TO 35-1-3 - Robins Air Force Base

TO 35-1-3
or equivalent devices, to fog or spray the CPC MIL-PRF-
16173, Grade 4 or (MIL-PRF-81309 Type II), onto the interior
surfaces of the hollow members ensuring complete interior
coverage. Depot overhaul or contractor maintenance shall condition
the interior of aluminum hollow members per
TO 1-1-691 with a chromate conversion coating per MIL-
DTL-5541, Class 1A or anodize per MIL-A-8625, Type II or
III. The specific treatment shall depend on the alloy. Apply the
appropriate CPC, as above, after the pretreatment operations.
3.16 COATING APPLICATIONS.
3.16.1 Material Selection. To provide optimum protection
from deterioration and corrosion, the proper coating system (a
combination of cleaning, pretreatment, priming and topcoat)
must be selected for a specific application. See Table 3-1 for
authorized coating systems. Table 3-2 is a brief abstract of the
priming and painting functions necessary to maintain the coating
systems on SE.
Table 3-2. Pretreatment Instructions
Material
A. FERROUS ALLOYS other than
stainless steel, mill-galvanized or
mill-electrozinc coating, or mill-aluminized
surfaces.
Finish Process
1. Chemically clean the areas in accordance with Chapter 3. Remove all remaining
coating and corrosion by abrasive blasting or other mechanical cleaning processes.
Field organizations without abrasive blasting capabilities may proceed to
Step 3. Depot and/or contractor level of maintenance apply zinc phosphate
TT-C-490, Type I.
2. The blasted surfaces will be in a near-white condition per Steel Structures Painting
Council (SSPC-SP 10). A near-white blast cleaned surface finish is defined
as one from which all oil, grease, dirt, mill scale, rust, corrosion products, oxides,
paint or other foreign matter have been completely removed from the surface
except for very light shadows, very slight streaks, or slight discolorations caused
by rust stain, mill scale oxides, or slight, tight residues of paint or coating that
may remain. At least 95% of each square inch of surface area shall be free of all
visible residues, and the remainder shall be limited to the light discoloration
mentioned above. The National Association of Corrosion Engineers (NACE)
Standard TM-01-70 (Visual Standard for Surfaces of New Steel Airblast Cleaned
with Sand Abrasive) surface was produced as a visual standard to compare properly
prepared surfaces. The Standard may be procured from NACE International,
440 South Creek Drive, Houston, TX 77084-4906. The blast-cleaned surface
must be primed before any rusting occurs, otherwise the benefit of the near-white
blast cleaning is lost. Under normal atmospheric conditions it is best practice to
prime within one hour of blast cleaning.
The following areas are exceptions to blasting:
a. Abrasive blasting will not be performed on surfaces where there is a danger of
warping or distorting the base metal. Sheet metal thinner than 0.0625 inch (U.S.
Standard 16 gauge) will not be abrasive blasted.
b. Parts whose dimensions must be retained or parts with deep crevices, threads, or
machined surfaces will not be abrasive blasted.
c. Heavy cast iron or tempered steel components such as engines, transmissions,
gearboxes, differentials, leaf or coil springs, etc., shall not be abrasively blasted.
d. Working surfaces that are to be lubricated.
3-10