Silicone Rubber Material Guide: Types, Grades & How to Choose (VMQ, FVMQ, LSR, HTV & More)

Last Updated On: 2026-07-28

Silicone rubber comes in several types — VMQ for general sealing, FVMQ for oil and fuel, PVMQ for extreme cold, and processes like HTV and LSR for different volumes.

This guide explains every major type, when to use it, and how to choose the right one for your O-rings, gaskets, and custom parts.

One Material Family, Many Choices

“Silicone” is not one material. It is a family.

Two silicone O-rings can look identical — but one fails in oil within weeks, and the other lasts for years. The difference is the material type, the curing system, and the molding process.

This guide maps the whole family, so you can choose with confidence. Each section links to a full article on that topic.

Part 1: Material Types (The Base Rubber)

VMQ — Standard Silicone Rubber

The workhorse. When a drawing just says “silicone,” it means VMQ.

  • Temperature: -60°C to +200°C
  • Strengths: wide temperature range, weather and ozone proof, food-safe (platinum-cured)
  • Weakness: poor oil and fuel resistance, low tear strength
  • Best for: general O-rings, gaskets, food and medical seals

→ Full guide: What Is VMQ Silicone Rubber?

FVMQ — Fluorosilicone

Silicone that is not afraid of oil. Fluorine added to the polymer chain gives excellent oil, fuel, and solvent resistance.

  • Temperature: -60°C to +175°C
  • Strengths: oil resistance + silicone’s temperature range
  • Weakness: costs 3–5× more than VMQ, not food grade
  • Best for: fuel systems, automotive, aerospace seals

→ Full guide: Fluorosilicone (FVMQ): Oil & Fuel Resistant Silicone Explained

PVMQ & PMQ — Low-Temperature Silicone

Phenyl groups added to the chain keep the rubber flexible down to -100°C.

  • Best for: extreme cold — arctic equipment, aerospace, cryogenic-adjacent sealing
  • Trade-off: higher cost, slightly lower strength

Specialty Grades

Grade

What It Adds

Used For

Conductive silicone

Carbon or silver fillers

EMI shielding gaskets

Flame-retardant silicone

UL94 V-0 rating

Electronics, enclosures

Fiberglass-reinforced silicone

Fabric layer for strength

High-pressure gaskets, pads

Silicone foam / sponge

Closed-cell structure

Cushioning, thermal insulation

High-temperature grade

Heat stabilizers

Continuous 250°C applications

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Part 2: Curing Systems (How the Rubber Is Cross-Linked)

The same base silicone can be cured two ways:

Platinum-Cured (Addition Cure)

  • No by-products, no odor, higher purity
  • Required for FDA, USP Class VI, drinking water parts
  • Slightly higher material cost

→ Full guide: Platinum-Cured vs Peroxide-Cured Silicone

Peroxide-Cured

  • Lower cost, proven process
  • Slight odor and trace by-products (reduced by post-curing)
  • The economical choice for general industrial seals

Simple rule: touches food, water, or the human body → platinum. Everything else → peroxide is usually the smarter buy.

Part 3: Molding Processes (How Parts Are Made)

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→ Full guide: HTV vs LSR Silicone: Which Molding Process Fits Your Parts?

HTV / HCR — Solid Silicone

Solid rubber, compression or transfer molded.

  • Low tooling cost, flexible for small batches
  • Best for O-rings, gaskets, and low-to-medium volumes

LSR — Liquid Silicone Rubber

Two-part liquid, injection molded, always platinum-cured.

  • Very low cost per part at high volume
  • Best for small, complex, precise parts and medical-grade consistency

RTV — Room Temperature Vulcanizing

Cures without heat, usually applied as a paste. Used for form-in-place gaskets and on-site sealing — a different product category from molded parts.

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→ Full walkthrough with charts: Silicone O-Ring Material Selection Guide

Part 4: How to Choose — The 4-Step Method

Answer four questions and the right material picks itself:
1. What does the seal touch?
  • Air / mild environment → VMQ
  • Oil, fuel, solvents → FVMQ
  • Food, water, body → platinum-cured VMQ
2. How hot or cold?
  • -60°C to +200°C → any silicone
  • Below -60°C → PVMQ
  • Continuous steam → not silicone (ask about EPDM)
3. What certification do you need?
  • FDA / USP / EU food contact → platinum-cured
  • General industrial → peroxide-cured
4. How many parts?
  • Samples to ~50K → HTV compression molding
  • 100K+ and complex → LSR injection molding

Master Comparison Table

Options

VMQ

FVMQ

PVMQ

LSR (process)

Temperature

-60 to +200°C

-60 to +175°C

-100 to +180°C

Same as VMQ

Oil / fuel resistance

Poor

Excellent

Poor

Depends on base

Food / medical grade

Yes (platinum)

No

Yes (platinum)

Yes (standard)

Cost

Low

High

Medium–High

High tooling, low unit

Best volume

Any

Any

Any

100K+

Typical parts

O-rings, gaskets

Fuel seals

Cold-climate seals

Medical parts, micro parts

Tips from ZSR: Save this table. When a customer or colleague asks “which silicone?”, nine times out of ten the answer is already here.

Common Mistakes to Avoid

  • Writing “silicone” on a spec without the cure type or grade
  • Using VMQ where oil splash occurs — use FVMQ
  • Copying FKM specs into cold environments — FKM stiffens below -20°C
  • Buying LSR tooling for low-volume parts
  • Forgetting to specify hardness (70 Shore A is the safe default for O-rings)

FAQs

A: Silicon is a chemical element (used in chips). Silicone is the rubber made from it. The extra “e” matters.

A: Each wins somewhere. Silicone: widest temperature range, cleanest. EPDM: hot water and steam. NBR: cheap oil resistance. FKM: oil plus extreme heat. Match material to the job.

A: Yes. Translucent is natural; we match Pantone/RAL colors, including with FDA-compliant pigments.

A: In static sealing within their temperature range, often 10+ years. Silicone resists aging, ozone, and UV better than most rubbers.

A: We compound and mold VMQ and FVMQ in-house, in both HTV and LSR processes, peroxide or platinum cured. Send us your requirement.

Get Material Advice From the Manufacturer

ZSR is a silicone rubber manufacturer. We help engineers and buyers choose the right material before cutting any steel — free of charge.

Send your drawing, sample, or working conditions. Material recommendation and quote within 24 hours.

🔒 Your design and data are protected under NDA.

Prefer Email? Send Inquiry to [email protected]

In this guide series: What Is VMQ Silicone Rubber? · Fluorosilicone (FVMQ) Explained · Platinum-Cured vs Peroxide-Cured Silicone · HTV vs LSR Silicone · Silicone O-Ring Material Selection Guide