or runs to form.
b. Apply one coat of solution and allow coating to dry for
5-10 minutes before next application.
c. Apply a second coat perpendicular to the first coat and
allow it to dry. The treated surface does not require
rinsing or wiping off, and it can be air dried at ambient
temperature or force air dried with hot air. Once
completely dried, the coating is ready for priming and/or
painting.
d. Use of TNP pen will be limited to 1 square foot.
3.1.16.4 After processing, if bare surface areas still exist
repeat steps a through c. Also, if the treated surface does not
turn to an iridescent yellow color shortly following applica-
tion, re-clean the surface and reapply per steps a through c.
3.1.17 “No-Rinse Process” For Surface Treatment of
Aluminum. This process is for applying conversion coat-
ing using a “wipe-on and blot-off” method. This procedure
can be used in order to minimize hazardous waste water
generated from the application of MIL-C-81706/MIL-DTL-
81706 solutions. This process is for use on repaired areas and
where coatings have been damaged or removed. Application
of this process is not to exceed 4 sq. ft. per occurrence.
a. Apply corrosion removal solution (MIL-C-38334/SAE
AMS-1640, diluted with an equal amount of water) by
sponging, brushing, or wiping. The solution is more
effective if applied warm (130° F ± 10° F), followed by
vigorous agitation with a non-metallic, acid-resistant
brush or aluminum-oxide-abrasive, nylon mat (A-A-
58054, Type I, Grade A), or scouring pads. Applying the
solution with a circular motion will disturb the surface
film and assure proper coverage. Allow the solution to
remain on the surface approximately 12 minutes. Keep
the surface wet during the entire 12 minutes. Rinse,
using a clean cloth dampened with cold potable water.
After rinsing with cold water, allow the water to
evaporate until a thin film of water exists on the surface.
Corroded areas identified for treatment during the pre-
TO 1-1-8
Change 3 3-9