Technical data

3.1.20 Alternate Surface Preparations For Aluminum
Surfaces (PreKote SP).
PreKote SP is for exterior mold line applications
only.
NOTE
• PreKote SP requires specific System Program
Office (SPO) approval prior to use.
• PreKote SP will only be used with chromated
primers.
• PreKote SP is not a direct drop-in replacement
for current chromated conversion coating pro-
cesses. Unlike the application process for
MIL-DTL-5541/MIL-C-81706/MIL-DTL-
81706, which produces a visible indication
that the chromate conversion film has formed,
PreKote SP does not provide any type of
visible indicators. Therefore, it is absolutely
critical that all steps of the PreKote SP appli-
cation process be precisely followed.
PreKote SP is a non-chromic, non-hazardous and non-toxic
alternative to chromate conversion coatings for surface paint-
ing preparation operations. The PreKote SP formulation is a
non-chromic alkali soap with a saline adhesion promoter and
inorganic inhibitor package. The PreKote SP application
cleans the surface and deposits a very thin layer of adhesion-
promoting organic molecules on the surface of the substrate.
3.1.20.1 Surface Preparation. Preparation for aircraft
cleaning shall be accomplished in accordance with TO
1-1-691 and any weapon system specific cleaning instruc-
tions. Rinse exterior of aircraft with hot water (100-120°
F/38-49° C) to remove any residue left in seams or on
surface.
Finish system removal using motor driven abra-
sives may generate airborne particles and toxic
dust, which may injure personnel and create a
possible dust explosion. All aerospace and mo-
torized ground equipment shall be properly elec-
trically grounded. Personnel shall wear dust par-
ticle masks, goggles, gloves and long sleeved
shirts when using motor driven abrasives. Con-
sult Bioenvironmental Engineering Services for
respiratory and ventilation requirements.
Avoid excessive pressure or repeated passing
over the same area while sanding. Excess sanding
can cause damage to the surface of the aircraft.
NOTE
Some residual amounts of old coating system
may be left after stripping (i.e., fastener heads,
seams, hinges, surface porosity, etc.). These areas
are acceptable as long as they are feathered into
the surrounding surface.
a. Lightly sand aircraft and feather sand the rough areas of
the aircraft with 240-grit sandpaper.
b. Remove all tape adhesive residue using solvent, dena-
tured alcohol or isopropyl alcohol.
NOTE
If rinse facilities are not available, solvent wipe
using denatured (O-E-760/MIL-A-6090, Type
III) or isopropyl (TT-I-735) alcohol on clean
lint-free cotton rags (CID A-A-59323) is an
acceptable substitute process.
3.1.21 Application of PreKote SP.
Personnel shall wear full rain gear, face shield
and rubber gloves to remain dry during the
application of PreKote SP.
PreKote SP shall only be applied when tempera-
ture is maintained between 65° F/18 C and 110°
F/43 C, and humidity is between 10% and 90%.
Coating system failure may result if these condi-
tions are not met.
a. Mask aircraft IAW the any weapons system require-
ments for preparation of surfaces prior to painting.
PreKote SP SP may be applied by pressure sprayer,
spray bottle or fluid feed attached to sander. Use 180-grit
scrub pads (A-A-58054 Type 1, Class 1, Grade B
abrasive mat) attached to pneumatic sander to agitate.
TO 1-1-8
Change 3 3-13