Product Overview
Reliable custom rubber parts for industrial applications
Quick Answer
This red silicone O-ring assortment is designed for industrial sealing, maintenance kits, repair kits and assembly programs requiring multiple O-ring sizes. Inner diameter, cross-section, Shore A hardness, dimensional tolerance, size quantity, packaging and labeling can be customized. RoHS, REACH and FDA documentation options are available for applicable silicone compounds.
Red Silicone O-Ring Assortment — VMQ High-Temperature Industrial Seal Kit, ISO 3601 / AS568A, FDA Grade
This red silicone O-ring assortment includes multiple circular elastomer seals for static and selected dynamic sealing applications. Each O-ring is designed for groove installation and controlled compression between compatible mating components. Red silicone offers flexible sealing behavior for applications requiring temperature stability, clean appearance and clear visual identification. Sizes, hardness, packaging and compliance requirements can be customized.
Product Overview
The red silicone O-ring assortment is designed for industrial sealing applications where multiple O-ring sizes are required for assembly, maintenance, repair or distributor inventory. Each O-ring has a circular shape with a round cross-section and is installed in a groove to seal between two compatible surfaces. Silicone rubber is often selected when flexibility, temperature stability and visual identification are important. The red color helps distinguish silicone O-rings from black NBR or EPDM seals during storage and installation. The assortment can be supplied according to standard size references, customer drawings, equipment service kits or customized size lists. Final selection depends on groove design, media contact, pressure, temperature and compression requirements.
| Attribute | Value |
|---|---|
| Product Name | Red Silicone O-Ring Assortment |
| Material | VMQ (Polydimethylsiloxane — Silicone Rubber) |
| Color | Red / Brick Red (iron oxide pigmented — visual identification standard) |
| Hardness | Shore A 70 (standard); Shore A 40 / 50 / 60 / 80 available |
| Standard Series | ISO 3601 Metric; AS568A Imperial (BS 1806, DIN 3771, JIS B2401 cross-reference) |
| Cross-Section (CS) Range | 1.0 mm, 1.5 mm, 2.0 mm, 2.4 mm, 3.0 mm, 3.5 mm, 4.0 mm, 5.0 mm, 6.0 mm, 7.0 mm |
| ID Range | 1.5 mm to 300 mm (standard assortment); up to 2,000 mm lathe-cut |
| Temperature Range | -60°C to +250°C continuous; short-term peaks to +300°C |
| Pressure Rating | Static: up to 80 bar; Dynamic: up to 30 bar (no back-up ring) |
| Fabrication | Compression moulding; injection moulding; lathe-cut (large diameter) |
| Assortment Kit Options | 225-piece metric kit (15 sizes); 382-piece kit (30 sizes); custom BOM kits |
| Certifications | FDA 21 CFR 177.2600; RoHS; REACH; NSF/61 available; USP Class VI available |
Why Red? — The Color Coding Convention for Silicone O-Rings
The red color of silicone O-rings is not arbitrary — it is an internationally recognized material identification convention followed by O-ring manufacturers worldwide. In any mixed-compound workshop environment, visual compound identification before installation is critical: installing an NBR O-ring in a steam service application or an EPDM O-ring in an oil-contact application causes immediate or rapid seal failure. The industry color coding system provides instant visual identification:
| Color | Compound | Primary Application |
|---|---|---|
| Black | NBR (standard) | Oil, hydraulic fluid, fuel |
| Black | EPDM | Water, steam, outdoor |
| Red / Brick Red | VMQ Silicone | High temp, food, pharma |
| Brown | FKM (Viton®) | Chemical, high temp oil |
| White / Translucent | VMQ Silicone (natural) | Food, medical, clean |
| Blue | VMQ Silicone (food grade) | Food processing (metal-detectable) |
| Yellow / Green | FFKM | Extreme chemical service |
Red VMQ silicone O-rings are immediately identifiable by any technician — a critical safety feature in industries where compound mix-up causes equipment failure, contamination incidents, or process shutdowns.
VMQ Silicone — Material Properties in Detail
Silicone rubber (VMQ — Vinyl Methyl Siloxane) is fundamentally different from carbon-chain elastomers such as NBR, EPDM, and FKM. The Si-O-Si (siloxane) backbone of VMQ has the highest bond energy of any polymer backbone used in rubber manufacture — the molecular basis for VMQ’s outstanding thermal stability, wide temperature range, and chemical inertness.
Temperature Performance — The Primary Advantage
VMQ silicone O-rings maintain full elastic functionality from -60°C to +250°C continuous — a 310°C operating window no other standard O-ring material approaches:
| Compound | Lower Temp Limit | Upper Temp Limit | Operating Window |
|---|---|---|---|
| VMQ Silicone | -60°C | +250°C | 310°C |
| FKM (Viton®) | -20°C | +200°C | 220°C |
| EPDM | -50°C | +150°C | 200°C |
| HNBR | -40°C | +150°C | 190°C |
| NBR | -40°C | +100°C | 140°C |
| CR (Neoprene) | -40°C | +120°C | 160°C |
At -60°C, where all other rubber compounds have hardened to glass-like rigidity, VMQ silicone remains flexible and elastic — maintaining sealing contact stress and preventing cold-leak failure at cryogenic process temperatures. At +250°C continuous, VMQ retains sufficient elasticity and compression set resistance to maintain static sealing integrity in sustained high-temperature industrial applications.
FDA Compliance — The Critical Food & Pharma Advantage
VMQ silicone is the compound of choice for food, beverage, and pharmaceutical O-ring applications because:
FDA 21 CFR 177.2600 — the US FDA regulation governing rubber articles in contact with food; standard-grade red VMQ silicone satisfies this regulation
- EU Regulation (EC) 1935/2004 — European food contact materials regulation; VMQ compliant
- USP Class VI — US Pharmacopeia biological reactivity standard for implant and pharmaceutical contact; VMQ available in USP Class VI grade
- NSF/61 — US drinking water system component standard; VMQ available in certified grade
- Silicone does not impart taste, odor, or color to food or beverage products — critical for process equipment in direct food contact
- Silicone is resistant to CIP (clean-in-place) and SIP (steam-in-place) sterilization chemicals including NaOH, HNO₃, and steam at +135°C
Key Physical Properties (Shore A 70 Red VMQ)
| Property | Test Method | Value |
|---|---|---|
| Hardness | ISO 48-4 / Shore A | 70 ± 5 |
| Tensile Strength | ISO 37 | ≥ 6.5 MPa |
| Elongation at Break | ISO 37 | ≥ 200% |
| Compression Set | ISO 815 (22h @ 175°C) | ≤ 25% |
| Tear Strength | ISO 34-1 | ≥ 15 kN/m |
| Volume Change in Water | ISO 1817 (70°C, 24h) | ≤ +3% |
| Heat Aging | ISO 188 (70h @ 200°C) | ≤ ±15% property change |
| Low-Temp Flexibility | ISO 812 | -60°C (no cracking) |
| Density | ISO 2781 | 1.15–1.25 g/cm³ |
| Temperature Range | Continuous service | -60°C to +250°C |
Standard Individual Size Reference (ISO 3601 Metric, Red VMQ 70A)
| ID (mm) | CS (mm) | OD (mm) | ISO Designation |
|---|---|---|---|
| 1.5 | 1.0 | 3.5 | — |
| 3.0 | 1.5 | 6.0 | G3 |
| 5.0 | 1.5 | 8.0 | G5 |
| 8.0 | 1.5 | 11.0 | G8 |
| 10.0 | 2.0 | 14.0 | G10 |
| 15.0 | 2.5 | 20.0 | G15 |
| 20.0 | 2.5 | 25.0 | G20 |
| 25.0 | 3.0 | 31.0 | G25 |
| 30.0 | 3.0 | 36.0 | G30 |
| 40.0 | 3.5 | 47.0 | G40 |
| 50.0 | 4.0 | 58.0 | G50 |
| 75.0 | 5.0 | 85.0 | G75 |
| 100.0 | 5.0 | 110.0 | G100 |
| 125.0 | 6.0 | 137.0 | G125 |
| 150.0 | 6.0 | 162.0 | G150 |
| 200.0 | 7.0 | 214.0 | G200 |
| 250.0 | 7.0 | 264.0 | G250 |
| 300.0 | 8.0 | 316.0 | G300 |
Red vs. Other VMQ Silicone Colors — When to Specify Each
| Color | Grade | Key Differentiator | Best Application |
|---|---|---|---|
| Red (this product) | Industrial VMQ 70A | Universal visual ID; FDA compliant | Industrial sealing, food processing, HVAC, automotive |
| Translucent / White | FDA VMQ | Maximum purity; no pigment migration risk | Pharmaceutical direct contact, medical devices |
| Blue (metal-detectable) | FDA VMQ + metal-detectable filler | Detectable by X-ray and metal detector | Food processing — contamination control |
| Black | Carbon-black VMQ | Higher UV resistance | Outdoor exposed silicone seals |
| Green | Coloured VMQ | Custom compound identification | OEM proprietary color coding |
For most industrial applications, red VMQ 70A is the correct and most cost-effective specification. White translucent is specified only where pigment migration to product is a concern — typically direct pharmaceutical product contact.
Application Markets
Food & Beverage Processing
The largest application market for red VMQ silicone O-rings. Direct food-contact sealing in filling machines, pasteurizers, homogenizers, heat exchangers, pump covers, valve stems, and pipeline connectors requires FDA-compliant O-rings that resist both the food product media and the aggressive CIP and SIP cleaning and sterilization chemicals. Red VMQ at Shore A 70 covers:
- Dairy processing (pasteurizers, separators, fillers)
- Beverage bottling and canning equipment
- Brewing and fermentation vessel seals
- Confectionery and baking equipment
- Edible oil processing
Pharmaceutical & Biotech
VMQ silicone O-rings in USP Class VI or ISO 10993 certified grade seal bioreactors, WFI water system flanges, sterile filling equipment, autoclave door seals, and pharmaceutical pipeline connections. The compound’s resistance to steam sterilization (SIP at +135°C) and CIP chemical cycles combined with extractables and leachables profiles acceptable for pharmaceutical contact make it the material of first choice in regulated pharma and biotech production environments.
Automotive — Engine, Exhaust & Thermal Systems
VMQ silicone O-rings are specified throughout automotive engine and exhaust systems where operating temperatures exceed NBR’s +100°C ceiling. Applications include:
- Turbocharger intercooler hose connections (+150°C to +200°C)
- Engine coolant system connections
- Exhaust gas recirculation (EGR) valve seals (+200°C+)
- Transmission and gearbox high-temperature seals
- Diesel particulate filter (DPF) connections
HVAC & Refrigeration
HVAC equipment with high-temperature heat exchanger connections, steam heating coil seals, and refrigeration system O-rings at very low evaporator temperatures benefit from VMQ’s wide temperature capability. Red VMQ O-rings are specified in direct-expansion refrigeration systems (evaporator temperatures down to -40°C) and high-temperature heat exchanger connections simultaneously within the same equipment.
Industrial Process Equipment
Chemical process reactors, heat exchangers, and industrial ovens with operating temperatures above +150°C require O-ring compounds beyond EPDM and NBR capability. Red VMQ silicone O-rings provide reliable static sealing in:
- Industrial oven and furnace door seals
- Heat exchanger cover gaskets and port seals
- Steam sterilizer (autoclave) door seals
- Textile and paper drying equipment
- Plastics processing and extrusion equipment
Electrical & Electronics
VMQ silicone’s inherent electrical insulating properties, wide temperature range, and UL94 V-0 flame retardancy (in specific formulations) make red silicone O-rings the sealing choice for:
- Electrical enclosure cable entry glands
- Connector body environmental seals (IP67/IP68)
- LED lighting fixture weather seals
- High-voltage transformer and switchgear seals
- Industrial sensor and transducer body seals
VMQ vs. Other Compounds for High-Temperature Applications
| Criterion | VMQ (Red) | EPDM | FKM (Brown) | HNBR |
|---|---|---|---|---|
| Max continuous temp | +250°C | +150°C | +200°C | +150°C |
| Min temp | -60°C | -50°C | -20°C | -40°C |
| FDA compliance | ✅ Standard | ✅ Available | ✅ Available | ❌ |
| Water / steam | ✅ Good | ✅ Excellent | ✅ Good | ❌ |
| Oil resistance | ❌ Poor | ❌ Poor | ✅ Excellent | ✅ Excellent |
| Chemical resistance | ✅ Good | ✅ Good | ✅ Outstanding | ✅ Good |
| CIP/SIP resistance | ✅ Excellent | ✅ Good | ✅ Good | ❌ |
| Color ID | Red | Black | Brown | Black |
| Relative cost | Medium | Low | High | Medium |
Groove Design Reference for VMQ Silicone O-Rings
VMQ silicone has lower tensile strength and tear resistance than NBR or FKM. This requires slightly wider groove clearance gaps and more careful surface finish control to prevent extrusion and installation damage:
| Application | Recommended Squeeze | Groove Surface Finish | Max Pressure (no back-up) |
|---|---|---|---|
| Static face seal | 20–25% | ≤ 3.2 μm Ra | 80 bar |
| Static radial seal | 15–22% | ≤ 3.2 μm Ra | 60 bar |
| Dynamic reciprocating | 10–15% | 0.4–0.8 μm Ra | 30 bar |
| Dynamic rotary | 8–12% | 0.2–0.4 μm Ra | 10 bar |
Key note: VMQ silicone has significantly higher gas permeability than NBR, FKM, or Butyl. Do not specify VMQ for gas-tight sealing applications — use Butyl (IIR) or FKM for gas service O-rings.
Installation & Handling — VMQ-Specific Guidelines
Use silicone-compatible lubricant — apply silicone grease (e.g., Molykote 111, Dow Corning DC4) for installation; petroleum jelly or mineral oil degrades VMQ — never use petroleum-based lubricants on silicone O-rings
- Handle with clean hands or clean gloves — silicone surfaces are highly adhesive to dust and particulates; contaminated O-ring surfaces cause assembly difficulties and potential sealing defects
- Avoid sharp edges — VMQ has lower tear resistance than NBR; use installation sleeves and chamfered bore lead-ins to protect O-rings from sharp thread crests and bore edges during assembly
- Do not over-compress — VMQ has higher compression set than NBR at elevated temperature; stay within recommended 15–25% squeeze range for static applications
- Clean groove before installation — remove all old silicone residue (VMQ-to-VMQ adhesion can bond old and new material)
- Store away from solvent vapors — silicone absorbs some solvent vapors reversibly; sealed packaging storage is essential
Quality & Compliance
| Standard | Status |
|---|---|
| FDA 21 CFR 177.2600 | ✅ Compliant — standard grade red VMQ |
| EU (EC) 1935/2004 | ✅ Compliant — food contact |
| USP Class VI | ✅ Available on request |
| NSF/61 | ✅ Available on request |
| ISO 3601 dimensional | ✅ All metric sizes |
| AS568A dimensional | ✅ All imperial dash sizes |
| RoHS 2011/65/EU | ✅ Compliant |
| REACH 1907/2006 | ✅ Compliant |
| ISO 9001:2015 | ✅ Manufacturing QMS |
| EN 10204 Type 2.1 | ✅ Material cert on request |
FAQ
What is a red silicone O-ring assortment used for?
A red silicone O-ring assortment is used when multiple O-ring sizes are needed for industrial sealing, maintenance, repair or assembly. The O-rings are installed in grooves and compressed between mating surfaces to help reduce leakage in compatible equipment and fittings.
Why are silicone O-rings often supplied in red?
Red is commonly used as a visual identification color for silicone O-rings. It helps warehouse staff, assemblers and maintenance teams distinguish silicone seals from black NBR, EPDM or other rubber compounds, reducing the risk of material mix-up during installation.
Can the assortment size list be customized?
Yes. The assortment can be configured according to the buyer’s size list, standard references, equipment service kits or distributor requirements. Inner diameter, cross-section, quantity per size, packaging method and label format can be reviewed before production.
Are silicone O-rings suitable for oil or fuel service?
Silicone O-rings should be reviewed carefully when oil, fuel, solvent or aggressive chemical exposure is present. For petroleum oil or fuel applications, NBR, HNBR or FKM may be more suitable depending on the operating conditions. Material selection should be based on actual media contact.
Can FDA or RoHS documentation be provided?
FDA, RoHS, REACH and other documentation options are available upon request for applicable silicone compounds. Buyers should specify the required compliance standard, contact media, temperature range and end-use application before quotation and sample confirmation.
Are samples available before bulk assortment production?
Samples are available upon request. Sample planning depends on the O-ring sizes, silicone compound, hardness, tolerance, tooling status, packaging method and quantity. Please provide a size list, drawing or physical sample so the assortment can be reviewed accurately.
Request a Custom Quote
Send your red silicone O-ring assortment size list, standard reference, drawing or physical sample for technical review. Please include ID, cross-section, quantity per size, hardness, contact media, temperature range, pressure, packaging method and documentation requirements so we can prepare a practical quotation.
