General Specifications - Appendix 6
AND CEMENTING VESSELS
OF THE UNITED STATES NAVY
Edition of June 1943
Chapter 2. - Metal
Preparation and Priming of Surfaces
A prerequisite to acceptable paint performance is
to put the surface in a satisfactory condition for painting; therefore,
thorough cleaning is essential.
The cleaning procedure must include a complete
removal of rust and mill scale, solvent removal of any oil and grease, and
Painting at temperatures below 32 degrees F shall
not be done, except in urgent cases where authority has been obtained.
Under conditions of high humidity, the
temperature of the structure should be increased, or the air in
compartments cooled and dried to prevent condensation and to maintain a
Steel which is not to be galvanized.
Rust and mill scale shall be effectively removed
by acid-pickling, flame descaling or wire brushing as described in section
C-7 of the General Specifications, or by approved blasting process.
Grease shall be removed with noninflammible
solvent and surfaces wiped dry with rags. If specifically required
by the Supervisor of Shipbuilding, pitted surfaces otherwise acceptable
may be smoothed out with cement formula 62.
Whenever possible, cleaning of aluminum alloy
shall be done prior to assembly of parts. Cleaning before assembly
shall be accomplished by immersing the part in, or swabbing with, a
cleaner consisting of a dilute water solution of phosphoric acid and
organic solvents. The solution temperature shall be about 70 degrees
F. The solution shall remain in contact with the metal for not over
5 minutes. Residual solution shall be removed, with clear cold
water, followed by hot water, until no trace of acid is detected.
When necessary to clean after assembly, the
assembled parts shall be cleaned with mineral spirits, benzine, carbon
tetrachloride, trichlorethylene or a mixture thereof, in lieu of the
solution used for unassembled parts since acid may be retained between
faying surfaces and cause serious corrosion or breakdown of paint
Light sandblasting, following the use of above
solvents, is permissible for producing a good adhering surface for paint,
provided care is exercised to control the force and direction of the blast
as not to distort or damage the material.
Welded shall have all the traces of flux removed
before painting. This may be accomplished by brushing the welds
while immersed in boiling water. For inaccessible welds, the part
may be cleaned by immersing in a cold solution of10 percent sulphuric acid
for 30 minutes, or a 5 percent solution of sulphuric acid held at 150
degrees for 10 minutes. The acid should contact both the inside and
outside surfaces. The above cited treatments shall be followed by a
thorough rinse in clean warm water until no trace of the acid is
detected. Residual flux may be detected by leaching the surface with
distilled water, and adding a few drops of 5 percent silver nitrate
solution to the leach. A white precipitate indicates the presence of
Galvanized surfaces to be painted.
All zinc-coated surfaces which are to be painted
shall be treated with an approved cleaner consisting of phosphates,
phosphoric acid, and suitable solvents and wetting agents to enable the
surface to be coated with a thin phosphate coating. Where the
galvanized material has not been procured in the treated condition, the
solution shall be painted on the galvanized surface with a large brush and
allowed to act with cold water, then with hot water, and when dry, formula
84 primer shall be applied. Care should be taken to minimize
handling of the surface following the coating and prior to the application
of the primer.
Corrosion-resisting steel, nickel-copper alloy,
copper and brass that are to be painted shall be cleaned with
noninflammible solvent. Welds shall be brushed with
corrosion-resisting metal wire brushes.
Steel not to be galvanized.
Pickled or furnace material, after scale removal
and when clean and dry, shall be spray painted with one coat of
zinc-chromate primer, formula 84. Tinted formulas such as formula
84G and formula 84R may be used to distinguish between various types of
During construction, area which become bare or
where rust shows shall be touched up after wire brushing with one coat of
primer, formula 84.
Before launching, the exterior only shall receive
one complete second coat of primer, formula 84. Above the waterline
this second coat of primer shall be tined a dark color such as formula
84D, shall be used also below the waterline on submarines to insure the maintenance
of a dark surface should there be any topcoat peeling.
Decks and platforms to be covered with cement, or
composition deck coverings (mastic or the like) shall not be given a
priming coat of paint, unless the decks during the construction period are
to be left sufficiently long for corrosion to be of a serious nature, in
which case they shall be painted for protective purposes as directed by
the Supervisor of Shipbuilding. Before coating with cement or
composition, the paint shall be removed down to bare metal.
After completion of interior constructions, the
after pickling coating shall be touched up. All surfaces not already
painted shall receive one coat of zinc-chromate primer, formula 84.
Exterior galvanized structure and the interior of
the superstructure of submarines shall be primed and painted.
Interior galvanized structure and equipment except submarine
superstructure are normally unpainted, unless painting is considered
necessary by the Supervisor of Shipbuilding.
Galvanizing destroyed by welding or cutting,
galvanized wire mesh, or expanded metal shall be touched up with one coat
of primer, formula 84, and shall be finish-painted the color of
surrounding superstructure, except in gasoline or fresh water tanks, where
the welded area shall be recoated with zinc, metal sprayed.
All galvanized areas to be painted shall receive
one complete coat of zinc-chromate primer, formula 84.
Frames and stanchions of aluminum pipe berths
shall not be painted.
Crew's clothes lockers, bins, shelves, etc., when
constructed of aluminum shall be left unpainted.
All aluminum surfaces which are to be painted
shall be given a priming coat of zinc-chromate primer, formula 84.
This priming coat shall be applied as soon as possible after the metal has
been cleaned, rinsed, and dried. If necessary, the priming coat
shall be touched up before application of subsequent coats.
Where aluminum alloys surfaces are to be made
brightwork, the priming coat will not be required. Such bright
surfaces shall, however, be waxed.
Where aluminum materials are to be given
finishing coats, or where appearance is unimportant, the faying surfaces
shall be coated with zinc-chromate primer, formula 84. Where the
material is to be left bright, as for crew's lockers, the faying surfaces
shall be coated with varnish, phenolic type, formula 80. Each of the
faying surfaces shall be painted and allowed to dry before being brought
together, and just before being brought together each shall be given an
additional coat of the required paint or varnish.
For nonwatertight joints, aluminum shall be
protected from contact with dissimilar metals, including galvanized steel,
and from contact with wood or other absorbent materials which tend to
become water-soaked, by an approved, nonabsorbent gasket material or by
sealing compound in accordance with Navy Department Specification 52C12.
Canton flannel which has been soaked thoroughly for at least 12 hours in
zinc-chromate primer, formula 84, may be used for parts subsequently to be
painted. For parts to be left bright, the impregnating medium shall
be varnish, phenolic type, formula 80. Gaskets of this type shall be
installed while wet.
Where gaskets or sealing compounds are used
between faying surfaces the second coat (wet) of primer may be omitted.
Wood in contact with aluminum shall be painted
before assembly with one coat of varnish, phenolic type, formula 80.
Sealing compounds, in accordance with Navy
Department Specification 52C12, shall be used for such nonwatertight work
as joints of ventilation ducts.
Watertight joints between aluminum parts, or
between aluminum and galvanized steel, shall be made tight by caulking on
both sides and without the use of gaskets or packing, wherever
possible. Where such caulking is not possible, or where aluminum is
in contact with material other than aluminum or galvanized steel, canton
flannel impregnated and installed as described above, approved gasket
materials, or caulking compounds in accordance with Navy Department
Specification 52C12, shall be used.
Crevices, such as those occurring between
aluminum bulkhead plating and airport and window frames, shall be sealed
with sealing compounds in accordance with Navy Department Specification
Asbestos paper, or similar absorbent material,
shall not be used in contact with aluminum.
All threaded parts of aluminum alloys, whether
aluminum alloy to aluminum alloy or aluminum alloy to a dissimilar metal,
shall be coated before assembly with an antiseize mixture of 50
percent zinc dust and 50 percent petrolatum.
Aluminum gratings shall be primed before
Aluminum airplane tracks shall have all surfaces
except wearing surfaces treated and painted in accordance with the
requirements for painting other aluminum material.
Bolts which are to be used in clearance holes in
aluminum, with the exception of the threaded portion, shall be coated with
sealing compound in accordance with Navy Department Specification 52C12
before being inserted in the holes.
The fastenings of aluminum alloys shall be in accordance
with the General Specifications for Building Vessels of the United States
Navy, edition 1936, Section C-6, except that zinc-chromate primer, formula
84 shall be used in lieu of zinc-chromate iron-oxide primer.
Label plates, regardless of material, which are
installed on aluminum structure of fittings, shall be imbedded in a
plastic sealing compound in accordance with Navy Department Specification
Surfaces of aluminum material which are not
readily accessible for inspection and maintenance after assembly, such as
the unexposed surfaces of insulation sheathing, quick-operating door
guards, etc., shall be given two coats of zinc-chromate primer, formula
Corrosion-resisting steel and copper-nickel alloy
will normally be left bright, except when painting is considered necessary
for appearance. Inaccessible areas and metal to be painted shall
receive one coat of primer, formula 84.
Copper and brass gage cases, electrical fixtures,
hatch and door frames, covers, ladder side stringers, pipe outside
machinery spaces and other parts not requiring frequent handling shall
receive one coat of primer, formula 84, and shall be finish painted.
Metal plaques, trophies, data plates, and
nonferrous metal requiring frequent handling shall not be painted, but for
camouflage purposes visible brightwork topsides must be kept at an
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