MIL-S-83318 Sealing Compound, Low Temperature Curing, Quick Repair Integral Fuel Tanks And Fuel Cell Cavities S/S By Sae-Ams-S-83318This specification covers a two component, temperature??resistant ??65??F to +250??F ??54??C to +120??C, low temperature 20??F minimum curing synthetic rubber compounds for quick repair of aircraft integral fuel tanks and fuel cell cavities. During application, the sealing compounds shall be a suitable, fluid consistency.

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MIL-S-83318A(USAF)

4.9.8 Fluid immersed curing time. An aluminum test panel conforming to temper T6 of QQ-A-250/13 and measuring 0.040 by 2.75 by 6 inch (1.00 by 70 by 150 mm) shall be cleaned in accordance with 4.7.1 and covered with sealing compound to a depth of

0.25-inch (6.3 mm) in one application. After curing at standard conditions for 2 hours, the test panel shall be immersed in jet reference fluid at 77°F (25°C). The hardness shall be determined after a total of 6 hours (4 hours in fluid) and after a total of 24 hours (22 hours in fluid) in accordance with method 3021 of FED-STD-601.

4.9.9 Peel strength. The type and quantity of panels listed in table lll shall be used for evaluation of peel strength. All panels shall be as described in figure 2. The thickness of the panels shall be as listed in table lll. The panels shall be prepared in accordance with

4.7.1. The adhesion promoter shall be applied as specified in 4.7.4. Sealing compound shall cover 5 inch (125 mm) of one side of the panel surface to a depth of 0.125 inch +0.016 (3.0

+ 0.5 mm). A 2.75 x 12 inch (70 x 300 mm) strip of cotton duck, conforming to CCC-C-419, type lll, or a strip of wire screen ( 20- to 40- mesh aluminum or model wire fabric) shall be impregnated with the sealing compound, so that approximately 5 inch (125 mm) at one end is completely covered on both sides. The sealant coated end of the fabric shall be placed on the sealant coated panel, and smoothed down on the layer of the sealing compound, taking care not to trap air beneath the fabric. An additional coating of sealing compound shall be applied over the fabric approximately 0.031 in (0.8 mm) thick. The sealant shall be given a standard cure as specified in 4.7.6. At the end of the sealing compound cure, two panels of each substrate listed in table lll shall be completely immersed in covered glass vessel in the following fluids and under the following conditions. (lmmersion in wide-mouth quart jars with 2 panels in each jar is suitable.)

1. 7 days at 140°F (60°C) in jet reference fluid

2. 7 days at 140°F (60°C) in equal parts jet reference fluid and 3% aqueous sodium chloride solution

ln addition, the panels coated with MlL-C-27725 shall be subjected to each the following test conditions:

1. 70 days at 140°F (60°C) in jet reference fluid with fluid change every 14 days

2. 70 days at 140°F (60°C) in equal parts jet reference fluid and 3% aqueous sodium chloride solution with fluid change every 14 days