.330 in Buna-N O-Ring Cord Stock 70A Durometer - 10 ft

In this review the reviewer examines the.330 in Buna-N O-ring cord stock to determine if it is a practical choice for common sealing and repair jobs. The bottom line: this 70A durometer, round cord is best for anyone needing a reliable, oil- and hydrocarbon-resistant rubber cord for DIY projects, plumbing seals, or small hydraulic repairs; the single biggest reason to buy is its balance of toughness and flexibility that makes creating custom O-rings or replacing small rubber tires straightforward and long lasting.

Key Features

• Material: Buna-N (Nitrile) construction offers resistance to petroleum and many hydraulic fluids, reducing swelling and failure in oil-exposed applications.
• Hardness: 70A durometer provides a firm but flexible seal that is easy to cut and glue while holding shape under compression.
• Temperature range: Usable across a wide temperature band suitable for many workshops and equipment, maintaining sealing performance in typical ambient and warm service conditions.
• Length and form: Supplied as a 10 ft piece of round cord stock, which is convenient for making multiple custom O-rings or continuous seals without repeated purchases.
• Made in USA: Domestic manufacture gives confidence in consistent material quality and dimensional accuracy.

Who It's For

This Buna-N O-ring cord stock is aimed at machinists, maintenance techs, and hobbyists who need a dependable rubber material that bonds well and resists oil, alcohols, and many aliphatic hydrocarbons. It is especially useful for users making replacement O-rings, small tire repairs, or custom seals where standard sizes are not available.

Those who should look elsewhere include users with heavy exposure to ozone, UV, or strong solvents such as acetone and esters, because Buna-N degrades in those environments. For extreme low temperature service well below -30 degrees F or high temperature continuous duty above 250 degrees F, a different elastomer would be more appropriate.

Pros & Cons

Pros

• Good resistance to petroleum and hydraulic fluids, making it suitable for many oil-exposed seals.
• 70A hardness balances rigidity and flexibility for easy cutting, gluing, and reliable sealing.
• Durable construction with reported longevity in customer use and useful for nonstandard repairs like small tires.

Cons

• Not resistant to ozone, sunlight, or solvents such as acetone and certain esters, limiting outdoor or chemical-exposed applications.

Specifications

Our Verdict

The.330 in Buna-N O-ring cord stock is a practical, good-value choice for workshop repairs and custom seals where oil resistance and reliable mechanical properties matter. It suits hobbyists and maintenance technicians who need an easy-to-use, durable rubber cord, provided the application avoids ozone, UV, and strong ketone or ester exposure.

Frequently Asked Questions

Can this cord be glued into O-rings?
Yes. Customers report it bonds easily with common rubber adhesives, making assembly of custom O-rings straightforward.

Is it safe for use with hydraulic fluids?
It is compatible with many petroleum-based and common hydraulic fluids, but check compatibility for specific fluids used in your system.

Can it be used outdoors?
Not recommended for prolonged outdoor exposure due to vulnerability to ozone, sunlight, and weathering; indoor and protected uses are best.