Dow Corning 4 Electrical Insulating Compound - MIL-S-8660B
Grease like material containing an inert silica filler in combination with selected polydimethyl silicone fluids
Applications: A moisture proof seal for aircraft, automotive and marine ignition systems and spark plug connections, disconnection junctions in electrical wiring systems also in electrical assemblies and terminals.
How to Use: DOW CORNING 4 Compound can be applied by hand, specially designed automated equipment, brushing or wiping. Certain designs of grease guns may seize up with silicone compounds; test prior to use. A thinner consistency can be achieved by dispersing in solvents such as xylene, mineral spirits and methyl ethyl ketone. DOW CORNING 4 Compound can then be applied by brushing, dipping or spraying. DOW CORNING 4 Compound should not be applied to any surface which will be painted or finished. Such coatings may not adhere to the silicone-treated surface. If contaminated by a silicone coating, parts can be wiped or washed with solvent, washed with detergent, or immersed in an alcoholic potassium hydroxide solution and then rinsed in clear water before painting.
Dispensing: Separation and compaction can occur with some high pressure dispensing equipment. This should be considered when designing dispensing systems for use with DOW CORNING 4 Compound.
Solubility: DOW CORNING 4 Compound is insoluble in water, methanol, ethanol or mineral oil and is soluble in mineral spirit and methyl ethyl ketone. The suitability of a particular solvent should be based on testing prior to use. Flammability and toxicological properties should be important considerations in the choice of solvent.
Dimethyl silicone compounds should not be applied to O rings or other components made of silicone rubber because they will destroy the silicone rubber.
These compounds will also slightly swell natural butyl rubbers.
Chemical Resistance: DOW CORNING 4 Compound is not greatly affected by mineral oils, vegetable oils or air. It is generally resistant to dilute acids and alkalines, and to most aqueous solutions. As each application may vary in chemical composition, pressure, flow velocity, relubrication requirements and equipment design, it is recommended that DOW CORNING 4 Compound be tested before adopting for regular use.
DOW CORNING 4 Compound is not intended to be used with liquid oxygen and should not be used in applications requiring LOX compatibility without thorough testing for the specific application.