Preliminary Requirements

Safety Requirements

WARNING

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

CAUTION

SURFACE TREATMENT (SUCH AS, ABRASIVE BLASTING), IF NOT DONE CORRECTLY, CAN CAUSE A SMEARED SURFACE OR UNWANTED EROSION (MATERIAL REMOVAL). THIS MAKES SURFACE DEFECTS NOT EASY TO FIND DURING NON-DESTRUCTIVE INSPECTIONS. DIFFERENT MATERIAL AND PROCESSES WILL SHOW DIFFERENT EFFECTS. THUS IT IS VERY IMPORTANT TO FOLLOW VERY CAREFULLY THE INSTRUCTIONS IN THE STANDARD PRACTICES/PROCESSES MANUAL AND ENGINE MANUAL. IF CAREFULLY DONE, THE APPROVED NON-DESTRUCTIVE INSPECTION (ESPECIALLY FPI) WILL CONTINUE TO HAVE RESULTS THAT ARE VERY ACCURATE.

CAUTION

IT IS NOT PERMITTED TO MIX THE VARIOUS BLASTING MEDIA.

CAUTION

THE USE OF ALTERNATIVE SIZE MEDIA OR MATERIAL TO THOSE SPECIFIED IN THE PROCEDURE IS NOT PERMITTED.

CAUTION

THE SPECIFIED ALUMINUM OXIDE IS FOR NEW MATERIAL ONLY. DO NOT USE RECYCLED OR RECOVERED MATERIAL.

CAUTION

YOU MUST NOT USE ABRASIVE BLASTING UNLESS DIRECTLY SPECIFIED IN THE ENGINE MANUAL. IF YOU DO NOT OBEY THIS INSTRUCTION THE PART(S) CAN BE DAMAGED.

CAUTION

DO NOT USE THIS PROCEDURE FOR CLEANING OR STRIPPING TITANIUM PARTS.

CAUTION

WHEN THIS PROCEDURE IS SPECIFIED FOR CLEANING PARTS BEFORE FPI OR FMPI, THE PART MUST FIRST BE CLEANED BY SPM TASK 70-11-54-300-503.

Procedure

1. SUBTASK 70-12-13-120-001 Make up and Control of the Slurry

   1. This slurry is required to be changed within 40 hours of use. For the make up of the slurry refer to SPM TASK 70-12-13-100-501 . . For the control of the slurry refer to SPM TASK 70-12-13-200-502.

2. SUBTASK 70-12-13-120-002 Machine Requirements

   1. The machine must be equipped with a timer to record hours of operation.

3. SUBTASK 70-12-13-120-003 The Procedure of Wet Abrasive Blasting (Suction Type Machine)

   1. Degrease the component, if necessary (refer to TASK 70-11-03-300-503).

   2. Mask the component, as necessary, to prevent abrasive entrapment.

      1. Install CoMat 02-348 AIRSEAL MASK on the knife-edge airseals to prevent erosion of the thermal spray coating. If the CoMat 02-348 AIRSEAL MASK is not sufficient to give the knife-edge airseal protection from the abrasive blast, install the CoMat 02-348 AIRSEAL MASK on the knifeedge airseal, and then apply a cover of masking tape from SPM TASK 70-34-18-380-501.

   3. Set machine air pressure to 40 psi to 50 psi (275.8 kPa to 344.7 kPa).

   4. 
      CAUTION
      DO NOT BLAST ON HARDFACE COATINGS UNLESS SPECIFIED BY STRIPPING INSTRUCTIONS IN THE ENGINE MANUAL OR THE STRIPPING PROCEDURE. HOWEVER, BLASTING OVERSPRAY IS PERMITTED.
      
      CAUTION
      IF THE BLAST STREAM DWELLS (STAYS) FOR TOO LONG ON AN AREA OF THE PART, THERE WILL BE UNWANTED EROSION (MATERIAL REMOVAL) IN THAT AREA, WHICH CAN CAUSE PART FAILURE OR DAMAGE THAT IS NOT POSSIBLE TO REPAIR.
      
      CAUTION
      THE USUAL RESULT OF THIS PROCESS WILL BE A DULL, MATTE GRAY FINISH. A SHINY, SILVER BLASTED SURFACE CAN BE THE RESULT OF TOO LONG A DWELL TIME (WHEN THE BLAST STREAM STAYS TOO LONG ON ONE AREA OF THE PART). THIS CAN PUSH PART MATERIAL ACROSS A CRACK AREA AND CAUSE UNWANTED EROSION (MATERIAL REMOVAL) IN THIS AREA. THIS CAN CAUSE PART FAILURE OR DAMAGE THAT IS NOT POSSIBLE TO REPAIR.
      
      CAUTION
      IF BLASTED PARTS HAVE A SHINY SILVER SURFACE, THE CAUSE CAN BE CHEMICAL CLEANING WHICH WAS NOT SUFFICIENT, INCORRECT CHEMICAL CLEANING PARAMETERS (TIME, TEMPERATURE, OR CONCENTRATION), OR OLD, BAD-CONDITION ABRASIVE BLAST SLURRY. TO GET THE BEST CLEANING PROCESS AND HELP PREVENT POSSIBLE DAMAGE TO PARTS, MAKE SURE THAT THE ABOVE CLEANING CONDITIONS ARE CORRECT.

      Blast the component with Solution Code 176 wet abrasive slurry, as necessary, to remove scale.

      1. There must be a 5 in. to 6 in. (127 mm to 152.4 mm) nozzle-to-part distance at a 45 deg to 60 deg angle to the work surface. Nozzle orifice inside diameter must be either 0.500 in or 12 mm.

      2. Do not let the blast dwell for more than two seconds (that is, do not point the blast stream at an area of the part for more than two continuous seconds). Use continuous movement of the nozzle to make sure that the blast stream hits equally all areas where it is necessary to blast.

4. SUBTASK 70-12-13-120-004 The Procedure After Wet Abrasive Blasting

   1. Remove masking.

   2. Pressure spray rinse the component in cold water or hot water.

      NOTE

      The necessary time in the hot water will increase as the number of parts in the tank increases, and as the size and mass of the parts increase.

   3. Put the part fully in hot water at 150 deg F to 200 deg F (66 deg C to 93 deg C) to increase the temperature of the part sufficiently to flash dry.

      NOTE

      If the water on the part does not flash off when the part comes out of the hot water, then the time interval that the part stayed in the hot water was too short.

   4. Remove the part from the hot water to flash dry. If the part has cavities and recesses, rotate the part as soon as possible to flash off the water.

   5. Blow dry the component with air at 30 psi (206.8 kPa) to remove any remaining water.

   6. Visually examine the part for even cleaning and that no blasting media, masking, or water is remaining.

   7. Preserve the parts in a corrosion preventive, as necessary. Refer to SPM TASK 70-38-05-380-501 or SPM TASK 70-38-37-300-503.