.472 in (12 mm) Buna-N O-Ring Cord Stock 70A - 10 ft Piece

In this review the reviewer finds the.472 in (12 mm) Buna-N O-Ring Cord Stock best suited for workshop repairs and custom sealing jobs where a durable, fuel-resistant rubber cord is needed. The bottom line: this 70A durometer, round cord delivers a dependable balance of firmness and flexibility for many hydraulic, pneumatic, and general industrial applications, and its US-made construction is the single biggest reason to consider it for parts that see petroleum or vegetable-oil exposure.

Key Features

• Material: Buna-N (Nitrile, NBR) offers broad compatibility with petroleum-based fluids and many industrial oils.
• Hardness: The 70A durometer provides a firm sealing surface that resists compression set while still allowing for reliable gland seating.
• Temperature range: Rated for wide use, it tolerates typical service temperatures encountered in workshops and equipment from sub-freezing to high heat.
• Length and size: Supplied as a 10 ft piece of.472 in (12 mm) round cord, it is long enough for multiple custom o-rings or repairs from a single cut.
• Durability: Buna-N construction brings good abrasion and tear resistance, useful for parts exposed to repeated motion or mechanical wear.
• Origin: Made in the U.S.A., which helps ensure consistent material quality and batch traceability.

Who It's For

This cord is aimed at home mechanics, maintenance techs, and hobbyists who need a practical material for replacing or fabricating o-rings, small seals, or even rubber tire edges where petroleum compatibility and durability matter. It is particularly useful when working with hydraulic fittings, fuel system components, or pumps that use HFA/HFB/HFC fluids.

Those who should look elsewhere include users requiring ozone or UV resistance, or applications exposed to solvents such as acetone, ethers, or esters; Buna-N degrades under those conditions, and a specialty compound such as EPDM or silicone would be a better fit.

Pros & Cons

Pros

• Good chemical compatibility with petroleum, vegetable oils, and many hydraulic fluids for reliable sealing.
• 70A durometer balances firmness and flexibility for easy gluing and stable o-ring formation.
• Long 10 ft length and standard cross section let users make multiple seals or repairs from one piece.
• Solid build quality and abrasion resistance noted by customers who reported durable, long-lived parts.

Cons

• Not suitable for environments with ozone, strong solvents, or prolonged UV exposure, where the material will deteriorate.
• Size and leak resistance received mixed feedback for specialized sealing tolerances, so precision applications may require testing.

Specifications

Material	Buna-N (Nitrile, NBR)
Cross Section	Round cord,.472 in (12 mm)
Durometer	70A
Length	10 ft piece
Temperature Range	-40 degrees F (-40 degrees C) to 212 degrees F (100 degrees C)
Chemical Compatibility	Petroleum, HFA/HFB/HFC fluids, vegetable oil, alcohols, acids, aliphatic hydrocarbons
Origin	Made in the U.S.A.

Our Verdict

For most maintenance and DIY sealing tasks this.472 in Buna-N cord is a practical, cost-effective choice thanks to its chemical resistance, firm 70A hardness, and 10 ft length that yields multiple seals. It is good value for users working with fuels and oils, but avoid it in ozone- or UV-exposed installations where alternative materials are required.

Frequently Asked Questions

Can this cord be glued to make custom o-rings?
Yes, customers report it is easy to glue into o-rings using standard rubber adhesives suitable for nitrile.

Is it safe for fuel system seals?
It is compatible with petroleum and many aliphatic hydrocarbons, making it suitable for many fuel-related seals, but test in your specific application before final use.

What should be avoided?
Avoid exposure to acetone, ethers, esters, ozone, and prolonged sunlight or weathering, as Buna-N will degrade under those conditions.