Preliminary Requirements

Procedure

1. SUBTASK 72-38-11-110-053 Clean the Area for Repair

   1. 
      CAUTION
      SURFACES FOR REPAIR MUST BE FULLY CLEANED AND NOT TOUCHED BY HAND.

      Clean the area to be coated.

      1. Refer to the SPM TASK 70-11-26-300-503.

2. SUBTASK 72-38-11-220-086 Examine the Inlet Cone Assembly

   1. Refer to Figure.

   2. Visually examine the area for repair to make an estimate of quantity of damage.

   3. If the polyurethane coat is damaged, but the epoxy varnish coat stays fully.

      1. Do Step, Step and Step.

   4. If the polyurethane coat and epoxy varnish coat are damaged.

      1. Do Step, Step, Step and Step.

3. SUBTASK 72-38-11-350-056 Prepare the Inlet Cone Assembly for Surface Protection

   1. Refer to Figure.

   2. If the polyurethane coat is damaged.

   3. Carefully cut away any loose polyurethane coat.

      1. Use a scalpel.

      2. Be careful not to sever or damage the epoxy varnish coat and glass fibre below.

   4. If the polyurethane and epoxy varnish coat are damaged.

   5. Carefully cut away any loose polyurethane and/or epoxy varnish coat.

      1. Use a scalpel.

      2. Be careful not to sever or damage the glass fibre below.

   6. Rub down the damaged area for repair, feather the edges and make smooth.

      1. Use CoMat 05-021 WATERPROOF SILICON CARBIDE or CoMat 05-020 WATERPROOF SILICON CARBIDE.

4. SUBTASK 72-38-11-110-054 Clean the Area for Repair

   1. Clean the area to be coated.

      1. Refer to the SPM TASK 70-11-26-300-503.

5. SUBTASK 72-38-11-350-057 Apply the Epoxy Varnish Coat

   1. NOTE

      This procedure is only used when the epoxy varnish coat is damaged.

      Refer to Figure.

   2. Mask the areas not to be coated.

      1. Use CoMat 02-019 TAPE, ADHESIVE PAPER HEAT RESISTING MASKING.

   3. Mix equal volumes of the epoxy primer base and caterlyst.

      1. Use CoMat 07-080 TWO-PACK EPOXY PRIMER AND CATALYST and CoMat 07-081 EPOXY PRIMER CATALYST.

         1. If required, CoMat 07-082 THINNER may be added up to 10 percent of volume.

         2. The mixture must be allowed to stand for 30 minutes before use.

   4. Apply one coat of primer.

      1. Use a good quality brush or spray gun.

   5. Remove any unwanted primer from the repair area.

      1. Use a clean solvent moist lint free cloth.

   6. Apply one more coat of primer to a minimum thickness of 0.001in. (0.025 mm).

      1. Air dry for four hours at a minimum temperature of 60 deg F (16 deg C).

   7. Make up the epoxy finish.

      1. Use CoMat 07-079 BRIGHT ALUMINIUM and CoMat 07-007 TWO-PACK EPOXY FINISH (WHITE) AND CATALYST in equal volume or CoMat 07-117 EPOXY MATT FINISH-BLACK and CoMat 07-120 CATALYST (FOR MATT FINISH) for matt finish in equal volume or CoMat 07-119 EPOXY GLOSS FINISH-WHITE and CoMat 07-118 CATALYST (FOR GLOSS FINISH) for gloss finish in equal volume.

         1. The mixture must be allowed to stand for 30 minutes before use.

   8. Apply one coat of the epoxy varnish.

      1. Use a good quality brush or spray gun.

   9. Apply one more coat of the epoxy varnish to a minimum thickness of 0.001 in. (0.025 mm).

      1. Air dry for four hours at a minimum temperature of 60 deg F (16 deg C).

         1. The coat is hard-dry after six hours.

   10. If necessary, apply one more coat of the epoxy varnish.

   11. Remove the masking tape.

6. SUBTASK 72-38-11-350-058 Apply the Polyurethane Top Coat

   1. Refer to Figure.

   2. 
      CAUTION
      SURFACES FOR REPAIR MUST BE FULLY CLEANED AND NOT TOUCHED BY HAND.
      CLEAN COTTON OR POLYTHENE GLOVES MUST BE WORN.

      Make sure the surface for repair is fully clean.

      1. Use CoMat 06-021 SURFACE INSPECTION FLUID with a clean, soft-hair brush and quickly apply a constant thickness of fluid over the surface.

         1. If the surface of liquid breaks in less than 30 seconds, do Step again.

   3. Remove CoMat 06-021 SURFACE INSPECTION FLUID.

      1. Use CoMat 01-060 ACETONE (CH3)2CO and let the surface dry.

   4. Mask the area not to be coated.

      1. Use CoMat 02-019 TAPE, ADHESIVE PAPER HEAT RESISTING MASKING.

   5. Mix resin, hardener and methylethylketone.

      1. Use CoMat 08-069 RESIN, CoMat 08-068 HARDENER and CoMat 01-076 METHYL ETHYL KETONE.

         1. Resin parts by weight 100, hardener parts by weight 13.5 and methylethylketone parts by weight 40 to 70.

   6. Apply a constant coat of the polyurethane.

      1. Use a good quality brush or spray gun.

      2. Air dry for 30 minutes.

   7. NOTE

      One coat gives a thickness of approximately 0.003 in. (0.076 mm).

      Apply a constant coat of the polyurethane.

      1. Do Step again.

      2. Make sure the coat is applied level with the first coat and the aerodynamic surface is made smooth.

   8. NOTE

      A number of coats may be necessary because of surface sagging. It is permitted to gel immediately after you spray, by use of oven for 30 minutes at 248 to 266 deg F (120 to 130 deg C) to build up.

      Remove any unwanted polyurethane from the repair area.

      1. Refer to the SPM TASK 70-11-26-300-503.

   9. Cure the coat.

      1. Cure for two hours at 167 to 185 deg F (75 to 85 deg C) followed by four hours at 248 to 266 deg F (120 to 130 deg C) in applicable oven.

   10. Remove the masking tape.

7. SUBTASK 72-38-11-210-052 Examine the Repaired Area of the Inlet Cone Assembly

   1. Refer to Figure.

   2. Visually examine the repaired areas.

      1. Make sure the aerodynamic surface is smooth.

      2. It is accepted if the color is not equal.

Figure: Repair minor damage of the protection coating on the inlet cone assembly

Repair minor damage of the protection coating on the inlet cone assembly