Low Durometer Silicone Rubber
Low durometer silicone rubber is a soft, flexible elastomer that offers excellent sealing and cushioning performance in demanding environments. In engineering terms, “durometer” refers to a material’s hardness, typically measured on the Shore A scale for most silicone compounds. Standard silicone rubber is often in the range of 40–70 Shore A, but low durometer grades typically fall between 10–30 Shore A. This softness gives the material unique functional advantages for sealing, vibration control, and conformability.
ElastaPro makes low durometer silicone rubber as solid sheets and uncured compound. Contact us for a quote.
Material Characteristics of Soft Silicones
Low durometer silicone rubber is composed primarily of silicone polymer, reinforcing fillers, and curing agents. Because it’s less densely cross-linked than harder grades, it has a lower resistance to indentation and greater flexibility. It maintains key silicone properties—including thermal stability, UV and ozone resistance, and excellent electrical insulation—while adding the ability to deform easily under pressure. This makes it ideal for applications where a tight seal is required without high compressive forces.
Silicone’s temperature performance is another major benefit. Low durometer grades can typically operate between –60 °C and 200 °C, depending on the formulation. This allows them to remain soft and elastic in both high-temperature engine compartments and low-temperature aerospace or cryogenic applications. Their chemical resistance is also strong against water, weathering, and many common fluids.
Advantages of Low Durometer Silicone Rubber
The softness of low durometer silicone rubber allows it to conform to uneven or irregular mating surfaces. This reduces the need for extremely tight tolerances or surface finishes to achieve an effective seal. For engineers, this means design flexibility: surfaces can be less precise, yet sealing performance remains high.
Another key advantage is reduced compression set stress on mating components. Softer silicone exerts lower clamping force on plastic housings or lightweight structures, helping prevent warping, cracking, or fatigue over time. It can also compensate for tolerance stack-ups or surface imperfections more effectively than harder materials.
Vibration damping is another strength. Low durometer silicone can absorb and dissipate energy, making it useful for reducing vibration and noise in sensitive electronic assemblies or lightweight structures. It’s also often used to protect fragile components from shock.
Common Applications for Low Durometer Silicone Rubber
Engineers often specify low durometer silicone rubber for environmental seals, vibration isolators, and cushioning pads. It is commonly used in enclosures for electronics, including aerospace and defense systems, where soft seals maintain protection against moisture and dust. In medical devices, soft silicone is valued for patient comfort and gentle interface with skin or other sensitive materials.
Automotive engineers use it in gaskets and seals that must accommodate component movement or thermal expansion without leaking. It’s also popular in HVAC and lighting systems where sealing performance must remain reliable despite uneven surfaces or low clamping forces.
When to Use Softer Silicones
Low durometer silicone rubber is ideal when components are delicate, surfaces are irregular, or when maintaining a seal with minimal compression force is required. It’s also advantageous in environments with wide temperature fluctuations or when vibration damping is needed.
However, softer materials may not be appropriate where high mechanical strength or abrasion resistance is required. Engineers should balance softness with durability based on operating conditions.
In short, low durometer silicone rubber provides excellent sealing, flexibility, and environmental resistance—making it a versatile choice for many demanding applications where conformability and low stress are priorities.
Conductive Silicone Sheet FAQs
Conductive silicone sheet is a specialized elastomeric material designed to combine the flexibility and environmental resistance of silicone rubber with electrical conductivity. Unlike standard silicone, which is an electrical insulator, conductive silicone sheet is engineered by incorporating conductive fillers—typically carbon, silver, nickel, or other conductive particles—into the base silicone polymer. This creates a versatile material that provides reliable electrical grounding, electromagnetic interference (EMI) shielding, and electrostatic discharge (ESD) protection while maintaining the softness and resilience of silicone.
This article from ElastaPro provides answers to frequently asked questions (FAQs) about conductive silicone sheet.
What is the Material Composition and Structure of Conductive Silicone Sheet?
The base polymer is high-quality silicone rubber known for its thermal stability, weather resistance, and flexibility. Conductive performance is achieved by dispersing conductive particles throughout the silicone matrix. The type, size, and concentration of these fillers determine the sheet’s electrical properties, including volume resistivity and shielding effectiveness.
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Carbon-filled silicone provides moderate conductivity at a lower cost and is often used in general EMI shielding applications.
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Nickel-graphite filled silicone offers improved shielding and corrosion resistance.
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Silver-aluminum or silver-plated fillers provide the highest conductivity levels and are used in mission-critical applications such as aerospace or defense electronics.
The result is a sheet material that can function both as a gasket and as part of an electrical grounding or shielding system.
What are the Key Performance Characteristics?
Conductive silicone sheets maintain many of the physical advantages of standard silicone rubber. They can typically operate in temperatures ranging from –60 °C to 200 °C without losing flexibility or performance. They are resistant to UV exposure, ozone, and most environmental stressors, making them suitable for both indoor and outdoor use.
Electrical properties are a key differentiator. Depending on the formulation, conductive silicone can achieve volume resistivity levels low enough to meet EMI and ESD protection requirements for electronic enclosures. The material’s surface remains pliable, allowing it to maintain good electrical contact under low compression forces.
Another important characteristic is stability over time. Unlike some conductive coatings or films, conductive silicone maintains its performance through repeated compression cycles and environmental exposure.
What are the Advantages of Conductive Silicone Sheet?
For engineers, the main advantage is the ability to achieve both environmental sealing and electrical conductivity in a single material. Conductive silicone can replace the need for separate seals and conductive components, simplifying assembly and improving reliability.
Its softness and conformability allow it to create a reliable EMI shield even when mating surfaces are uneven or subject to tolerance variations. Because it exerts lower clamping forces than metal gaskets, it is particularly useful in lightweight enclosures or sensitive assemblies where excessive pressure could cause damage.
What are Some Common Engineering Applications?
Conductive silicone sheets are widely used to fabricate EMI gaskets, grounding pads, and conductive seals. They are frequently die-cut or waterjet-cut into custom shapes for electronic housings, communications equipment, aerospace and defense systems, and medical devices.
They are also used in equipment that must meet electromagnetic compatibility (EMC) regulations, such as shielding seams, joints, and access panels in electronic enclosures. Their thermal stability makes them suitable for use near heat-generating components without loss of conductivity.
When Do You Use Conductive Silicone Sheet?
Engineers should consider conductive silicone sheet when both environmental sealing and EMI/ESD protection are required. It is ideal for gasketing around electronic enclosures, especially in applications where weight, space, or assembly simplicity are concerns.
However, for extremely high current-carrying applications or where mechanical wear is high, metal-based solutions may be more appropriate.
In summary, conductive silicone sheet is a high-performance material that blends electrical conductivity with the proven reliability of silicone elastomers. For engineers, it offers a practical and efficient solution for EMI shielding and grounding applications in demanding environments.
Contact ElastaPro for conductive silicone sheet.
Sponge Silicone Sheet FAQs
Sponge silicone sheet is a lightweight, compressible, and resilient elastomeric material used in a wide range of engineering applications that require sealing, cushioning, insulation, or vibration control. Unlike solid silicone rubber, which has a dense structure, sponge silicone is characterized by a cellular matrix with either open or closed cells. This structure gives it a soft, compressible feel and allows it to conform easily to irregular surfaces while maintaining excellent sealing performance.
This article from ElastaPro answers frequently answered questions (FAQs) about this material
What are the Properties of Sponge Silicone Sheet?
Sponge silicone sheet is typically made from silicone rubber compounded with a blowing agent that creates a uniform cell structure during the curing process. Closed-cell sponge silicone has cells that are not interconnected, allowing it to resist water and fluid absorption. Open-cell sponge silicone, on the other hand, has interconnected pores, making it more breathable but less water resistant. Engineers choose between these types based on whether fluid sealing or air permeability is required.
One of the primary advantages of sponge silicone is its wide operating temperature range. Like other silicone elastomers, it typically performs well from –60 °C to 200 °C, depending on formulation. It remains flexible in cold environments and stable at elevated temperatures, making it suitable for harsh or fluctuating thermal conditions. Additionally, sponge silicone offers excellent resistance to ozone, UV exposure, weathering, and many chemicals.
What are its Advantages?
The compressibility of sponge silicone sheet allows it to form reliable seals with relatively low closure forces. This is particularly important in applications involving lightweight plastic or aluminum enclosures that could deform under excessive gasket pressure. The soft structure can compensate for uneven surfaces, tolerance stack-ups, or warped panels without sacrificing sealing integrity.
Sponge silicone also exhibits excellent recovery after compression, maintaining performance over many cycles. This resilience makes it a preferred choice for gasketing in environments where assemblies may be opened and closed repeatedly. Its low density also reduces weight compared to solid silicone, which can be a valuable advantage in aerospace, automotive, and portable electronic designs.
In addition to sealing, sponge silicone provides effective thermal insulation, vibration damping, and acoustic absorption. These properties make it useful in protecting sensitive components from shock, reducing noise transmission, and improving system reliability.
What are Some Common Applications?
Engineers specify sponge silicone sheet for a variety of applications across industries. It is commonly die-cut or waterjet-cut into gaskets and seals for electrical enclosures, HVAC systems, and outdoor lighting. In transportation and aerospace, it is used to seal access panels, doors, and hatches where flexibility and environmental resistance are critical.
Sponge silicone is also employed in thermal and acoustic management systems, acting as a buffer between vibrating or moving parts. In medical devices, its inertness and softness make it suitable for cushioning and sealing components.
When Do You Use Sponge Silicone Sheet?
Sponge silicone sheet is best used when a soft, conformable, and environmentally resistant material is needed to create a reliable seal under low compression forces. It’s ideal for enclosures exposed to temperature extremes, UV, or moisture. However, it is less abrasion-resistant and not suited for high mechanical wear situations.
In short, sponge silicone sheet combines the unique properties of silicone elastomers with the versatility of a compressible cellular structure. For engineers, it offers an effective solution for sealing, cushioning, and insulating applications where performance and durability must be balanced with softness and flexibility.
Contact ElastaPro for sponge silicone sheet.
What is Uncured Rubber?
Uncured rubber refers to rubber that has not yet undergone vulcanization or curing, the chemical process that crosslinks polymer chains to give rubber its final mechanical properties. In its uncured state, rubber is soft, pliable, and somewhat tacky. It resembles a dense, malleable putty or dough that can easily be shaped, extruded, or calendered into sheets or profiles.
At the molecular level, uncured rubber consists of long, entangled polymer chains that slide past each other when deformed. Because these chains are not chemically bonded, uncured rubber lacks the elasticity, tensile strength, and heat resistance that characterize cured elastomers. It is thermoplastic in behavior—softening with heat and stiffening when cooled—which allows it to be processed but not yet used as a finished engineering material.
Contact ElastaPro for uncured silicone rubber.
Composition and Processing of Uncured Rubber
Uncured rubber can be derived from either natural rubber (NR), harvested from latex sap, or synthetic rubbers such as silicone, EPDM, nitrile, or fluorocarbon. These raw elastomers are typically compounded with fillers (like carbon black or silica), plasticizers, stabilizers, and curing agents such as sulfur or peroxides.
During processing, uncured rubber is shaped into its desired form—extrusions, molded blanks, or sheets—before vulcanization. This stage is critical because once the rubber is cured, it becomes thermoset and cannot be reshaped without losing integrity. Engineers and manufacturers often handle uncured rubber in sheet, strip, or preform form, allowing for easy placement into molds or assemblies.
The Curing Transformation
The transition from uncured to cured rubber occurs through vulcanization, a heat-activated chemical reaction that introduces crosslinks between polymer chains. These crosslinks limit chain mobility, giving the material its characteristic elasticity and resilience.
For example, natural rubber is commonly cured with sulfur, producing a network structure that enhances mechanical strength, heat resistance, and chemical stability. Silicone rubber, by contrast, may use peroxide or platinum catalysts to achieve crosslinking. Once cured, the material becomes thermoset—meaning it will not melt or flow again when reheated.
Applications and Engineering Implications
Uncured rubber is used primarily as an intermediate material in manufacturing. Engineers and fabricators rely on its soft, conformable state for forming seals, gaskets, or molded parts before curing. It is also used in lamination or bonding processes, where it acts as an adhesive layer that cures in place during assembly.
In repair applications, uncured rubber patches or tapes can be applied to existing rubber components and then vulcanized to create a permanent bond. This approach is common in tire repair, conveyor belt maintenance, and industrial hose manufacturing.
What is Silicone Sheeting?
Silicone sheeting is a synthetic rubber commonly used in critical applications due to its exceptional heat resistance. It is also more versatile than other polymers because it retains pliability when exposed to ultraviolet radiation or extreme temperatures. Further, it is resistant to weathering and ozone, making it appropriate for various industrial purposes.
ElastaPro makes solid silicone sheet, foam silicone sheet, and sponge silicone sheet. We also make uncured silicone compound.
Silicone Sheeting Characteristics
The following are the characteristics of silicone sheeting
- Offers high resistance to UV radiation
- Possesses superior temperature resistance compared to synthetic and natural rubber
- Reacts to very few chemical or biological agents
- Maintains flexibility and elasticity regardless of weather conditions
- Made from high-grade compound materials
- Has tensile strength up to 1650 psi
- Insulates electricity well and is easily modifiable based on particular requirements
- Exhibits exceptional metal adherence, especially during molding and extrusion processes
- FDA-approved, making it safe for food and medical uses
Who Makes It?
ElastaPro makes silicone sheeting in a variety of durometers, sizes, thicknesses and colors. We offer specification grade materials, low minimum order quantities, quick lead times, and responsive service. To learn more, contact us.
50 Durometer Silicone Rubber
50 durometer silicone rubber represents a balanced midpoint—firm enough to maintain dimensional stability under compression, yet soft enough to conform to irregular surfaces and create effective seals. Engineers often specify 50 durometer silicone because it delivers an ideal combination of flexibility, resilience, and strength for a wide range of applications.
Contact ElastaPro for 50 durometer silicone rubber.
Understanding 50 Durometer Silicone
On the Shore A hardness scale, elastomers range roughly from 10 (extremely soft, gel-like) to 80 (very hard, nearly rigid). A 50 durometer silicone rubber falls in the medium range, providing a balance of mechanical and physical properties. It maintains excellent elasticity and rebound, offering a good compromise between sealing performance and durability.
Like all silicones, a 50 durometer compound maintains stable properties over a wide temperature range—typically from −60°C to +200°C—and resists ozone, UV radiation, and many chemicals. This makes it suitable for long-term use in both indoor and outdoor environments. It also exhibits low compression set, meaning it maintains its shape and sealing force even after repeated deformation cycles.
Ideal Applications
Engineers commonly use 50 durometer silicone rubber in general-purpose seals and gaskets. It provides sufficient resilience to form tight seals under moderate compression without requiring high closure forces. This makes it an excellent choice for flanged joints, enclosures, lighting housings, and HVAC systems, where sealing reliability and easy assembly are critical.
In electronic equipment, 50 durometer silicone sheets or gaskets act as protective barriers against dust and moisture, while maintaining electrical insulation and dielectric strength. The material’s flexibility allows it to fill surface gaps effectively, ensuring consistent contact across irregular geometries.
In automotive and aerospace applications, this hardness provides effective vibration isolation and resistance to environmental exposure. It is commonly used for engine compartment seals, access panel gaskets, and vibration mounts where the material must resist both heat and mechanical stress.
Additionally, medical-grade 50 durometer silicones are used for components such as pump diaphragms, valves, and tubing, where a balance between flexibility and mechanical integrity is needed. Food-grade versions are also available for processing and packaging environments where cleanliness and compliance with FDA or USP Class VI standards are mandatory.
Design and Performance Considerations
When selecting 50 durometer silicone rubber, engineers should consider operating pressure, compression percentage, and environmental conditions. For static sealing applications, optimal compression typically ranges from 15% to 25% of material thickness. This ensures adequate sealing force without overstressing the elastomer.
The material’s moderate hardness makes it easier to handle during fabrication—whether through die-cutting, molding, or extrusion—while maintaining dimensional stability during installation. However, for applications involving very low clamping force or extremely delicate components, softer silicones (30–40 Shore A) may perform better, while harder grades (60–70 Shore A) are preferred when greater structural support or load-bearing capacity is required.
Conclusion
Fifty durometer silicone rubber is a reliable, all-purpose material that strikes an excellent balance between softness and strength. Its combination of flexibility, temperature resistance, and sealing performance makes it one of the most widely used silicone grades across industries. Whether in electronics, aerospace, medical devices, or general manufacturing, engineers can count on 50 durometer silicone to provide consistent, long-lasting performance in demanding environments.
When you need a seal or component that can flex without failing and endure without hardening, 50 durometer silicone rubber is often the right choice.
Low Outgassing Silicones: Materials, Standards, and Applications
ElastaPro makes low outgassing silicones that meet ASTM E595 requirements and are specially formulated and processed to minimize the release of volatile compounds under vacuum conditions and/or heat. In addition to spacecraft, applications include aerospace, defense, electronics, optics, and medical devices.
ElastaPro produces low outgassing silicones at our Made in USA manufacturing facility in Santa Fe Springs, California and offers these specification grade materials as solid silicone sheet and uncured silicone compound. Choose ASTM E595 silicone in following durometers (hardness) on the Shore A scale: 40, 50, 60, and 70.
Keep reading to learn more and contact us for a quote.
What is Outgassing?
Outgassing refers to the release of volatile organic compounds (VOCs) from a material, typically at reduced pressure (vacuum) or elevated temperatures. Volatiles include residual solvents from processing, unreacted monomers, plasticizers and additives, and degradation products from thermal or environmental stress. Sometimes, outgassing is called off-gassing instead.
In vacuum conditions such as space, the released vapors from outgassing can condense on sensitive surfaces such as optical lenses, sensors, or electronics. This can cause contamination, but it can also degrade performance or result in mission failure. Silicone elastomers are chemically stable and heat resistant, but they can contain low-molecular-weight siloxanes that are prone to volatilization.
What is ASTM E595?
ASTM E595 defines a standard test method for Total Mass Loss and Condensable Volatile Materials from outgassing in a vacuum environment. ASTM International developed this test standard in cooperation with NASA, and it simulates the conditions that materials such as silicones may face when used aboard spacecraft.
Importantly, ASTM E595 provides a consistent, repeatable way to measure how much mass a material loses in avacuum due to outgassing, and how much of that lost mass condenses on nearby surfaces. There are three key metrics.
- Total Mass Loss (TML) is the percentage of initial mass lost by the specimen during the test. This measurement is important, but TML alone does not indicate contamination risk. Some volatiles may not condense on cold surfaces but dissipate harmlessly.
- Collected Volatile Condensable Material (CVCM) is the percentage of material that condenses on a cooled collector plate. CVCM is critical measurement for optical and thermal systems since even a small amount of condensable material can fog lenses, degrade solar panels, or alter thermal emissivity.
- Water Vapor Recovered (WVR) is an optional measurement for materials, such as silicones, that absorb and release water vapor. WVR is less critical in space environments, but it’s important for applications (such as electronic assembly) that may occur in humid conditions.
ASTM E595 provides the framework for measuring these values, but NASA’s own standards define acceptable limits for spacecraft. For example, NASA-STD-6016 specifies that a material must meet the following criteria to be considered low outgassing.
- TML ≤ 1.0%
- CVCM ≤ 0.10%
This dual structure of ASTM providing the test method and NASA providing the acceptance criteria ensures consistency and practical usability across the aerospace sector.
Where are Low Outgassing Silicones Used?
Low outgassing is important for spaceflight and aerospace applications, but engineers also need low outgassing silicones for electronics and semiconductors, medical devices and pharmaceuticals, and optical and precision instruments.
Aerospace and Spaceflight
Outgassed volatiles can condense on telescope mirrors, star trackers, and camera lenses, reducing transmission and resolution. These substances can also condense on thermal control surfaces such as radiators or solar arrays and alter emissivity and absorptivity. In crewed spacecraft, outgassed volatiles may pose toxicity or odor concerns.
Electronics and Semiconductors
In microelectronics, outgassed siloxanes can deposit on contacts or printed circuit boards, leading to insulation failure or corrosion. The low outgassing silicones that ElastaPro provides are used for enclosure sealing, but the electronics industry also needs materials with low levels of outgassing for potting compounds, conformal coatings, and encapsulants.
Medical Devices and Pharmaceuticals
ASTM E595 does not apply to medical devices or pharmaceuticals; however, these industries are also concerned about the migration of volatile compounds that could interfere with sterile environments or analytical equipment. Low outgassing silicones can help improve biocompatibility and analytical purity, but other standards and requirements also apply.
Optical and Precision Instruments
Microscopes, laser systems, and satellites all require pristine optical surfaces. Even trace condensation can cause scattering or absorption, degrading performance. Silicones with low outgassing may be required for these applications.
Ask Elasto Proxy for Low Outgassing Silicones
ElastaPro makes ASTM E595 silicone and supplies these specification grade materials as solid silicone sheet and uncured silicone compound. Solid silicone sheets arrive ready for die cutting and come in thicknesses ranging from .010” to .500” and widths up to 60”. Uncured silicone compound can be molded, extruded, or calendered.
At ElastaPro, we manufacture materials in accordance with our ISO 9001:2015 and AS9100D Certified Quality Management system (QMS) and provide a Certificate of Analysis (COA) with each batch for traceability. Contact us to request a quote, discuss your applications, or receive additional information about how we serve your industry.
Aerospace Silicones
ElastaPro makes aerospace silicones that meet customer callouts and military, civilian, and industry standards. These specification grade silicones are available as solid silicone sheet and uncured silicone compound. Solid silicone sheets arrive ready for die cutting and come in thicknesses ranging from .010” to .500” and widths up to 60”. Uncured silicone compound can be molded, extruded, or calendered.
ElastaPro manufactures aerospace silicones in accordance with our AS9100D and ISO 9001:2015 certified quality management system (QMS) at our Made in USA manufacturing facility in Santa Fe Springs, California. We are committed to meeting the highest quality standards and to supplying high-performance materials with the speed and value you deserve.
What are Aerospace Silicones?
Aerospace silicones are formulated to withstand the extreme conditions of aviation, aeronautics, and space. They differ from commercial grade and general purpose silicones in their enhanced properties such as high and low temperature resistance, durability, and low outgassing characteristics.
There are other silicone materials that can meet the rigors of extreme environments, but aerospace silicones also meet specifications from the U.S. military, civilian standards organizations, and/or original equipment manufacturers (OEMs). Some aerospace silicones are also military silicones, but not all military silicones are used in aerospace applications.
Types of Aerospace Silicones
ElastaPro makes aerospace silicones that meet the following specifications.
- A-A-55759
- A-A-59588
- AMS
- ASTM E595
- BMS
- DMS
- LMA
- MIL-DTL-25988
- MIL-PRF-81322
- MIL-SD-417
- PWA
- SAE
- WS14644
A-A-55759 Silicones
A-A-55759 silicones meet the requirements of alphanumeric classes within A-A-595750, a defense and aerospace specification from the U.S. General Services Administration (GSA) that is sometimes written as AA 59759, AA55759, or A A 55759. A-A-55759 has replaced ZZR765 (ZZ-R-75), which is still found on some part drawings.
ElastaPro makes the following types of A-A-55759 silicones.
- A-A-55759 1A
- A-A-55759 1B
- A-A-55759 3A
- A-A-55759 3B
A-A-59588 Silicones
A-A-59588 silicones meet the requirements of alphanumeric classes within A-A-59588, a defense and aerospace specification published by the U.S. General Services Administration (GSA) that is sometimes written as MIL SPEC AA-59588, AA 59588, AA59588, or A A 59588. This standard has replaced ZZR765 (ZZ-R-75), which is still found on some part drawings.
ElastaPro makes the following types of A-A-59588 silicones.
- A-A-59588 1A
- A-A-59588 1B
- A-A-59588 2A/2B
- A-A-59588 3A
- A-A-59588 3B
AMS Silicones
AMS silicones meet Aerospace Material Specifications (AMS) from SAE International. AMS standards are not military standards, but some military applications reference these civilian aerospace standards. In addition to material properties, AMS specifications cover manufacturing processes and testing procedures. They also include requirements for material selection and quality control.
ElastaPro makes the following types of AMS silicones and fluorosilicones.
- AMS3325
- AMS3326
- AMS3327
- AMS3332
- AMS3334
- AMS3335
- AMS3336
- AMS3337
- AMS3338
- AMS3345
- AMS3348
- AMS3349
- AMS3356
- AMS3357
- AMS3301
- AMS3302
- AMS3303
- AMS3304
- AMS3315
ASTM E595 Silicones
ASTM E595 silicones meet the low outgassing requirements in ASTM E595, which forms the basis of NASA’s low outgassing standard. These specification grade silicones have a total mass loss (TML) of ≤1.00% and a Collected Volatile Condensable Material (CVCM) of ≤0.10%. ElastaPro makes ASTM E595 silicones in 40, 50, 60, and 70 durometer (Shore A).
BMS Silicones
BMS silicones meet requirements in Boeing Material Specifications (BMS). The Boeing Company developed this set of standards to ensure that silicones and other materials meet specific performance and quality requirements for Boeing aircraft.
ElastaPro supplies BMS silicones that meet these specific standards.
DMS Silicones
DMS silicones meet Douglas Material Specification (DMS) requirements, which are now managed by The Boeing Company. Douglas developed these requirements to achieve efficient and cost-effective aircraft production through integrated processes, supplier compliance, quality management, and supply chain management.
Contact ElastaPro for DMS silicones.
LMA Silicones
LMA silicones meet Lockheed Martin Aeronautics (LMA) requirements. Lockheed Martin Aeronautics is a division of Lockheed Martin Corporation that focuses on the design, development, production, and sustainment of military aircraft. LMA maintains detailed specifications that define the required properties, testing methods, and quality control procedures for each material used.
ElastaPro makes silicones that meet LMA-ME025 and LMA-STM requirements.
MIL-DTL-25988 Fluorosilicones (AMSR-25988)
MIL-DTL-25988 fluorosilicones meet the requirements of a U.S. military detail (DTL) specification for fluorosilicone (FVMQ) elastomers that resist fuel and oil and are used in aerospace applications. MIL-DTL-25988 classifies materials into types, classes and grades based on properties such as tensile strength, elongation, and hardness.
AMSR25988, an SAE International specification, supercedes MIL-DTL-25988; however, MIL-DTL-25988 is still found on part drawings. AMSR25988 and MIL-DTL-25988 both supercede the MILR-25988 standard, which is sometimes written as MIL-R-25988. Applications for MIL-DTL-25988 fluorosilicones include O-rings, molded parts, sheets, strips, and extruded shapes.
Contact ElastaPro for MIL-DTL-25988 fluorosilicones.
MIL-PRF-81322 Silicones
MIL-PRF-81322 silicones conform to a U.S. Department of Defense performance specification (PRF) for aircraft turbine engine lubricating oils. MIL-PRF-81322 does not focus specifically on silicone, but some lubricants contain silicone-based additives. Silicones contribute to a lubricant’s ability to withstand the high temperatures from turbine engines.
Contact ElastaPro for MIL-PRF-81322 silicones.
MIL-STD-417 Silicones
MIL-STD-417 silicones conform to a U.S. Department of Defense standard (STD) that defines a classification system and test standard for solid elastomeric materials (vulcanized rubber compounds). Material designations under this standard begin with the letter TA and are followed by a three-digit numeric identifier.
ElastaPro makes MIL-STD-417 silicones rangng from TA 405 to TA 810.
PWA Silicones
PWA silicones meet Pratt & Whitney requirements. Pratt Whitney, a division of RTX, designs and builds engines that are used aboard military and civilian aircraft. Compliant silicones must conform to AMS standards, military specifications, and other industry standards in addition to Pratt & Whitney’s internal requirements.
Contact ElastaPro for PWA silicones.
SAE Silicones
SAE silicones meet specific standards from SAE International. AMS silicones and AMS-R-25988 silicones meet SAE standards, but there are other standards that affect silicones as well. For example, SAE-J20 covers silicone rubber that’s used in coolant hoses. TS147 covers silicone that used in loop-style clamp assemblies.
In addition to AMS and AMSR-25988 silicones, ElastaPro makes SAE-J20 and TS147 silicones.
WS14644 Silicones
WS14644 silicones are used in but not limited to aerospace applications. They meet the requirements of a U.S. Department of Navy specification that establishes requirements for vulcanized electrically conductive rubber compounds. WS14644 contains three types of materials and is sometimes listed on older part drawings.
ElastaPro makes Type III WS14644 silicones that are filled with carbon black and provide high conductivity.
Ask ElastaPro for Aerospace Silicones
ElastaPro makes specification grade aerospace silicones and supplies these materials as solid silicone sheet and uncured silicone compound. We provide a Certificate of Analysis (COA) with each batch for traceability. Contact us to request a quote, discuss your applications, or receive additional information about how we serve the aerospace industry.
USP Class VI Sealing Products: Seven Types
USP Class VI sealing products encompass a broad spectrum of geometries, materials, and manufacturing approaches. From simple O-rings and gaskets to complex diaphragms, valve seats, and custom molded parts, these seals play a critical role in ensuring product safety, regulatory compliance, and reliable performance in high-purity environments. Engineers selecting these seals must carefully evaluate sterilization resistance, chemical compatibility, and extractables, all while aligning with industry-specific regulatory frameworks.
ElastaPro makes USP Class VI silicone materials as solid silicone sheet and uncured silicone compound. For service, quality, value and speed, contact ElastaPro.
Types of USP Class VI Sealing Products
There are seven major types of USP Class VI sealing products.
- O-rings
- Gaskets
- Diaphragms
- Sealing Profiles and Extrusions
- Sanitary Seals and Tri-Clamp Gaskets
- Custom Molded Sheets
- Valve Seats and Sealing Components
The following sections describe them.
1. O-Rings
O-rings are the most common and versatile USP Class VI sealing products used in biomedical and pharmaceutical equipment.
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Materials: USP Class VI–certified elastomers such as silicone, fluorosilicone, EPDM (ethylene propylene diene monomer), and FKM (fluoroelastomer). Silicone and EPDM are especially common due to their chemical resistance and cleanroom compatibility.
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Applications: O-rings are used in syringe pumps, bioreactors, peristaltic pumps, chromatography systems, and aseptic connectors. Their circular geometry provides uniform compression and reliable sealing even under pressure cycling.
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Key Benefits: Ease of installation, broad chemical compatibility, and resistance to sterilization methods such as autoclaving, gamma irradiation, and ethylene oxide (EtO) treatment.
2. Gaskets
Gaskets provide flat sealing between two rigid surfaces, typically flanges.
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Materials: USP Class VI silicone sheets, PTFE (polytetrafluoroethylene) composites, and perfluoroelastomers (FFKM). PTFE-encapsulated silicone gaskets are often specified when chemical resistance and biocompatibility are both required.
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Applications: Sterile process piping, pharmaceutical mixing tanks, bioprocessing skids, and clean-in-place (CIP) systems. In these environments, gaskets prevent contamination and maintain sterile boundaries.
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Key Benefits: Large sealing surface, customizable geometry, and high resistance to process fluids ranging from solvents to biological media.
3. Diaphragms
Diaphragms are flexible membranes that separate two environments while allowing pressure or mechanical force to be transmitted.
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Materials: USP Class VI–approved silicone, EPDM, or PTFE-lined elastomers. Some diaphragms are multilayer composites that combine flexibility with chemical inertness.
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Applications: Diaphragm valves, pump heads, and pressure regulators in biopharmaceutical systems. They are especially critical in applications where sterility and purity must be maintained without direct fluid leakage.
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Key Benefits: Smooth, crevice-free geometry that reduces bacterial entrapment; compatibility with sterilization; and long fatigue life under cyclic loading.
4. Sealing Profiles and Extrusions
Custom sealing profiles, sometimes referred to as extruded seals, are widely used in pharmaceutical isolators, medical enclosures, and sterile filling equipment.
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Materials: USP Class VI silicone rubber is the dominant choice due to its flexibility, clarity (in translucent grades), and resistance to repeated sterilization. Thermoplastic elastomers (TPEs) are also used in some extrusion profiles.
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Applications: Door seals in cleanrooms, chamber gaskets for lyophilizers, and perimeter seals for glove boxes. They maintain controlled atmospheres and prevent ingress of contaminants.
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Key Benefits: Continuous lengths with minimal splicing, availability in bulb, U-channel, and custom geometries, and low compression set for long-term sealing.
5. Sanitary Seals and Tri-Clamp Gaskets
Sanitary seals are standardized USP Class VI sealing products used with hygienic fittings in biopharma and food processing.
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Materials: USP Class VI silicone, EPDM, FKM, and PTFE. Some manufacturers also provide platinum-cured silicone versions, which reduce extractables compared to peroxide-cured variants.
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Applications: Tri-clamp gaskets seal the joints in stainless-steel sanitary tubing systems. They are indispensable in dairy processing, vaccine production, and parenteral drug manufacturing.
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Key Benefits: Easy assembly and disassembly for cleaning, compliance with both USP Class VI and FDA CFR 21, and surface finishes optimized for cleanability.
6. Custom Molded Seals
Not all sealing requirements can be met with standard geometries. Custom molded USP Class VI sealing products allow engineers to create shapes tailored to specific equipment.
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Materials: USP Class VI elastomers including silicone, EPDM, and perfluoroelastomers. These can be compounded to balance mechanical properties with biocompatibility.
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Applications: Seals for implantable devices, diagnostic cartridges, microfluidic platforms, and drug delivery systems. Custom seals often support innovations in life sciences where unique geometries are required.
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Key Benefits: Optimized sealing performance, integration with device architecture, and scalability for high-volume production.
7. Valve Seats and Sealing Components
Beyond diaphragms, valve systems often require additional USP Class VI–compliant sealing parts such as valve seats, poppets, and bellows.
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Materials: PTFE, perfluoroelastomers, or high-purity silicone. Material selection depends on chemical exposure and mechanical requirements.
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Applications: Aseptic sampling valves, pinch valves, and dosing systems in sterile pharmaceutical manufacturing.
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Key Benefits: High wear resistance, low extractables, and reliable sealing under dynamic movement and pressure cycling.
Do you need USP Class VI silicones to fabricate products like these ? Contact ElastaPro.
Silicone Colors: The Most Popular Choices for Silicone Sheet
- Black
- White
- Red
- Blu
- Orange
- Gray
- Clear
- Transparent
- Translucent
Contact us for more information, including custom silicone colors!
Black Silicone Sheet
White Silicone Sheet
White silicone sheets are used for a wide range of applications, including in the food industry for baking mats and conveyor belts, in medical settings for device seals and protective covers, in home appliances for insulation, and in various industrial applications for gaskets, seals, and insulation due to its non-toxicity, flexibility, and resistance to extreme temperatures. Aesthetically, white silicone is often chosen for its clean appearance in kitchens, bathrooms, and for sealing glass curtain walls in construction.
