About us

Hermetic Seal Technology, Inc. (HST) is a leading manufacturer of high-performance custom glass-to-metal seals, lithium battery seals, and hermetic feedthroughs, serving critical industries such as medical, aerospace, defense, industrial, and energy. Founded in 1994 by engineers Dave Tasset and John Wendeln—both of whom brought nearly a decade of prior glass-to-metal sealing experience—HST has grown into a trusted partner for companies requiring precision and reliability in demanding environments.

From its early days, HST set itself apart by developing its own proprietary sealing glass, specifically engineered to meet the rigorous needs of the lithium battery market, including lithium thionyl chloride, lithium sulfur dioxide, and lithium magnesium dioxide chemistries. This innovation allowed HST to provide robust and reliable battery seals for applications ranging from oil exploration to military systems.

Building on that success, HST advanced its technology further with the development of its proprietary “Clean-Seal” process. This cutting-edge technique enables oxide-free sealing of challenging metals such as titanium, molybdenum, platinum-iridium, and stainless steel, without requiring chemical or mechanical post-sealing oxide removal. This was a game-changer—especially for the implantable medical battery market, where purity, consistency, and long-term hermeticity are absolutely essential. HST's titanium seals and power feedthroughs quickly gained a reputation for their superior performance in devices such as pacemakers, defibrillators, and neurostimulators.

The Clean-Seal Advantage offers numerous benefits:

Reliable, robust, and repeatable hermetic seals

No etching or chemical residues on glass or metal

Maintains material integrity by eliminating post-seal machining

Reduces risk of cracking, stress, or long-term failure

What truly differentiates HST is its unwavering commitment to quality. HST is the only glass-to-metal seal manufacturer that performs 100% leak testing on every seal, guaranteeing hermeticity to better than 1 x 10⁻⁸ cc/sec helium. This level of testing ensures unmatched product integrity and gives customers confidence that every part will perform reliably, even in the most extreme conditions.

HST works closely with its customers, offering engineering support and custom design assistance to ensure each product is optimized for performance and longevity. From prototype to production, HST partners with clients to meet the most demanding technical requirements while delivering exceptional value.

Products and services include:

Lithium Battery Seals

Welded Battery Lids

Titanium & Medical Battery Seals

Mil-Spec Type Sensor Seals

High Amperage Feedthroughs

Custom Hermetic Seals

With decades of experience, proven technology, and a hands-on engineering approach, HST continues to be a trusted name in hermetic sealing. Whether it's extreme downhole environments or lifesaving implantable devices, customers know they can count on HST.

When your technology depends on precision glass-to-metal seals, depend on Hermetic Seal Technology.