O-Rings and O-Ring Kits

AIMS Industrial stocks 24 O-ring kit, refill and splicing-kit lines from Champion, GJ Works and Loctite — NBR 70 (nitrile) and Viton 75 (FKM) compounds in metric and imperial sizes, from compact 110-piece kits up to 435-piece workshop assortments. If you need a single O-ring fast, or a kit that covers a whole range of common sizes for ongoing maintenance work, this is the range to start from.

O-Ring Kits at AIMS Industrial: NBR, Viton, Metric & Imperial

An O-ring kit is a compartmented case of pre-sorted O-rings covering a spread of common sizes, so a maintenance fitter or workshop always has a close match on hand instead of waiting on a single-size order. AIMS stocks assortment kits from 110 to 435 pieces, in NBR 70 (nitrile), Viton 75 (FKM), and a 90 Shore high-pressure compound, across metric and imperial sizing.

What's in an O-Ring Kit?

Each kit is a moulded organiser case with individual compartments, each holding one O-ring size (ID x cross-section). Piece counts across the AIMS range run from 110 pieces (Champion CA118 Viton kit) up to 435 pieces (GJ Works GKA435 imperial kit), with most kits sitting in the 380-420 piece range. A lid-mounted size chart or printed reference sheet is standard on these kits so you can identify a replacement without measuring every ring in the case.

O-Ring Material Quick Reference

*AIMS stocks NBR and Viton O-ring kits (see the range below). EPDM and silicone are included here for reference — useful when cross-checking a compound spec on equipment or an OEM part, or if you're sourcing those materials elsewhere. For the full chemical resistance chart across all four compounds, see the O-Ring Selection Guide.

The AIMS O-Ring Kit & Refill Range

• NBR 70 metric kits: Champion CA408 (408 pieces) and CA116 (130 pieces), GJ Works GKA380 (380 pieces) and GKA419 (419 pieces), plus metric refill packs for topping up an existing kit.
• NBR 70 imperial kits: Champion CA407 (407 pieces) and CA115 (115 pieces), GJ Works GKA420 (419 pieces) and GKA435 (435 pieces), plus imperial and Buna-N refill packs.
• Viton (FKM) kits: Champion CA118 assortment kit (110 pieces) and a Viton imperial refill pack, for higher temperatures and chemical resistance beyond what NBR handles.
• 90 Shore high-pressure kit: Champion CA212 (212 pieces) — harder-durometer O-rings for high-pressure hydraulic and pneumatic sealing.
• Air-conditioning & refrigerant kits: Champion CA411 (145 pieces) and matching refill, sized for automotive and industrial A/C and refrigerant fittings.
• Splicing kits: Loctite metric and imperial O-ring splicing kits, and Champion CA409 (imperial) and CA410 (metric) splicing assortment kits — O-ring cord plus splicing compound for joining a custom-length seal on-site when the exact moulded size isn't available.
• Individual O-rings by size: Champion COR nitrile O-rings sold individually in metric and imperial sizes, for a single one-off replacement without opening a full kit.

Sizing & Choosing the Right O-Ring

What is an O-ring?

An O-ring is a round-section elastomer ring that sits in a machined groove and seals between two mating surfaces under compression. The cross-section deforms to fill the groove and contact the sealing face on both sides, creating a leak-tight static or dynamic seal in hydraulic cylinders, pump shafts, pneumatic fittings, equipment housings and rotating or reciprocating shafts.

O-Ring Sizing — Measure Twice, Order Once

O-rings are specified by inside diameter (ID) x cross-section (CS) diameter. Measure both dimensions on the original seal with a caliper (cross-section) and a vernier or pin gauge (ID) — relying on housing dimensions alone can produce the wrong compression value and premature failure. Metric sizes use whole or half millimetres; imperial and many US-designed machines use the SAE AS568 dash-number series, where the dash number alone defines both ID and cross-section. If the original seal is damaged beyond measuring, send us the housing dimensions and we'll help identify the correct replacement.

Static vs Dynamic Seal Selection

Two sealing modes drive groove design and material choice:

• Static seals — between two non-moving surfaces (flange face, threaded plug, end cap). Groove finish and dimensioning are less critical, but compound choice still matters for media and temperature compatibility.
• Dynamic seals — on moving surfaces (rotating shaft, reciprocating piston rod, sliding fitting). These need a smoother sealing-face finish, correct groove dimensions, and a material that balances hardness against extrusion resistance. The wrong compound on a dynamic seal can fail within hours.

Companion Sealing Ranges at AIMS

• Oil Seals & O-Rings — our broader sealing range, covering rotary lip seals, V-rings and shaft seals for rotating machinery.
• Gaskets — PTFE, graphite, fibre and rubber sheet gaskets, plus spiral wound gaskets for flange applications. See the Spiral Wound Gasket Guide for ASME B16.20 colour codes and flange standards.
• Hose Clamps — for flexible-line connections that pair with O-ring fittings.
• Loctite — anaerobic flange sealants, RTV silicone gasket makers and pipe thread sealants. See the RTV Silicone Gasket Maker Guide and the broader Industrial Adhesive Types Guide.
• Pipe Flanges — for matching gasket and seal size to flange type.
• Hydraulics and Air Tools & Pneumatics — cylinders, valves and fittings that rely on O-ring sealing.

Order O-Ring Kits from AIMS Industrial

AIMS Industrial is a proudly Australian-owned industrial supplies business, and we work with trusted brands like Champion, GJ Works and Loctite to keep a genuinely useful O-ring range in stock. Can't identify your seal size or compound? Call (02) 9773 0122, contact our team or request a quote — send us the dimensions and we'll help identify the correct seal.

People Also Ask — O-Ring Kits and O-Rings

Q: What's in an O-ring kit, and what sizes do AIMS kits cover?

A compartmented case holding pre-sorted O-rings across a spread of common sizes, usually with a lid chart or reference sheet for identifying a match. AIMS stocks kits from 110 pieces up to 435 pieces, in NBR and Viton, metric and imperial, so most common repair sizes are covered from one kit.

Q: Which O-ring material should I use for my application?

Match the material to the fluid and temperature: NBR (nitrile) is the workshop default for oil, fuel, water and air up to around 120 degrees C. Viton (FKM) handles harsher chemicals, fuels and temperatures up to around 200 degrees C. EPDM suits steam, hot water and brake fluid but not petroleum oils. Silicone covers wide temperature ranges but has poor wear resistance, so it's used for static seals rather than moving parts. Always check chemical compatibility before committing to a material.

Q: When should I choose Viton over NBR?

Choose Viton when the seal will see fuel, solvents, aggressive chemicals, or sustained temperatures above what NBR is rated for (around 120 degrees C). NBR is the more cost-effective choice for mineral oil, water and air service within its temperature range — there's no need to pay for Viton's chemical resistance if the application doesn't call for it.

Q: What does the O-ring size code mean?

O-ring sizes are given as inside diameter (ID) x cross-section (CS) thickness. Metric sizes use whole or half millimetres; imperial sizes use fractional inches or the SAE AS568 dash-number series. Stocking a kit that covers common ID and cross-section combinations means most repairs can be matched without ordering a single size in.

Q: What is AS 568 dash number sizing?

SAE AS568 (formerly AS568A) is the American standard series that defines O-ring dimensions using a dash number: 001-050 covers small fractional-inch cross-sections, the 100 series is 1/16 inch cross-section, 200 series is 3/32 inch, 300 series is 1/8 inch, and 400 series is 3/16 inch. Once you know the dash number, ID and cross-section are both defined. It's commonly used alongside metric ISO sizing, particularly on imported machinery.

Q: Are O-ring kits worth buying vs individual sizes?

For maintenance and repair work, a kit is almost always better value — having a spread of sizes on hand for unplanned repairs typically pays for itself within a few jobs by avoiding a stop-work wait on a single seal. For high-volume production needing one consistent size at scale, buying that size in bulk is more cost-effective than a kit.

Q: What O-ring kit brands does AIMS stock?

Champion and GJ Works for NBR, Viton and high-pressure assortment kits and refills, and Loctite for O-ring splicing kits. All are available in metric and imperial sizing.

Q: Why does an O-ring fail prematurely?

Common failure modes: wrong material for the fluid (chemical attack and swelling), over-stretch on installation (permanent deformation), pinching during installation (a visible cut on the seal face), excessive heat (hardening and cracking), and extrusion through the gap when groove clearance is wrong. A kit with the correct ID and cross-section on hand avoids the stretch and pinch failures that come from forcing the wrong size into service.

Q: Should I use grease on O-rings during installation?

Yes — light lubrication helps the O-ring slide into position without rolling, twisting or scraping. Match the lubricant to the application fluid: silicone grease for water and steam, petroleum grease for oil and fuel systems. Avoid silicone grease on dynamic seals in oxygen service. A thin film is enough — excess lubricant doesn't improve the seal.

Q: What's the difference between static and dynamic O-ring grooves?

Static grooves (flange faces, threaded plugs, end caps) tolerate a rougher surface finish and simpler dimensioning. Dynamic grooves (rotating shafts, reciprocating pistons, sliding fittings) need a smoother sealing-face finish, precise groove geometry, and the right compression level — getting this wrong on a dynamic seal causes rapid extrusion or spiral failure, often within hours.

Q: What causes compression set failure in O-rings?

Compression set is the permanent deformation of an O-ring after prolonged compression — it loses its round cross-section, takes on a flat-oval shape, and eventually leaks. Causes include excessive temperature for the material grade, inadequate compression (too little pinch), or over-compression (too much groove fill). Picking the right material for the temperature and re-inspecting long-service seals at scheduled maintenance both help avoid it.

Q: How long can O-rings be stored before use?

Storage life depends on the elastomer. NBR has a nominal shelf life of around 5-7 years stored below 25 degrees C, away from direct sunlight and ozone sources such as electric motors or welding equipment. Viton lasts longer again — commonly 10+ years — under the same conditions. Once installed under compression, service life differs from storage life. Rotate stock oldest-first and inspect for surface cracking or hardening before installation.

Q: When should I use a dowty washer instead of an O-ring?

Dowty washers (bonded seals) combine a metal washer with a bonded rubber inner seal, used where a threaded joint needs sealing against pressure without a machined O-ring groove — common on BSP threaded ports on hydraulic cylinders, valves and manifolds. O-rings need a groove; dowty washers only need a flat mating face. See our Dowty Washer Guide for sizing.

Q: What's in an O-ring splicing kit, and when would I use one?

A splicing kit pairs O-ring cord with a splicing compound so you can cut a length to size and join it into a ring on-site — used for large-bore or non-standard sizes that aren't available as a moulded ring. AIMS stocks metric and imperial splicing kits from Loctite and Champion.

Q: Why shouldn't imperial and metric NBR O-rings be assumed interchangeable by eye?

Metric and imperial sizes can look very similar side by side, so cross-section and ID should always be confirmed in millimetres (or converted consistently) before ordering — a near-enough match can still be loose enough to leak or tight enough to over-compress.