.139ft (1/8 in) Buna-N O-Ring Cord Stock 70A - 100 ft Spool

In this review the reviewer finds the.139' Buna-N O-Ring Cord Stock to be a practical choice for anyone needing a durable, glueable round cord for custom O-rings and repairs. The biggest reason to buy is its balance of durability and chemical compatibility: the Buna-N material resists petroleum fluids and many hydraulic fluids while offering a useful temperature range, making it a versatile workshop staple rather than a precision sealing solution for extreme environments.

Key Features

• Material: Buna-N (Nitrile) provides good resistance to petroleum, HFA, HFB and HFC fluids so it works well in many hydraulic and pneumatic repair tasks.
• Hardness: The 70A durometer gives a firm, resilient seal that holds shape for custom O-rings and gasket repairs while remaining easy to cut and glue.
• Temperature range: Rated for a wide working range so it performs from cold starts to reasonably hot applications without immediate degradation.
• Length and format: Supplied on a 100 ft spool, it is convenient for frequent small repairs and for producing many replacement rings without repeated ordering.
• Made in the U S A: Domestic manufacture offers predictable material quality and consistent cross section for repeatable fittings.

Who It's For

This cord stock is best for maintenance technicians, hobbyists, and small shops that need to form custom O-rings, replace rubber tires on small wheels, or create seals for general hydraulics and plumbing tasks. Its combination of durability and compatibility with petroleum and many hydraulic fluids makes it suitable for everyday workshop use.

It is not the ideal choice for applications exposed to ozone, sunlight, or high UV environments, nor for systems requiring chemical resistance to acetone, ethers, or esters. For those situations a different elastomer should be considered.

Pros & Cons

Pros

• Good chemical compatibility with petroleum and various hydraulic fluids, making it reliable for many sealing tasks.
• 70A durometer offers a balance of firmness and flexibility for easy gluing and lasting shape.
• 100 ft spool provides strong value for repeated repairs and custom ring production.
• Customers report good fit, adhesive ease, and durability in common uses like replacement tires.

Cons

• Not resistant to ozone, UV, or certain solvents such as acetone and esters, so it can fail in outdoor or solvent-exposed applications.
• Size and leak resistance received mixed comments from some users, indicating verification is recommended for critical seals.

Specifications

Our Verdict

The.139' Buna-N O-Ring Cord Stock is a solid, cost-effective choice for general maintenance, hydraulic shop repairs, and hobby projects where resistance to petroleum and common hydraulic fluids matters. Buyers seeking a durable, easy-to-glue cord on a large spool will find it good value, but those needing ozone or UV resistance should select a different compound.

Frequently Asked Questions

Can this cord be glued into rings?
Yes, customers note it bonds easily with common rubber adhesives designed for nitrile compounds.

Is it suitable for outdoor use?
No, Buna-N is vulnerable to ozone and UV, so outdoor or weather-exposed installations are not recommended.

What fluids is it compatible with?
Compatible with petroleum, HFA, HFB, HFC fluids, vegetable oil, alcohol and some acids; avoid acetone, ethers and esters.