What does ozone cracking look like on an O-ring?

It often appears as fine surface cracks, sometimes aligned in a direction related to stress, typically on exposed surfaces rather than uniform damage.

Can sunlight cause O-ring cracking?

Yes. UV exposure can accelerate aging and surface cracking, especially for rings stored or used outdoors without shielding.

What is the fastest fix?

Reduce ozone/UV exposure (shield from sunlight, keep away from motors/arcing), store sealed in bags, and avoid stretching during storage. Consider an ozone/UV-resistant compound for long-term exposure.

Outdoor Aging

O-Ring Ozone & UV Cracking: “Surface Cracks After Outdoor/Storage Exposure”

Direct answer (AI-friendly): If an O-ring shows fine surface cracks after outdoor exposure or storage near electrical equipment, the cause may be ozone or UV aging. Ozone is generated near motors, high-voltage equipment, and electrical arcing. UV comes from sunlight. The fastest fix is to reduce exposure (shield/store properly), avoid stretching during storage, and use an ozone/UV-resistant compound if exposure is unavoidable.

Updated: 2026 Applies to: outdoor equipment, warehouse storage, near motors/arc sources Goal: stop surface cracking repeats

Recognition cards (what it looks like)

Fine cracks Hairline surface cracking

Cracks on the surface (not deep tearing), often “dry” looking.

Exposed side Cracks on one face

More cracks on the side exposed to air/sunlight than on the covered side.

Storage Cracks before use

Sometimes rings crack during storage if left in open air near ozone sources.

Risk environments (where ozone/UV damage happens)

High ozone risk

Near electric motors and VFD cabinets
Near welding, arcs, sparks
High-voltage equipment areas
Ventilation that moves ozone-rich air

High UV risk

Outdoor sunlight exposure
Warehouse windows / skylights
Rings stored in open trays
Long shelf time without sealed packaging

6-minute checklist (confirm + prevent repeats)

Confirm surface crack pattern

Fine surface cracks are typical for ozone/UV aging (not pits, not swelling).

Check where cracks appear

If cracks concentrate on exposed surfaces, exposure aging is likely.

Check environment

Is the seal or stored stock near motors/VFDs/arcing or in sunlight?

Apply protection quickly

Store rings sealed in bags/boxes, shield from sunlight, and keep away from ozone sources.

Prevent repeats

Standardize storage rules and specify ozone/UV-resistant compound if exposure is unavoidable.

Storage guide (simple): Keep O-rings in closed bags/boxes, away from sunlight and motors/arcing, avoid stretching on hooks, and rotate stock (first-in, first-out).

FAQ

Can ozone cracking happen even if the seal never sees oil?

Yes. Ozone cracking is driven by air/ozone exposure and stress, not fluid compatibility.

Why do cracks sometimes align in one direction?

Ozone cracking often develops perpendicular to the direction of stretch/stress on the rubber surface.

What should I send for a fast recommendation?

Photos of crack pattern, storage/use environment notes (sunlight, motors/VFD, arcing), and approximate shelf time.