Sealing Compound MIL-S-8802
This temperature-resistant, two-component,synthetic rubber compound is used for sealing and repairing fuel tanks and fuel cell cavities. This compound is designed for an operating environment that may vary between -65°F and +250°F. It is produced in the following classifications:
Class A —Sealing material suitable for brushapplication
Class B—Sealing material suitable forapplication by extrusion gun and spatula
Class C — Sealing material suitable for fayingsurface sealing
Dash numbers after the classification codeindicate the allowed application time in hours before the curing cycle will have progressed to the point where it is no longer feasible to apply that particular batch of sealant. Class A dash numbers are –1/2 and –2. Class B dash numbers are –1/2, –2, and –4. Class C dash numbers are –20 and –80 (8 hours of application time with the remaining time allowed for working the material).
Example: Class A-2 designates a brushablematerial having an application time of 2 hours. Class B-1/2 designates an extrusion gun material having an application time of 1/2 hour. Class C-20 designates a faying surface sealant with an application time of 8 hours and a working life of 20 hours.
Sealing Compound MIL-S-81733
This accelerated, room temperature, curingsynthetic rubber compound is used in sealing metal components on weapons and aircraft systems for protection against corrosion. This sealant contains magnesium chromate as a corrosion inhibitor. The classification of this sealant compound is of the following types:
Type I — For brush or dip application
Type II— For extrusion application, gun orspatula
Type III — For spray gun application
Dash numbers after the type code are used todesignate the maximum application time in hours.
Type I dash numbers are –1/2 and –2. Type II dashnumbers are –1/2, –2, and –4. The Type III dash number is –1.
Many of the sealants previously discussed maybeflammable or may produce toxic vapors. When you are using any material designated as flammable, all sources of ignition must be at least 50 feet away from the location of the work. Toxic vapors are produced by the evaporation of solvents or the chemical reaction taking place in the curing sealants. When you are using sealants in confined spaces, such as fuel cells, fuselage, or wing sections, adequate local exhaust ventilation must be used to reduce the vapors below the maximum allowable concentration. The vapors must be kept at that level until repairs have been completed. Do not eat or smoke when you are working with sealants.
RECOMMENDED READING LIST
NOTE: you need to be sure that you are studying the latest revision.
Aviation Maintenance Ratings Fundamentals, NAVEDTRA 12010, Naval Education and Training Program Management Support Activity, Pensacola, Florida, July 1990, Chapter 4.
General Advanced Composite Repair Manual,Tech Order 1-1-690, Secretary of the Air Force, Washington, D.C., 1 August 1990, Sections 1 through 6.
Fabrication, Maintenance and Repair of Transparent Plastics, Command Headquarters, Washington, D. C., July 1982.
General Use of Cements, Sealants, and Coatings, NAVAIR 01-lA-507, Naval Air Systems Command, Washington, D. C., February 1987.
Aircraft Weapons Systems Cleaning and Corrosion Control, Naval Air Systems Command, Washington, D.C., 1 January 1992, Chapters 5 through 7.
Structural Sandwich Composites,MIL-HDBK-23A, Department of Defense, Washington D. C., June 1974, Chapters 15 and 16.