Specialists in Hermetics and Plating

Bulkhead Seals - Hermetic Seals - SGA Technologies

At SGA Technology we bring more than 50 years of experience and expertise to construct and supply high reliability bulkhead seals.

All design, production, plating and testing is conducted in-house by our team to the highest standards including ISO9001 and ISO14001.

We offer a range of bulkhead seals constructed for harsh environments across multiple applications and industries including Military Aerospace, Nuclear, Marine, Oil & Gas and Scientific measurement.

Our range of bulkhead seals includes:

Compression Seals

  • CTEshell > CTEglass > CTEcontact 
  • Relies on compressive mechanical stress to create a hermetic seal 
  • Excellent for high pressures of up to 20000psi or higher on request 
  • Good for temperatures up to 300oC applications or higher on request
  • Glass and pins under compressive stress by design 
  • Hermeticity usually tested to 1x10-8 atm.cc/sec max leak rate but can be tested up to 10-10 range if required 
  • Minimum shell wall/web thickness required to create enough compression on the glass 
  • Large variety of material to choose from: High CTE shell (stainless steels, Inconel, titanium etc.) means any glass (soda lime, borosilicate, glass ceramic) may be used. Contacts are typically Kovar, Nickel Iron alloys, molybdenum or composite contacts

Hybrid Seals

Compression/ME Hybrids

CTEShell1 > CTEglass1 ≥ CTEshell2 = CTEglass2 = CTEcontact 

Can be engineered to combines the benefits of both ME such as isolated coaxial options and compression seals to overcome design challenges. 

Hermeticity usually tested to 1x10-8 atm.cc/sec max leak rate but can be tested up to 10-10 range if required 

Limited material options for ME components but wider variety for outer shell materials

Composite pins seals

SGA has developed composite pin technologies to overcome high CTE material limitations in many applications, offering designers a wider choice of options. Techniques include:

  • Low-CTE material sleeving
  • High temperature brazing
  • Soldering
  • Welding

Custom Design Solutions 

SGA’s engineering team can offer custom designs and solutions for your high pressure bulkhead challenges. Customisation include, but are not limited to: 

  • Alternate materials and finishes 
  • Body and contact lengths and diameters 
  • Insert arrangements 
  • Higher or lower temperatures/pressures 
  • Lower leak rates to 10-10 (atm.cc/sec) range 
  • Higher insulation resistance and DWV rating
  • Single Glass vs Multi-glass Seals 

Single Glass Seals 

  • One glass per seal 
  • Easier to assemble which often means better price due to shorter handling times 
  • Higher pin density means more contacts per seal or smaller components are possible 
  • More insulator material between pins result in better insulation resistance 
  • Higher voltages possible for same size components compared to multi-glass seals 
  • Lower pressure capability compared to multi-glass variant 
  • Single glass preforms can be more costly depending on size

Multi-glass Seals 

  • Pins individually glassed in 
  • Assembly times can be longer than single-glass seals
  • Lower pin density for same size components 
  • Smaller insulator wall thicknesses between contacts and shell means lower insulation resistance for same part sizes compared to single-glass 
  • Ideal for very high pressure applications 
  • Lower voltage capabilities compared to single-glass 
  • Glass preforms tend to be cheaper for larger quantities depending on size

Do you need Over-moulding and Full Assembly?

From concept to final assemblies, SGA can offer a wide range of engineering solutions to your connection challenges including: 

  • Marine grade casting and over-moulding 
  • Resin and polymer potting 
  • Wire and Harnesses 
  • Soldering/Brazing 
  • Gold, Gold-Germanium soldering 
  • Resistance (spot) welded wire/features

Our Bulkhead Seals are precision-constructed and capable of sustaining high pressures (up to 20000 psi) and temperatures (-50oC to 150oC), with wider ranges available if required. Our units are designed and tested to MIL-STD’s for quality assurance, and offer high voltage and current capabilities subject to design.

Our Bulkhead Seals construction specifications include:

Machined Shells 

  • Lightweight material options for weight-critical applications 
  • Robust designs and materials for high pressure applications and extreme temperatures 
  • Glass to metal sealing 
  • Low temperature soldering (<450 degrees Celsius)
  • High temperature brazing (1000 degrees Celsius)

Machined shell materials include:

  • Kovar 
  • Stainless Steel (austenitic) 
  • Mild Steel 
  • Nickel Alloys 
  • Titanium 
  • Hastelloy 
  • Inconel

Contact Connections

We offer a diverse range of Contact connections including:

  • Straight contacts 
  • Solder cups 
  • Flats & tags 
  • Pronged ends 
  • Tubes Insulator options 
  • Barium-Alkali 
  • Borosilicate 
  • Glass-Ceramic 
  • Ceramics

Contact Materials include:

  • Kovar 
  • Nickel Iron alloys 48-52 (including Copper cored) 
  • Composite contacts (Low CTE material + Cu)
  • Hastelloy 
  • Platinum 
  • Nickel 
  • Molybdenum


Our seals include a flexible range of interconnects and coatings, all supplied in-house at no extra cost. Coatings we provide include:

  • Electroless and electrolytic Nickel 
  • Gold; hard acid, pure and immersion 
  • Tin/Lead; 60/40 
  • Tin: pure culmo, matt, reflowed as required 
  • Silver; fully bright electronic grade 
  • Copper; bright acid, cyanide & bright pyrophosphate 
  • Chemical Polishing; stainless steel, copper & brass

We pride ourselves on offering the highest quality components with optimal performance:

  • Hermeticity tested to 1x10-8 atm cc/sec (mbar litre/sec) as standard 
  • Can be supplied for ATEX and Mil-Std approval as required 
  • Suitable for temperature cycling, thermal shock, corrosion resistance etc. 
  • Compression construction for extended lifetime capability (25+ years) 
  • Tolerances, flatness, surface finishes and planarity to allow accurate interfacing and alignment.