APM Self-Sealing Fasteners
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APM Hexseal, originator and world's largest supplier of self-sealing fasteners
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Sealing Performance Under High Pressure

APM invented and patented the first pre-assembled self-sealing fasteners designed to provide both fastening and sealing integrity in a single unit. The APM design features an embedded resilient O-ring held captive in a precision engineered groove under the fastener head. Minimum O-ring friction and wear results in maximum reusability.

This combination of precise groove geometry and O-ring sealing characteristics results in a positive seal regardless of surface finish, by providing full 360° metal-to-metal surface contact. Re-usable and Vibration-resistant, SEELSKREWS®, SEELRIVETS®, SEELBOLTS®, and SEELNUTS® can withstand internal/external pressures up to 20,000 psig (137,895kPa)/vacuum at temperatures from –150°F to +500°F (-106°C to +260°C).

The APM one-step process eliminates the need for sealants and adhesives, thus eliminating concerns about hazard disposal or employee safety. Available with adjustable threadlocking and tamper-resistant head versions.

For applications requiring a high-pressure sealing washer, APM offers the SEELOC© air and water-tight self-sealing washer. Silicone is bonded to one side of a dish shaped stainless steel washer to achieve 100 psi internal/external sealing. Reusable and vibration-resistant, SEELOC© is used in conjuntion with standard screws and bolts, and features an IP66/68 ingress rating.



Embedded O-Ring Self-Sealing Fastener System vs. O-Ring and Washer Sealing View Comparison Chart

Embedded O-Ring Self-Sealing Fastener System vs. Liquid Sealing & Threadlocking Techniques View Comparison Chart

Since 1947, APM has received more than 100 patents for sealing and related technologies.

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mechanical and liquid-applied threadlocking add-ons for their comprehensive line of re-usable high-pressure self-sealing screws, bolts and nuts


Visit our Electronics Division for Switch, Circuit Breaker, Potentiometer Sealing Boots & Dynamic Custom Elastomeric Sealing Solutions.

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Switch & Potentiometer Boots
Circuit Breaker Boots
Custom Elastomeric Molding
Colorizing Lamp Filters


The World's Most Hostile Environments Are Our Proving Grounds®
For Electronics Controls As Well As Self-Sealing Fasteners

Since 1947,  the Electronics Division of APM HEXSEAL has lead the industry in developing and manufacturing  environmental protection sealing components for controls  that are mounted on switches, potentiometers and circuit breakers.  Using advanced elastomer molding technology, a broad range of sealing boots are produced to match most controls manufactures’ standard part numbers,  which are stocked by leading electronics and industrial distributors in the United States, Canada and World-wide. Most are IP66/68 ingress protection rated and UL recognized (third-party tested).  APM sealing products are used extensively in marine, medical, military, process industry, electronic instrumentation, off-road and construction equipment -- wherever hostile environmental/operational conditions exist.

HEXSEAL®, SEELSKREW®. SEELBOLT®, SEELNUT®, SEELRIVET®, SEELOC® are registered trademarks of APM Corp.

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