.375 in Silicone O-Ring Cord Stock 70A Durometer - Red

In this review the reviewer examines the.375 in silicone O-ring cord stock to determine whether it suits workshop and industrial sealing tasks. The bottom line is that this red, round-section silicone cord with a 70A durometer is best for users who need a chemically tolerant, high-temperature sealing material that is easy to cut and form into custom O-rings or gaskets. The review focuses on practical performance: temperature tolerance, chemical compatibility, and usability for repairs and prototyping where a consistent thickness and reliable resilience matter.

Key Features

• Material: Silicone construction provides broad resistance to ozone, weathering, detergents and many oils, making it suitable for outdoor and marine exposures.
• Temperature range: Rated for extreme temperatures, this cord handles very low and very high temperatures for most automotive, HVAC and industrial applications.
• Durometer: The 70A hardness offers a balance of flexibility and firmness that works well for general-purpose seals and reusable gaskets.
• Form factor: The round cross-section and consistent 0.375 in thickness make it straightforward to cut, size and form into replacement O-rings or custom seals.
• Origin: Made in the U. S. A., which can be important for quality control and lead time expectations in professional settings.
• Length options: Supplied as a 25 ft piece, it provides enough material for multiple repairs and prototypes without frequent restocking.

Who It's For

This cord is aimed at maintenance technicians, hobbyists and small shops that need a reliable silicone option for custom seals, emergency repairs or prototype builds. The chemistry resistance and extended temperature capability make it a practical choice for equipment exposed to weather, detergents, salt water and many hydraulic or non-petroleum fluids.

It is less suited for applications that involve prolonged contact with steam above 250 degrees F, aromatic hydrocarbons, strong acids or fuels where silicone is known to be vulnerable. Users who require a softer or much harder durometer should look to alternative materials or durometers.

Pros & Cons

Pros

• Good chemical resistance and weatherability for outdoor and marine use.
• Wide usable temperature range that suits many automotive and industrial tasks.
• 70A durometer gives a practical balance of resilience and sealability for general repairs.
• Long 25 ft length provides material for multiple uses and reduces frequent repurchasing.

Cons

• Silicone is vulnerable to certain solvents, aromatic hydrocarbons and prolonged high-temperature steam, so it is not universal for every fluid environment.

Specifications

Our Verdict

The.375 in silicone O-ring cord stock is a strong value for anyone needing a durable, chemically tolerant cord for custom seals and repairs. Its 70A hardness and broad temperature tolerance make it versatile for many maintenance and prototyping tasks, while the 25 ft length keeps costs reasonable for shops and hobbyists. Avoid it where exposure to aromatic solvents, high-pressure fuel contact or extended steam above 250 degrees F is expected.

Frequently Asked Questions

Can this cord be used to make replacement O-rings?
Yes. The round cross-section and consistent 0.375 in diameter make it suitable for cutting and forming into custom O-rings and gasket loops.

What fluids is silicone resistant to?
Silicone resists ozone, weather, detergents, salt water, engine and transmission oil, non-petroleum brake fluid and many fire-resistant hydraulic fluids, as well as vegetable and animal oils.

Where should this cord not be used?
Avoid prolonged exposure to steam above 250 degrees F, aromatic hydrocarbons like benzene, certain chlorinated solvents, strong acids and bases, and hydrocarbon fuels where silicone is vulnerable.