Preliminary Requirements

Safety Requirements

WARNING

IT IS THE RESPONSIBILITY OF THE OPERATOR TO OBTAIN AND OBSERVE THE MANUFACTURER'S 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. 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

THE BLASTING CABINET AND MEDIA USED IN THIS PROCEDURE ON ENGINE PARTS MUST NOT BE USED TO STRIP CADMIUM PLATED PARTS OR CADMIUM PLATED/PAINTED PARTS, SUCH AS LANDING GEAR.

CAUTION

IT IS NOT PERMITTED TO MIX THE VARIOUS BLASTING MEDIA UNLESS PERMITTED BY A PROCEDURE.

CAUTION

THE DRY PROCEDURE MUST BE DONE IN A REDUCED PRESSURE CABINET TO CONTAIN THE BLASTING MEDIUM IN THE CABINET.

Procedure

1. SUBTASK 70-12-03-860-001 Equipment and Materials

   1. Consumable materials.

      CoMat 01-110 SODIUM BENZOATE C6H5COONa	Sodium benzoate (C6H5COONa)
      CoMat 01-111 SODIUM NITRITE NaNO2	Sodium nitrite (NaNO2)
      CoMat 01-293 GLASS BEADS	Glass beads size No. 5
      CoMat 05-007 GLASS BEADS	Glass beads size No. 11
      CoMat 05-009 GLASS BEADS	Glass beads size No. 13
      CoMat 05-162 GLASS BEADS	Glass beads size No. 6
      CoMat 05-166 GLASS BEAD	Glass shot AGB 6
      CoMat 05-170 GLASS BEADS	Glass beads size No. 12
      NOTE To identify the consumable materials refer to the PCI.

2. SUBTASK 70-12-03-120-001 Make-up and Control of Glass Bead Wet Blasting

   1. The mixture must be one part of glass beads to four parts of water by volume. For list of applicable glass beads, refer to Step.

   2. Make an inspection of the glass bead mixture to make sure the particles are not broken. Replace as necessary.

   3. When the mixture is to be replaced, the cabinet internals must be cleaned fully with clean water.

3. SUBTASK 70-12-03-120-004 Make-up and Control of Dry Glass Beads

   1. In the dry blasting process, the glass beads are used "as received". Follow the machine and bead manufacturers' instructions and do a check at regular intervals for distorted or broken beads and fines and replace as necessary. For a list of applicable glass beads, refer to Step.

4. SUBTASK 70-12-03-120-002 The Procedure to Use Glass Bead Blasting

   
   CAUTION
   ALWAYS APPLY MASKING TAPE OR INSTALL THE SPECIAL GUARDS TO THE COMPONENT SURFACES WHICH ARE NOT TO BE BLASTED. DO THIS BEFORE YOU BLAST THE COMPONENT. MAKE SURE NO BLASTING MEDIA GOES INTO THE COMPONENT AND BECOMES CAUGHT.

   1. Clean the components to remove the grease and the dirt as given in the Engine Manual.

   2. Seal all the areas that are not to be blasted.

   3. Set the blast air pressure.

      1. For a pressure-type machine, use a pressure of 20 to 40 psi (140 to 275 kPa) and, for a suction-type machine, use a pressure of 40 to 80 psi (275 to 550 kPa).

   4. Put the components on to the platform in the blasting cabinet or hold in a gloved hand.

      NOTE

      Although blasting time must be to a minimum necessary to clean the component, the Engine Manual can possibly give a longer time.

   5. Point the blast systematically on to the surface to be blasted for a minimum time necessary to clean the components.

5. SUBTASK 70-12-03-120-003 The Procedure After Glass Bead Blasting

   1. Clean the components fully in a flow of clean cold water immediately after blasting.

      NOTE

      A recommended inhibitor for the cold and hot water is a 2 to 1 mixture of CoMat 01-110 SODIUM BENZOATE C6H5COONa and CoMat 01-111 SODIUM NITRITE NaNO2. This mixture is added at a concentration of 12.5 g/l.

   2. Remove all the seals from the areas that was not blasted. Clean the components again in inhibited cold water and inhibited hot water at a minimum temperature of 176 deg F (80 deg C), then dry with dry air at pressure.

   3. Visually examine the parts to make sure all the blasting material remaining is removed. Repeat as necessary to remove all remaining unwanted material.

      NOTE

      When it is not necessary to do more procedures or protective treatment on a steel component, it must have temporary protection. Refer to the SPM TASK 70-38-05-380-501.

   4. Alternatively, the components can be cleaned with an air gun then put fully in to an approved dewatering oil. Refer to the SPM TASK 70-38-05-380-501.