Preliminary Requirements

Safety Requirements

WARNING

IT IS THE RESPONSIBLITY 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.

WARNING

CHROMIC ACID SPRAY IS INJURIOUS IF INHALED, CAUSING ULCERS IN THE NOSE AND IN SOME CASES, PERFORATION OF THE NASAL SEPTUM. CHROMIC ACID SALTS AND SOLUTIONS IN CONTACT WITH THE SKIN MAY CAUSE CHROME SORES. ULCERS MAY BE FORMED IF CHROMIC ACID GETS IN TO CUTS AND ABRASIONS.

WARNING

CHROMIC ACID SOLUTION MUST NEVER BE USED UNLESS THE FUME EXTRACTION PLANT IS IN OPERATION AND IS FULLY SERVICEABLE.

WARNING

BARRIER CREAM SHOULD BE APPLIED TO THE HANDS AND FOREARMS BEFORE STARTING WORK.

WARNING

PROTECTIVE CLOTHING MUST BE WORN, I.E. PROTECTIVE GLOVES, OVERALLS, GOGGLES OR FACE VISOR AND SAFETY SHOES OR BOOTS.

WARNING

SMOKING AND THE CONSUMPTION OF FOOD NEAR THE CHROMIC ACID BATH ARE PROHIBITED.

WARNING

CUTS AND ABRASIONS, WHICH APPEAR NOT TO BE HEALING READILY SHOULD BE REPORTED, WITHOUT DELAY, TO THE MEDICAL DEPARTMENT.

WARNING

CHROMIC ACID IS STRONGLY OXIDIZING AND ENTAILS SOME FIRE RISK I.E. POSSIBLE SPONTANEOUS COMBUSTION OF ORGANIC MATERIALS, SUCH AS RAGS AND SAWDUST, WHICH HAVE ABSORBED CHROMIC ACID SOLUTION. SUCH CONTAMINATED MATERIALS SHOULD BE IMMERSED IN A SOLUTION OF SODIUM BISULPHATE TO NEUTRALISE THE CHROMIC ACID, THE SOLUTION SHOULD THEN BE DISPOSED OF AS SPECIAL WASTE. THE SOLID MATERIAL SHOULD THEN BE RINSED WITH WATER PRIOR TO DISPOSAL.

WARNING

OPERATORS MUST WEAR THE PROTECTIVE CLOTHING PROVIDED, INCLUDING RUBBER GLOVES AND EYE PROTECTION.

TREAT EYE SPLASHES IMMEDIATLEY BY PROLONGED WATER IRRIGATION OF THE EYES, AND THEN GET IMMEDIATE MEDICAL TREATMENT.

Procedure

1. SUBTASK 70-33-58-330-001 Make-up and Control of Chromic - Phosphoric Acid Solutions

   1. 
      CAUTION
      MAKE SURE ONLY DEMINERALIZED WATER IS USED TO MAKE UP THE SOLUTION.

      Make-up.

      1. The solution is made up at a concentration of 1.2 oz (34 g) of CoMat 01-023 CHROMIUM TRIOXIDE CrO3(CHROM.ACID) in approximately 7.5 pt (3.4 l) of CoMat 01-201 DISTILLED, DEIONIZED, DEMINERALIZED, OR REVERSE OSMOSIS (RO) WATER. Then add 22.75 ml of CoMat 01-016 PHOSPHORIC ACID H3PO4. Adjust the volume to 1.2 gal (4.54 l) with CoMat 01-201 DISTILLED, DEIONIZED, DEMINERALIZED, OR REVERSE OSMOSIS (RO) WATER.

      2. The solution must be made up in a stainless steel tank that has fume extraction equipment installed.

   2. Control.

      1. Do an analysis of the chromic and phosphoric acid each week to make sure it is in the limits that follow:

         1. Chromic acid 7.5 to 10 g/l.

         2. Phosphoric acid 8 to 12 g/l.

      2. NOTE

         These frequencies can be increased if necessary.

         Do an analysis of the chlorides each month to make sure they are in the limits that follow:

         1. Chlorides 0.2 g/l maximum.

      3. The solution is satisfactory if it is red in color. Change the solution if the color changes.

2. SUBTASK 70-33-58-330-002 The Procedure to Remove the Chromate or Anodized Layer

   1. NOTE

      Step and Step are not necessary if the parts are cleaned and prepared during processing.

      Clean the parts. Refer to the SPM TASK 70-11-14-300-503.

   2. Vapor degrease the parts. Refer to the SPM TASK 70-11-01-300-503.

   3. 

      CAUTION

      THE PARTS MUST ONLY STAY IN THE SOLUTION FOR THE TIMES SPECIFIED IN THE ENGINE MANUAL. THIS IS TO PREVENT INTERGRANULAR ATTACK OR A DECREASE IN FATIGUE STRENGTH.

      NOTE

      When large parts are soaked it could be necessary to pre-heat them in boiling water. This will prevent a large decrease in the temperature of the solution.

      Let the parts soak in the solution for 10 to 20 minutes (unless specified differently in the Engine Manual). The solution must be kept at a temperature of 194 to 212 deg F (90 to 100 deg C).

   4. Remove the parts from the solution and clean them immediately in a flow of clean, cold water.

   5. Soak the parts in clean boiling water and then let them become dry.