APM HEXSEAL was founded in 1947 with the mission to develop and manufacture environmental sealing solutions to protect and prolong the life of electromechanical switches and circuit breakers in hostile environmental conditions worldwide. Initially for the military and subsequently for the industrial and commercial marketplace. This focused effort resulted in the development of an extensive line of standard silicone sealing boots that mate with the vast majority of switches, breakers, encoders, potentiometers & many other rotating devices found today throughout the world.

Other complimentary sealing products were also developed and patented including a complete line of reusable self-sealing and optional locking fasteners (featuring a captive 0-ring), and silicone colorizing incandescent lamp filters that transmit colors for instrument panels and lighted push-button switches.



Prevent switch failure with the APM Hexseal IQ toggle switch boot seal. Quickly and easily mounts over the toggle bat in just a few turns. IP68 protection.

APM Self Sealing Fastener and Washer Tutorial

Custom Capabilities

APM Hexseal develops reliable, cost-effective seals to meet your unique application needs. Here are some examples.

Remote Automotive Keyless Entry Control

Sealing Problem: • Seal the perimeter between mating top and bottom component covers. • Seal and color-code three printed circuit board-mounted pushbutton switches. • Provide a transparent viewing window for monitoring the PCB-mounted, battery-status LED. • Render the entire unit submersible.

APM Design Solution: A single-piece tri-color (black, green and clear) silicone rubber seal, geometrically-contoured to the control’s housing and internal electronic components. The seal, housing and circuit board are held together by one of APM HEXSEAL’s patented, reusable self-sealing fasteners.

Outdoor Audio System Keypad

Sealing Problem: • Seal and protect keypad from all kinds of weather conditions, dust, dirt, moisture. • Must tolerate sunlight and exposure to ozone. • Should be a single piece design. • Provide transparent viewing window that permits easy keypad operation.

APM Design Solution: A single-piece seal, precision molded with crystal-clear silicone rubber that nests neatly in a perimeter groove on the keypad’s front plate assembly.

Security System Access Keypad

Sealing Problem: • Geometric compatibility with pushbutton switch array. • Protect keypad from weather, water, dust, dirt and cleaning solvents. • Tolerate sunlight and exposure to ozone. • Provide durable switch identification designations. • Provide excellent tactile feedback of switch actuation.

APM Design Solution: A fitted, single-piece, custom-colored seal molded from a specially-formulated rubber with durable, recessed, high-contrast switch legend markings.

Programmable Digital Panel Meter

Sealing Problem: • Protect DPM’s front programming switches from water, oils, grease, dirt and cleaning solvents. • Permit easy reading of DPM’s switch markings. • Resist discoloring in presence of sunlight. • Not compromise programming ease. • Single-piece design.

APM Design Solution: A full-bezel soft seal fabricated from a special transparent rubber formulation. Form-fit design seals panel cut-out in which DPM is mounted, while permitting operation of the unit’s programming switches through the soft, flexible seal.

Lighted Pushbuttons for Military Aircraft

Sealing Problem: • Prevent penetration of moisture from fog or salt spray. • Tolerate kerosene, alcohol and light detergents. • Ensure pushbutton actuator remains attached to switch body under high-impact shock of up to 1,500 Gs. • Permit actuation of pushbutton. • Permit viewing of lighted indicator and switch legend.

APM Design Solution: A snap-on, single-piece bezel seal consisting of a custom stainless steel frame over which is molded a durable, chemically-resistant elastomer.

Missile Launch Control Circuit Breaker

Sealing Problem: • Protect circuit breaker from weather, salt spray, dust and dirt. • Permit easy resetting of tripped circuit breaker. • Permit viewing of circuit breaker status. • Resist yellowing or other discoloration due to aging or exposure to sunlight. • Meet stringent test requirements of MIL-B-5423.

APM Design Solution: A custom-molded boot made of APM’s proprietary, transparent elastomer (RubRGlas™) and a painted steel frame featuring filled engraved legends. The boot and frame are secured to the circuit breaker using APM’s patented reusable self-sealing fasteners (SEELSKREWS™).

Food Processing Equipment

Sealing Problem: • Meet cleanliness and corrosion-resistant requirements of the food and beverage processing industry. • Protect pushbutton actuator from frequent washdowns. • Provide mechanical advantage to actuate the pushbutton control. • Seal the panel cutout in which the pushbutton is mounted.

APM Design Solution: A unitary pushbutton switch seal assembly consisting of a durable, fluorosilicone rubber boot encased in a stainless-steel actuator housing.

Other industry applications: Equipment for meat packing, dairy processing, fast-food and commercial cooking equipment, pharmaceutical, medical/dental, hydraulic lift mechanisms on trash and other hauling vehicles’ controls, remote crane & locomotive controls, sewage equipment, underwater/marine, agricultural, car wash, and military equipment controls

Download Literature

Environmental sealing boots for switches, potentiometers, and encoders.
24 pages [2.1mB]

Environmental sealing boots for circuit breakes, single and multi-pole.
16 pages [1.4mB]

Self-sealing fasteners. Threadlockers and self-sealing washers, MIL MS3212, 3213, high pressure, reusable, vibration-resistant.
12 pages [2.5mB]

Colored silicone filters for miniature incandescent lamps.
4 pages [620kB]

Custom elastomeric seals
12 pages [2.5mB]

CFCI circuit breaker sealing boots.
1 page [238kB]

Inverted bellows toggle switch boots.
1 page [375kB]

Self-sealing washers, UL recognized, vibration-resistant, for electrical and mechanical environantal applications.
1 page [230kB]

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