Cord Stock
Cord Stock
Cord Stock is an extruded elastomer sealing material used to manufacture custom O-rings, large-diameter seals, and special-profile sealing solutions. When standard AS568 or metric O-rings cannot meet dimensional requirements, cord stock provides a cost-effective and flexible alternative. It is widely used in industrial equipment, maintenance repairs, large flanges, doors, tanks, and static sealing applications where custom sizes are required.
Why Choose Cord Stock?
Custom sealing applications often require dimensions that are unavailable in standard O-ring catalogs. Cord stock allows engineers and maintenance teams to create seals that fit the exact application.
Manufacture Custom-Sized O-Rings
Cord stock can be cut to the required length and vulcanized into virtually any inside diameter, making it ideal for oversized or non-standard sealing applications.
Reduce Inventory Costs
Instead of stocking hundreds of different O-ring sizes, maintenance departments can keep a small selection of cord diameters and fabricate seals as needed, improving inventory efficiency.
Fast Solution for Equipment Maintenance
When replacement seals are unavailable or discontinued, cord stock enables rapid on-site fabrication, minimizing equipment downtime.
Suitable for Multiple Seal Profiles
In addition to standard round cord, manufacturers also supply square, X-ring, rectangular, and backup ring profiles to meet different sealing requirements.
Available Materials
Selecting the proper compound is critical for sealing performance and service life.
| Material | Key Advantages | Typical Applications |
|---|---|---|
| NBR (Buna-N) | Excellent oil resistance and abrasion resistance | Hydraulic equipment, general industrial sealing |
| FKM (Viton®) | High temperature and chemical resistance | Chemical processing, automotive, oil & gas |
| EPDM | Superior water, steam, and weather resistance | Water systems, outdoor equipment |
| Silicone (VMQ) | Wide operating temperature range | Food equipment, medical devices |
| HNBR | Excellent wear and heat resistance | Heavy-duty hydraulic systems |
| Fluorosilicone (FVMQ) | Fuel and chemical compatibility | Aerospace and fuel system sealing |
Common Cord Stock Profiles
Different cross-sections are designed for specific sealing applications.
- Round Cord – Used to manufacture custom O-rings for static sealing.
- Square Cord – Provides greater sealing contact area and improved stability.
- X-Ring Cord – Four-lobed profile that reduces friction while improving sealing efficiency.
- Rectangular Cord – Suitable for special gland geometries.
- Backup Ring Cord – Designed for high-pressure sealing systems to support O-rings and prevent extrusion.
How to Select the Right Cord Stock
Choose the Correct Material
Consider compatibility with:
- Hydraulic oil
- Fuel
- Water
- Steam
- Cleaning chemicals
- UV and ozone exposure
Incorrect material selection is one of the most common causes of premature seal failure.
Select the Proper Cross-Section
The cord diameter should match the groove design and required compression. Oversized or undersized cord may lead to leakage or excessive compression set.
Determine the Manufacturing Method
For permanent sealing applications, vulcanized joints provide stronger and more reliable performance than adhesive-bonded joints, especially in larger diameter O-rings.
Verify Dimensional Tolerances
For precision equipment, choose cord stock manufactured to recognized tolerance standards to ensure consistent compression and sealing performance.
Common Problems Cord Stock Solves
Properly selected Cord Stock helps solve:
- Non-standard O-ring size requirements
- Large-diameter sealing applications
- Obsolete or discontinued seal replacements
- Emergency maintenance repairs
- Long lead times for custom molded O-rings
- Excessive inventory of standard seal sizes
For many maintenance departments and OEM manufacturers, cord stock offers a practical way to shorten delivery times while maintaining sealing reliability.
Build Custom Sealing Solutions with High-Quality Cord Stock
Cord Stock offers engineers and maintenance professionals the flexibility to create custom seals without the limitations of standard O-ring sizes. Whether producing oversized O-rings, replacing obsolete seals, or supporting rapid equipment repairs, selecting the correct material, profile, and manufacturing method ensures dependable long-term sealing performance across a wide range of industrial applications.
| Compounds | Durometer | Material | Description | Color | Temp Range (F) |
|---|---|---|---|---|---|
| A75-G101 | 78 | AFLAS | General purpose | Black | +14 to +400 |
| A90-G101 | 90 | AFLAS | General purpose | Black | +14 to +400 |
| C70-D101 | 70 | Neoprene | Environmental resistance | Black | -40 to +212 |
| E70-D101 | 70 | EPDM | General purpose | Black | -67 to +257 |
| E70-E501 | 70 | EPDM | FDA-Grade | White | -40 to +250 |
| F70-E401 | 70 | Fluorosilicone | Mil-R-25988B Class 1 Grade 70 Type 2 | Blue | -76 to +350 |
| H80-E101 | 80 | HNBR | Heat/Chemical resistance | Black | -40 to +320 |
| H90-S101 | 90 | HNBR | Heat/Chemical resistance | Black | -40 to +320 |
| N50-E101 | 50 | NBR | General purpose | Black | -40 to +212 |
| N70-D101 | 70 | NBR | General purpose | Black | -40 to +212 |
| N70-E501 | 70 | NBR | FDA-Grade | White | -40 to +212 |
| N90-E101 | 90 | NBR | General purpose | Black | -40 to +212 |
| S50-E601 | 50 | Silicone | FDA Compliant, ZZ-R-765 Class 2A & 2B Grade 50 | Red | -65 to +425 |
| S70-D601 | 70 | Silicone | FDA-Grade | Red | -76 to +437 |
| V75-G101 | 75 | FKM | Viton GFLTS | Black | -40 to +400 |
| V75-G103 | 75 | FKM | General purpose Genuine Viton | Black | -25 to +400 |
| V75-G201 | 75 | FKM | General purpose Genuine Viton | Brown | +1 to +400 |
| V75-G501 | 75 | FKM | FDA-Grade Genuine Viton | White | -2 to +400 |
| V90-G101 | 90 | FKM | General purpose Genuine Viton | Black | -25 to +400 |
Rope dimensions and tolerances
| Inch | MM | Common Name | Tolerance | LOW | High |
|---|---|---|---|---|---|
| .039 | 1 | 1 MM | +/- .010 | 0.029 | 0.049 |
| .063 | 1.6 | 1/16” Actual | +/- .014 | 0.049 | 0.077 |
| .070 | 1.8 | 1/16” Nominal | +/- .014 | 0.056 | 0.084 |
| .079 | 2 | 2 MM | +/- .014 | 0.065 | 0.093 |
| .093 | 2.4 | 3/32” Actual | +/- .014 | 0.079 | 0.107 |
| .103 | 2.6 | 3/32” Nominal | +/- .016 | 0.087 | 0.119 |
| .118 | 3 | 3 MM | +/- .016 | 0.102 | 0.134 |
| .125 | 3.2 | 1/8” Actual | +/- .016 | 0.109 | 0.141 |
| .139 | 3.5 | 1/8” Nominal | +/- .016 | 0.123 | 0.155 |
| .157 | 4 | 4 MM | +/- .016 | 0.141 | 0.173 |
| .177 | 4.5 | 4.5 MM | +/- .020 | 0.157 | 0.197 |
| .188 | 4.8 | 3/16” Actual | +/- .020 | 0.168 | 0.208 |
| .196 | 5 | 5 MM | +/- .020 | 0.176 | 0.216 |
| .210 | 5.3 | 3/16” Nominal | +/- .020 | 0.19 | 0.23 |
| .218 | 5.5 | 7/32” | +/- .020 | 0.198 | 0.238 |
| .224 | 5.7 | 5.7 MM | +/- .020 | 0.204 | 0.244 |
| .236 | 6 | 6 MM | +/- .020 | 0.216 | 0.256 |
| .250 | 6.4 | 1/4” Actual | +/- .027 | 0.223 | 0.277 |
| .275 | 7 | 1/4” Nominal, 7MM | +/- .027 | 0.248 | 0.302 |
| .295 | 7.5 | 7.5 MM | +/- .027 | 0.268 | 0.322 |
| .313 | 8 | 5/16” | +/- .027 | 0.286 | 0.34 |
| .330 | 8.4 | 8.4 MM | +/- .027 | 0.303 | 0.357 |
| .354 | 9 | 9 MM | +/- .027 | 0.327 | 0.381 |
| .375 | 9.5 | 3/8” | +/- .027 | 0.348 | 0.402 |
| .393 | 10 | 10 MM | +/- .031 | 0.362 | 0.424 |
| .437 | 11.1 | 7/16” | +/- .031 | 0.406 | 0.468 |
| .472 | 12 | 12 MM | +/- .031 | 0.441 | 0.503 |
| .500 | 12.7 | 1/2” | +/- .031 | 0.469 | 0.531 |
| .550 | 14 | 14 MM | +/- .031 | 0.519 | 0.581 |
| .562 | 14.3 | 9/16” | +/- .031 | 0.531 | 0.593 |
| .590 | 15 | 15 MM | +/- .031 | 0.559 | 0.621 |
| .625 | 15.9 | 5/8” | +/- .031 | 0.594 | 0.656 |
| .688 | 17.5 | 11/16” | +/- .039 | 0.649 | 0.727 |
| .750 | 19.1 | 3/4” | +/- .039 | 0.711 | 0.789 |
| .813 | 20.7 | 13/16” | +/- .039 | 0.774 | 0.852 |
| .875 | 22.2 | 7/8” | +/- .039 | 0.836 | 0.914 |
| 1.000 | 25.4 | 1” | +/- .051 | 0.949 | 1.051 |
| 1.125 | 28.6 | 1-1/8” | +/- .051 | 1.074 | 1.176 |
| 1.250 | 31.8 | 1-1/4” | +/- .051 | 1.199 | 1.301 |
| 1.375 | 34.9 | 1-3/8” | +/- .051 | 1.324 | 1.426 |
| 1.500 | 38.1 | 1-1/2” | +/- .051 | 1.449 | 1.551 |