The Complete Guide to Silicone Rubber Grades and Their Uses  

Every industry relies on materials that can perform reliably under pressure, and silicone excels because it can be engineered in many forms, densities, and performance levels. These extruded silicone rubber grades are designed to solve different challenges, from heat resistance and cushioning to purity, conductivity, and fire safety.

As products become more advanced and regulations get stricter, choosing the right silicone grade has become essential for engineers, designers, and manufacturers.

In this guide, we break down the major grades, their characteristics, and how to select the best fit for your application.

Understanding Silicone Rubber Grades

Custom Silicone isn’t a single material; it exists in multiple formulations, densities, and performance levels, which engineers refer to as silicone rubber grades. Each grade is created to solve a specific functional need, such as cushioning, heat resistance, chemical stability, conductivity, or food and medical compliance.

These different silicone grades range from soft sponge materials to firm solid compounds, as well as highly specialized variants such as flame-retardant, FDA-compliant, electrically conductive, or aerospace certified grades.

Standards such as AMS, ASTM D1056, AA-59588, UL94, and RMA tolerance classifications help engineers identify the exact material properties required for each application.

Choosing the Right Silicone Rubber Grade for Your Application

Selecting the right material starts with choosing a silicone rubber grade that matches your operating conditions. Each application requires a specific performance profile, temperature, movement, chemical requirements, or regulatory requirements.

Key Things to Consider

• Temperature limits — high heat, freezing, or cycling.
• Mechanical needs — soft, medium, or firm density.
• Chemical contact — oils, fuels, solvents.
• Compliance — silicone for medical use, pharma purity.
• Hygiene — FDA-approved food-grade silicone.
• Industry environment — vibration or heat for automotive silicone.
• Electrical behavior — insulating or conductive.
• Fire rating — UL94 requirements.

Quick Industry Match

• Medical: platinum-cured, biocompatible grades.
• Food & beverage: FDA white food-grade silicone.
• Automotive: durable, heat-resistant automotive silicone.
• Electronics: conductive or flame-retardant grades.
• Aerospace: certified high-performance materials.

Also Read – Silicone Rubber: What Grades Are Available?

Key Characteristics of Different Silicone Grades

Each silicone type performs differently based on density, purity, reinforcement, or certification.

Below is a clear breakdown of the characteristics of silicone grades offered by Elastostar.

A. Silicone Sponge Grades

• AMS 3195 Medium Silicone Sponge
  Medium-density, reliable cushioning; closed-cell structure for controlled compression.
  
• AMS 3196 Firm Density Closed-Cell Silicone Sponge
  Firm, strong sealing pressure, ideal for demanding industrial environments.
  
• ASTM D1056 Soft Silicone Sponge
  Soft density for gentle sealing, vibration damping, and lightweight insulation.
  
• Commercial Grade Silicone Sponge Rubber
  Cost-effective, versatile option for general sealing and gasketing needs.

B. Solid Silicone Grades

• Solid FDA Grade White
  Safe for direct food contact; maintains purity and stability in processing environments.
  (Perfect where durable silicone + hygiene is required.)
  
• Solid Silicone Electrically Conductive Grade
  EMI/RFI shielding, anti-static components, and electronic protection.
  
• Solid Silicone Fibreglass Reinforced Grade
  Added strength and tear resistance for high-stress applications.
  
• Solid Silicone ZZ-R-765 / AA-59588 Grade
  Military/aerospace certified material with strict tolerance and performance requirements.
  (A true high-performance silicone grade.)

C. Flame-Retardant Sponge Grades

• UL 94 HB Silicone Sponge
  Basic flame resistance for lower-risk applications.
  
• UL 94 V-0 Silicone Sponge
  Self-extinguishing, superior fire protection for electronics, EV, aviation, and public-safety systems.

D. Tolerance & Material Reference

• RMA Precision Tolerance Grades
  Defines exact dimensional accuracy for extruded and molded silicone parts.
  
• Silicone Material Overview
  General performance insight across all densities, hardness levels, and temperature ranges.
  (Shows where heat-resistant silicone or specialty formulations fit.)

Also Read– High-Temperature Rubber Grades: Properties & Testing

Silicone Rubber Grades

What are the Applications of Various Silicone Rubber Grades?

Different silicone grades are selected based on the performance demands of each industry.
Here are the most common applications of silicone grades across key sectors.

1. Medical & Pharmaceutical

Best grades:

• Solid FDA Grade White.
• ASTM D1056 Soft Silicone Sponge.
• AA-59588 / ZZ-R-765 Grade.

Used for:

• Seals and gaskets in sterile equipment.
• Silicone for medical devices.
• Fluid control systems.
• Lab instruments.

These grades offer purity, biocompatibility, and stability during sterilization.

2. Food & Beverage Processing

Best grades:

• Solid FDA Grade White.
• Closed-cell sponge grades (AMS 3195 / AMS 3196).

Used for:

• Food-safe gaskets.
• Processing equipment seals.
• High-temperature oven and conveyor components.

Perfect where hygiene and heat resistance are essential.

3. Automotive & EV Systems

Best grades:

• AMS 3195 / AMS 3196.
• Fibreglass Reinforced Silicone.
• AA-59588 / ZZ-R-765 Grade.

Used for:

• High-heat engine sealing.
• EV battery insulation.
• Vibration damping.
• Hose and gasket components.

These provide silicone for automotive environments where durability and heat stability matter.

4. Aerospace & Defense

Best grades:

• UL94 V-0 Flame-Retardant Sponge.
• AA-59588 / ZZ-R-765 Grade.
• Fibreglass Reinforced Silicone.

Used for:

• Fire-safe cabin seals.
• High-altitude gaskets.
• Thermal insulation.
• Vibration control.

Aerospace depends on certified high-performance silicone.

5. Electronics, Sensors & Electrical Equipment

Best grades:

• Electrically Conductive Silicone.
• UL94 HB / UL94 V-0 Grades.

Used for:

• EMI/RFI shielding.
• ESD protection.
• Sensor housings.
• Electronic enclosure gaskets.

These grades support electrical safety and flame resistance.

6. Industrial Machinery & High-Temperature Equipment

Best grades:

• AMS 3196 Firm Sponge.
• Commercial Sponge Grade.
• High-strength reinforced solid silicone.

Used for:

• Oven sealing.
• Furnace systems.
• Heat tunnels.
• Mechanical insulation.

Perfect for applications exposed to continuous heat, pressure, or movement.

7. Construction & Architectural Sealing

Best grades:

• Soft to medium sponge grades.
• Commercial sponge silicone.

Used for:

• Weather seals.
• Window glazing gaskets.
• Expansion joint filling.
• Outdoor gasketing.

Weather-stable materials ensure long service life in building applications.

Why Choose Elastostar Rubber Corporation for Silicone Rubber Grades?

As a leading silicone rubber manufacturer, we produce high-precision materials that meet AMS, ASTM D1056, AA-59588, UL94, FDA, and USP Class VI (Sections 87 & 88) standards. Our team supports engineers with reliable materials and fast turnaround.

What You Can Expect?

• Custom extruded profiles, O-rings, gaskets & sheet materials.
• Reverse engineering, prototyping & production support.
• Shortest lead times from our large U.S. facility.
• Tailored hardness, density, color & reinforcement options.
• Guidance for heat, chemical, movement & compliance needs.

Proudly Made in the USA, we deliver silicone grades built for durability, stability, and long service life.

Recommended Reads

1. Silicone Rubber Compounds: Meaning, Properties & Applications
2. What Is the Importance of UL Rating for Silicone Rubber?
3. FDA Silicone Meaning: Properties & Considerations

Conclusion

Selecting the right silicone rubber grade is essential for achieving reliable sealing, durability, and long-term performance in demanding applications. With options ranging from sponge and solid grades to FDA-approved, conductive, flame-retardant, and aerospace-certified materials, silicone can be precisely matched to temperature, chemical, and regulatory requirements across industries.

Understanding these differences helps engineers choose materials that perform consistently and meet safety standards. For guidance on selecting the best grade for your project, contact Elastostar Rubber Corporation. Our team can help you identify the ideal material for your design and application needs.

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