Preliminary Requirements

Safety Requirements

WARNING

IT IS THE RESPONSIBILITY OF THE OPERATOR TO OBTAIN AND OBSERVE THE MANUFACTURER'S MATERIAL SAFETY SHEETS FOR THE CONSUMABLE MATERIALS, AND ALSO TO TAKE LOCAL REGULATIONS INTO CONSIDERATION. THE SAFETY DATA SHEETS CONTAIN SAFETY INFORMATION SUCH AS HAZARDOUS INGREDIENTS, PHYSICAL/CHEMICAL CHARACTERISTICS, FIRE, EXPLOSION, REACTIVITY, AND HEALTH HAZARD DATA, PRECAUTIONS FOR SAFE HANDLING, AND USE AND CONTROL MEASURES.

Procedure

1. SUBTASK 70-38-42-380-001 Preparation of Aluminum Coating Compound

   1. Fully mix the CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER. Continue to mix the compound while you apply the compound to make sure that the solids do not come out of suspension.

      1. It is necessary to use CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER as-received. It is not permitted to add water, or other thinner, to the compound.

2. SUBTASK 70-38-42-380-002 Preparation of Surface

   1. If there is grease or oil on the part, do SPM TASK 70-11-03-300-503 to clean the part.

   2. Apply masking material to the part by SPM TASK 70-38-24-300-503 as necessary to keep the coating compound away from surfaces that are not specified to get coating. If the part has openings to internal spaces, seal the openings or put covers on the openings to keep the coating compound away from internal surfaces that are not specified to get coating.

      NOTE

      The abrasive blast machine that you use for this step must be dedicated to operations that prepare part surfaces for paint. It is not permitted to use this abrasive blast machine for other types of abrasive blast operations.

   3. Dry abrasive blast the part surface with CoMat 05-196 ALUMINUM OXIDE, 180-GRIT (180-grit), CoMat 05-197 ALUMINUM OXIDE, 240-GRIT (240-grit), or CoMat 05-022 ALUMINUM OXIDE ABRASIVE (240-grit) by the procedure in SPM TASK 70-12-09-120-501 (No. 240 or No. 320 Aluminum Oxide Grit) to get a clean, matte finish with no visible residue or stains.

      1. Make sure that the abrasive grit contains no organic material, such as grease or oil.

      2. Do not touch the part with bare hands during or after abrasive blast. Wear clean, discardable cotton or nitrile gloves when you touch the part.

         NOTE

         The compressed air line must have an oil separator and a water separator.

   4. Blow clean with clean, dry compressed air at 30 psi (206.8 kPa) maximum to remove all remaining media.

      1. Do not let grit or cleaning media collect in part crevices.

   5. It is necessary to apply the CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER to the part as soon as possible after you abrasive blast the part, but no more than four hours after the abrasive blast.

3. SUBTASK 70-38-42-380-003 Application of Coating

   1. 

      CAUTION

      SILICONE MATERIALS IN THE AREA WHERE YOU APPLY CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER CAN PREVENT A SATISFACTORY BOND BETWEEN THE PART AND THE COATING.

      Keep the area where you apply CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER fully isolated from all silicone materials (such as sealants, adhesives, greases, and spray lubricants). Silicone materials are not compatible with procedures to apply non-silicone coating materials.

   2. 

      CAUTION

      OILS IN THE AREA WHERE YOU APPLY CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER CAN PREVENT A SATISFACTORY BOND BETWEEN THE PART AND THE COATING.

      Keep the area where you apply CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER fully isolated from all penetrating oils and corrosion protection oils.

      NOTE

      The compressed air line must have an oil separator and a water separator.

   3. Use a spray gun to apply the CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER to get a coating layer with sufficient thickness that the coating thickness will be 0.001 in. - 0.003 in. (0.025 mm - 0.076 mm) after the Step burnish procedure. Make sure that there is a full layer of CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER on all surfaces where coating is specified.

      1. It is permitted to use a nozzle spray and then a roller to apply the CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER to the inner diameter (ID) surface of shafts.

      2. Do not burnish the applied CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER until the Step Cure procedure is completed.

4. SUBTASK 70-38-42-380-004 Cure

   1. Let the part dry at ambient temperature for 15 minutes minimum, or until the color of the applied CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER is an equal matte light gray.

      1. If the humidity is sufficiently high to cause the applied CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER to dry too slowly at ambient temperature, it is permitted to dry the part at approximately 100 deg F - 125 deg F (38 deg C - 52 deg C) in an oven that has air movement until the color of the applied CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER is an equal matte light gray.

   2. Dry the part in an air oven at 150 deg F - 200 deg F (66 deg C - 93 deg C) for 15 minutes minimum.

   3. Apply heat to increase the temperature of the part in an air oven at to 625 deg F - 675 deg F (329 deg C - 357 deg C) in an air oven, then keep the part in this temperature range for 30 minutes minimum.

5. SUBTASK 70-38-42-380-005 Burnish

   1. 
      CAUTION
      IF YOU BURNISH THE COATING TOO MUCH, THE THICKNESS OF THE COATING WILL DECREASE TOO MUCH, WHICH WILL DECREASE THE LIFE OF THE COATING.

      Burnish the coating.

      NOTE

      It is permitted to use manual procedures or automated procedures to burnish the coating, but automated procedures give more consistent (constant) results.

      1. Use one of the subsequent procedures to burnish the coating until the coating has a surface electrical resistance of 5 ohms maximum. Use an ohmmeter and two probes to measure the surface electrical resistance of the burnished coating. The distance between the points where the ohmmeter probes touch the coating must be 1 in. (25.4 mm) minimum, and the probes must not go fully through the coating to directly touch the base metal of the part.

         NOTE

         It is permitted to use manual procedures or automated procedures to burnish the coating, but automated procedures give more consistent (constant) results.

         1. Dry abrasive blast the coating with CoMat 05-022 ALUMINUM OXIDE ABRASIVE (240- grit), CoMat 05-197 ALUMINUM OXIDE, 240-GRIT (240-grit), or CoMat 05-198 ALUMINUM OXIDE, 320-GRIT (320-grit).

            1. Use 5 psi - 10 psi (34 kPa - 69 kPa) machine air pressure for pressure-type machines or 25 psi - 35 psi (172 kPa - 241 kPa) machine air pressure for suction-type machines.

            2. Nozzle sizes from 1/4 in. (6 mm - 6.5 mm) nominal orifice inner diameter (size No. 4) to 1/2 in. (12 mm - 12.7 mm) nominal orifice inner diameter (size No. 8) are permitted. Use a 3 in. - 4 in. (76 mm - 102 mm) nozzle-to-part distance at a 45 degree - 60 degree angle to the work surface.

         2. Lightly rub the coating with Grade 0000 steel wool.

         3. Lightly rub the coating with CoMat 05-125 ABRASIVE PAD, SILICON CARBIDE, ULTRA-FINE or CoMat 05-126 ABRASIVE PAD, ALUMINUM OXIDE, VERY FINE.

6. SUBTASK 70-38-42-380-006 Burnished Coating Thickness Inspection

   1. Do an inspection of the thickness of the burnished coating. The burnished coating thickness must be 0.001 in. - 0.003 in. (0.025 mm - 0.076 mm).

7. SUBTASK 70-38-42-300-001 Touch-Up Of Heat And Corrosion Resistant Aluminum Coating

   1. Procedure applicability.

      Condition	Touch-Up Procedure Applicability
      Scratches or scuff marks	Applicable
      Blended areas or machined areas	Applicable
      Chipped coat or flaked coat	Applicable
      Blistered paint	Not applicable. It is necessary to fully remove the paint and corrosion by SPM TASK 70-11-05-300-503, and to replace the paint.
      Pits that agree with Engine Manual or CIR Manual service limits, and show no corrosion.	Applicable for local areas.
      All other pitting	Not applicable. It is necessary to fully remove the paint and corrosion by SPM TASK 70-11-05-300-503, and to replace the paint.
      Superficial corrosion	Applicable

   2. Surface preparation.

      1. Sand the area to bare metal with 180 grit aluminum oxide abrasive cloth.

      2. Examine the area to be coated to be sure that no corrosion is remaining that there is no pitting, and that the part agrees with the specified Engine Manual inspection limits for part dimensions. If the area shows pitting, then it is not permitted to continue this touch-up procedure, and it is necessary to fully remove and replace the coat on the part.

      3. Clean the prepared area to be painted, use SPM TASK 70-11-26-300-503. Do not touch area with bare hands after cleaning.

   3. Apply the aluminum coating compound.

      1. Fully mix the contents of the CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER. Continue to mix the compound to make sure that the solids do not come out of suspension while you apply the compound.

         1. It is necessary to use the CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER as received. It is not permitted to add water, or other thinner, to the compound.

            NOTE

            The compressed air line must have an oil separator and a water separator.

      2. Use a brush or spray gun to apply the CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER to the repair surface to get a coat thickness of 0.0008 in. - 0.002 in. (0.021 mm - 0.050 mm) after burnishing. Make sure that there is a full layer of CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER on the repair surface.

   4. Cure the applied aluminum coating compound.

      1. Let the part dry at ambient temperature for 15 minutes minimum, or until the color of the applied CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER is an equal matte light gray.

         1. If the humidity is sufficiently high to cause the applied CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER to dry too slowly at ambient temperature, it is permitted to dry the part at approximately 100 - 125 deg F (38 - 52 deg C) in an oven that has air movement, or with local heat sources such as heat lamps or heat guns, until the color of the applied CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER is an equal matte light gray.

      2. Dry the part in an air oven at 150 - 200 deg F (66 - 93 deg C) for a minimum of 15 minutes. It is permitted to use local heat sources, such as heat lamps or heat guns, as an alternative to the air oven. The temperature of the part surface in the touch-up area must be in the specified temperature range for the specified time.

      3. Cure the coat in an air oven at 625 - 675 deg F (329 - 357 deg C) for 30 minutes minimum. If the part is an assembly, make sure that the selected cure temperature is not too high for each detail in the assembly. The temperature of the part surface in the touch-up area must be in the specified temperature range for the specified time.

         1. As an alternative to the oven cure, it is permitted to use local heat sources (such as heat guns that can supply hot air at 475 - 525 deg F (246 - 274 deg C), or heat lamps) to keep the repair surface at 400 deg F (204 deg C) minimum for 30 minutes minimum.

   5. Burnish the aluminum coating.

      NOTE

      If you burnish the coat too much, the thickness of the coat will decrease too much, which will decrease the life of the coat.

      NOTE

      When you measure the surface electrical resistance, the distance between the ohmmeter probes must be 1 in. (25.4 mm) minimum, and the probes must not fully go through the coat to touch the part material.

      NOTE

      If you do not burnish the applied CoMat 07-175 COATING COMPOUND - ALUMINUM, INORGANIC BINDER, it will be in its non-conductive state, and thus will give only simple barrier protection. The burnish operation is necessary to put the cured paint surface in its conductive state, which gives the paint its sacrificial protection properties.

      1. Burnish the coat to get a surface electrical resistance of 5 ohms maximum. Use one of the procedures in the subsequent list to burnish the coat.

         1. Rub the coat lightly with Grade 0000 steel wool.

         2. Rub the coat lightly with CoMat 05-126 ABRASIVE PAD, ALUMINUM OXIDE, VERY FINE or CoMat 05-125 ABRASIVE PAD, SILICON CARBIDE, ULTRA-FINE.

   6. Inspection of the coating thickness.

      1. Do an inspection of the coating thickness.

         1. The thickness of the coating after burnishing must be 0.0008 in. - 0.002 in. (0.021 mm - 0.050 mm).