AN 01-25CN-2             PARAGRAPH 6
  (a) REPAIR MATERIALS.

   Cement-Inside or Outside-B & B Chemical Co. No. 868 solvent Methyl ethyl ketone liner repair material of any of the following:
B. F. Goodrich nylon sandwich No. 139BT3102. Goodyear Tire & Rubber Co. cell repair gum B.
Firestone Tire & Rubber Co. nylon fuel cell repair material No. 95102
United States Rubber Co. Buna repair material No. 1.
Hewitt Rubber Corp., nylon sandwich fuel cell repair material No. 85612.


  Outside Repair Material:

  Hewitt Rubber Corp. Buna coated fabric No. 612, .040 inch to .050 inch or equal.
TOOLS:
A pair of shears
Two 1-inch paint brushes
One 1/4-inch hand roller
One narrow edge gooseneck steel stitcher
Emery cloth, No. 40 to 80


  NOTES ON MATERIALS USED:

  Outside repair material is a fabric coated with synthetic rubber.

  The inside repair material consists of two layers of synthetic rubber, one of which is vulcanized and the other layer is unvulcanized and is *in contact with the Holland cloth. Before removing Holland cloth, buff the exposed side of the repair materials. The unvulcanized face, which is in contact with the Holland cloth, can be identified by the slightly tacky feel.

  Methyl ethyl ketone solvent can be used for washing the injury, removing sloshing compound, and livening up the cement. Petroleum naphtha, if available, can be used for washing the injury. This naphtha, if used, should be clean and free from grease or foreign material. It cannot be used to liven up the cement. Ethyl acetate, if available, can be used for removing sloshing compound.

  To prepare cement for use, mix thoroughly 5 teaspoons (12.5 cc) of accelerator into 1 pint of cement. Stir continuously while adding the accelerator. Cement 		      can normally be used for 6 to 8 hours after mixing, but should not be used after it shows a tendency to become jelly-like or soapy. Accelerator is used to harden or set the cement. Cement, when used, should be applied evenly and thinly. Two coats should be applied on each of the surfaces to be joined together, allowing cement to dry between coats.

CAUTIONS: Solvents and cement vapors are somewhat toxic if inhaled over a period of time. A respirator designed for organic vapors should be worn if operator is exposed to high vapor concentrations, such as working inside of cells for more than 1 hour in 24 hours. All vapors of cements and solvents are highly inflammable and should not be allowed to accumulate. No sparks, smoking, or open flames should be allowed near places where cementing, repairing, or mixing is being done.


  (b) PREPARATION.-Always remove all gasoline from the cell, as soon after injury as possible, and allow the cell to dry thoroughly. Drying may be hastened by circulating warm air through the cell and by keeping the cell in a warm place. The cell should not be kept warm for long periods and should not be heated to a temperature above 490C. (1200F.). Repairs may be started as soon as the sealing gum has resumed its normal appearance and is no longer swollen.

  (c) OUTSIDE REPAIRS.

    1. Cut a smooth round patch of fabric large enough to extend at least 21/2 inches in all directions from the edges of the injury.

    2. Buff one side of the patch and the outside of the cell for 3 inches in all directions from the edge of the injury with emery cloth. Buff until a considerable number of the cords show through.

    3. Support the cell around the injury so that the edges of the injury will be in proper alignment. Wet a clean rag with solvent and wash the buffed surfaces of the tank and patch. Apply two coats of cement to tank and to patch. Let dry between each coat.

    When the last coat is dry but still tacky, center the patch over the injury and roll down.

    To determine if the cement is property "dry" use the following test. As soon as a clean