b. Where an individual patch has been applied with unsuccessful results. Either type patch may be used as a
Where the ruptured area cannot be isolated, the paste mixture prior to curing acts as a temporary seal, after
which the liquid impregnated cloth is applied as a permanent repair. This is based on the premise that the paste mixture
will not wash away as readily as the liquid.
In a compound rupture, paste may be used as a filler to form a flat surface so the woven roving can be applied to
form a flat patch.
8-25. SUGGESTIONS FOR USING PLASTIC REPAIRS. Both the paste and liquid resins with their associated
hardeners always are mixed in the same proportions: four parts of resin to one part of hardener. The resin and hardener
are packaged in their proper ratio. Add the hardener to resin and mix thoroughly until a uniform gray color is observed.
It is advisable when mixing paste resin and hardener to remove the substances from the can and mix them on a dry,
clean board; in this way, uniform color of mix can be more easily observed.
One large can of liquid resin, 400 grams, when mixed with 100 grams of liquid hardener will give a total of 500
grams of activated resin, which is sufficient to thoroughly impregnate one strip of 6-inch by 40-inch woven roving. Two
grams of resin hardener mixture will impregnate 1 square inch of woven roving cloth. Determine the quantity of resin
hardener mixture required to impregnate the amount of woven roving to be used.
Do not mix resin and hardener until all other preparations have been completed.
Wear gloves provided to protect hands and face shields to protect the eyes when making any
repairs involving the use of plastic resins. In the event resins do come into contact with any part
of the body, wash with hot water and soap. Personal injury could result.
The patch should not be subjected to any pressure until the temperature of the patch has dropped below 1500 F.
8-26. PATCHING SAFETY PRECAUTIONS. Provide forced air supply and exhaust ventilation during the time plastic
materials are being used.
This is most important during the time that heat and the resultant fumes are given off. Also follow these precautions:
a. Prior to using plastic, use protective rubber gloves.
b. Only crew members in good health and free of any respiratory conditions or skin lesions should be exposed to