![]() | COMMERCIAL ENGINE STANDARD PRACTICES MANUAL | Dated: 03/09/2020 |
SPM 70-43-07 CHEMICAL TOUCH-UP SURFACE REFINISHING PROCESS FOR ALUMINUM | ||
TASK 70-43-07-380-007 |
1 . | General. |
WARNING: |
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A. | Aluminum surfaces from which the original anodized protective finish has been removed must be touched up or refinished to restore the protective film. The following treatment is used for spot touch-up, and the solution may be brushed, or sponged on the prepared area. |
2 . | Materials. |
Subtask 70-43-07-380-071 |
CAUTION: |
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CAUTION: |
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A. | Interchangeability. You can use the materials specified by MIL-DTL-81706 Type-I (with Hexavalent Cr) and listed in QPL-81706 as alternatives to the materials in the table that follows if: |
- they are from the same class, and |
- they use the same method of application. |
The materials in QPL-81706 and the materials in the table that follows will give equivalent protection if they are from the same class and method of application. |
3 . | Procedure. |
Subtask 70-43-07-380-072 |
A. | Refinish exposed areas as directed in the following steps. |
(1) | Clean surface with liquid solvent degreaser such as C04-002 , C04-003 , C04-035 , or other approved non-hazardous solvent, using a clean brush or lint-free cloth. |
WARNING: |
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CAUTION: |
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(2) | Sand area lightly, using 180-grit, aluminum oxide abrasive paper. |
CAUTION: |
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(3) | Alternative procedure available. If using C03-081 or C03-082 , apply the refinishing solution as follows: |
(a) | Apply the refinishing solution with an acid-resistant nylon-bristle brush or cellulose sponge. Keep part wet with solution until coating is fully formed - usually from one to 10 minutes. |
(b) | Rinse off the refinishing solution thoroughly by flushing with clear water, by immersion in overflowing water (120 to 140°F (49 to 60°C)), or by removing excess solution with a wet sponge. Do not rinse with the jet from a hose or with a pressure-spray, and do not permit liquids to remain in cavities or depressions in the part. A blast of clean shop air may be used to blow liquids from the part. |
(3).A. | Alternative procedure. If using C03-084 , apply the refinishing solution as follows: |
(a) | Mix parts A and B together in equal volume, stirring thoroughly. |
(b) | Apply refinishing solution C03-084 with an acid-resistant nylon-bristle brush or cellulose sponge. Keep part wet with solution until coating is fully formed - usually from one to 10 minutes. |
(c) | Rinse off the refinishing solution thoroughly by flushing with clear water, by immersion in overflowing water (120 to 140°F (49 to 60°C)), or by removing excess solution with a wet sponge. Do not rinse with the jet from a hose or with a pressure-spray, and do not permit liquids to remain in cavities or depressions in the part. A blast of clean shop air may be used to blow liquids from the part. |
CAUTION: |
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(3).B. | Alternative Procedure. If you use C03-092 , apply the refinishing solution manually with the pen as follows: |
(a) | Apply an initial coating in one direction, with a 50 percent overlap on each pass. Allow this coat to dry and apply a second coat at right angles, again with a 50 percent overlap on each pass. Repeat this step for 5 minutes. |
(b) | After the conversion coating, do not rinse the parts. |
(c) | Dry the part with shop air. |
(3).C. | Alternative Procedure. If you use Bonderite M-CR 871 Aero C03-113, apply the refinishing solution manually with the pen as follows: |
(a) | Apply an initial coating in one direction, with a 50 percent overlap on each pass. Allow this coat to dry and apply a second coat at right angles, again with a 50 percent overlap on each pass. Repeat this step for 5 minutes. |
(b) | After the conversion coating, do not rinse the parts. |
(c) | Dry the part with shop air. |
(3).D. | Alternative Procedure. If you use Surtec 650 C03-113, apply the refinishing solution manually with the pen as follows: |
(a) | Apply an initial coating in one direction, with a 50 percent overlap on each pass. Allow this coat to dry and apply a second coat at right angles, again with a 50 percent overlap on each pass. Repeat this step for 5 minutes. |
(b) | After the conversion coating, rinse the parts. |
(c) | Dry the part with shop air. |
(3).E. | Alternative Procedure. If you use S1212, apply the refinishing solution as follows: |
(a) | Apply refinishing solution S1212 with an acid-resistant nylon-bristle brush or cellulose sponge. Keep part wet with the solution until coating is fully formed which is 5 minutes. |
(b) | After the conversion coating, rinse the parts. |
(c) | Dry the part with shop air. |
(4) | Check the color and texture of the coating. The coating is usually a golden iridescent color, although the color may vary with different alloys and processing conditions. If coating is powdery, the treatment time was longer than necessary. Powdery coating should be removed and coating redone. |
(a) | C03-081 , C03-082 , C03-084 , and C03-092 usually produces a golden iridescent color. |
(b) | C03-113 and S1212 produce iridescent, colorless to faintly blue and visible layer. |
CAUTION: |
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CAUTION: |
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(5) | If you paint the part, let the surface coating set for at least 30 minutes to cure before applying the paint. |
(6) | Store touch-up solution in a plastic container. It will deteriorate in plain glass or steel containers. |