O-Ring Bounce Testers Explained: How the Canyon O-Ring Identifier (COI) Helps You Identify Elastomer Materials

In the field or on the shop floor, identifying an O-ring's material can be a major challenge. Labels wear off, documentation gets lost, and you’re left wondering: is this EPDM, Nitrile, Perfluoroelastomer, or Viton? Choosing the wrong material can lead to catastrophic seal failure; but replacing every unidentified O-ring with an expensive universal material like FFKM isn’t a cost-effective solution either.

That’s where the O-ring bounce tester comes in.

Also known as an ORID (O-Ring Identification Device), this compact, mechanical tool lets you perform a simple, fast material identification test in seconds. At Canyon Components, we offer our own improved version: the Canyon O-Ring Identifier (COI).

In this guide, we’ll explain what bounce testing is, how the COI tool works, its benefits, limitations, and how it compares to other testing methods.

What Is an O-Ring Bounce Tester?

An O-ring bounce tester is a handheld tool that helps identify an elastomer material by observing how a precisely dropped weight bounces when impacting a standardized O-ring. The bounce behavior is determined by the material’s hardness, rebound characteristics, and internal damping; all of which vary by compound type.

The Canyon O-Ring Identifier (COI) builds on this concept, offering a compact, user-friendly design with material-specific comparison charts for quick reference. The COI is designed for repeatable use, helping engineers, technicians, and quality teams quickly narrow down material types without lab analysis.

How the Canyon O-Ring Identifier Works

The COI includes:

• A precision vertical guide tube
• A calibrated drop height
• A standardized, chisel tipped weight for consistent bounce behavior
• A quick-reference label common materials and typical bounce heights

The entire tool is housed in a small form factor durable case for portability and long-lasting use.

To use the tool:

1. Place the O-ring in question on a solid, flat surface. To avoid inaccurate results, the surface should be rigid and dense.
2. Hold the Canyon O-ring Identifier (COI) in a vertical position, with the Chisel Tip of the brass weight hanging freely.
3. Center the Chisel Tip on the O-ring's cross section and allow the end of the stainless steel tube housing to make full contact with the O-ring. At this point, the Peg should be aligned with the FKM (Viton™) indicator line on the label.
4. Raise the weight as high as possible while keeping the bottom end of the steel tube in full contact with the O-ring.
5. Release the weight and allow it to drop unimpeded into the O-ring. The weight will bounce and on the first bounce, the Peg will align with one of the four calibrated material ranges: FKM (Fluoroelastomer, Viton™), Perfluoroelastomer (FFKM, Kalrez®, Canrez®, Chemraz®), Buna N (NBR, Nitrile), or EPDM.

Bounce height typically correlates with an O-ring's elasticity and hardness, which vary by compound. The higher the rebound, the more elastic and less dampened the material.

Benefits of the Bounce Tester Approach

Bounce testing provides a range of advantages, particularly for field teams and MRO departments:

• Non-destructive: Test the O-ring without cutting, stretching, or damaging it
• Fast: Identify materials in seconds with no waiting on lab results
• Portable: The COI fits into a tool bag or drawer and can be used anywhere
• No electricity or software needed: Works in field environments without tools or power
• Cost-effective: Avoid unnecessary replacements or over-specifying parts
• Improves inventory control: Match incoming or legacy parts without relying on labels

Use Cases:

• Before installing an O-ring
• Verification of known materials
• Checking for labeling issues
• Incoming quality inspection
• Maintenance troubleshooting
• Sorting and stockroom inventory identification
• Customer service and sample evaluation
• Jobsite identification when documentation is missing

For maintenance teams and engineers working with a wide range of elastomers, the COI saves time, prevents errors, and reduces waste. It enables a first-pass material guess that can either verify assumptions or point to the need for further lab testing.

Limitations of Bounce Testing

While extremely useful, bounce testers are not infallible. Consider the following limitations:

• Testing surface matters: The table or surface that the O-ring is sitting on during a bounce test can have an effect on the perceived results of the test. For example, a thin metal table might be "springier" than a granite slab. The spring of the metal table can cause the weight of the COI to bounce higher, potentially giving the user errored results. Ideally, the testing surface is solid and neutral, like a thick slab of metal, rock, or wood.
• Materials not included on the label scale: The COI includes four materials on it's built-in scale: EPDM, Buna-N, Perfluoroelastomer, and FKM. Materials not included within this group should not be tested with this tool.
• Geometry matters: The COI bounce tester is specifically calibrated for O-rings within the cross sectional range of 0.103" to 0.275" (2.62mm to 6.99mm). Testing any other geometry could result in inaccurate readings from the tool.
• Hardness matters: The COI bounce tester is specifically calibrated for 70 shore A O-rings. Testing any other hardness could result in inaccurate readings from the tool (however, the tool can still be relatively accurate for 75 shore A materials).
• Not for precise material certification: The COI identifies general material families, not exact compounds or formulations
• O-ring condition matters: Aged, swollen, or damaged O-rings may not bounce consistently
• Temperature sensitivity: Cold or hot O-rings may behave differently than those at room temperature
• Operator variability: Visual estimation of bounce height may vary slightly from person to person

For high-accuracy identification or critical applications, Canyon Components offers lab-based methods like FTIR (Fourier Transform Infrared Spectroscopy), thermogravimetric analysis (TGA), and hardness testing.

When to Use the COI vs. Lab Testing

Scenario	Recommended Method
Field maintenance check	COI bounce tester
Verifying new shipment	COI for screening, lab for confirmation
Identifying legacy or unknown seals	COI first, lab if uncertain
Regulatory or customer specification compliance	Lab testing only
Material requalification or dispute resolution	Lab testing only

Lab analysis is still the gold standard when traceability, certification, or performance-critical applications are involved. But in most general-purpose O-ring identification situations, the COI provides quick and useful results.

How to Use the COI in Your Workflow

Here are common use cases where the COI fits perfectly into your inspection and maintenance routines:

• MRO Inventory Reorganization: Have a drawer full of unlabeled O-rings? Use the COI to sort them into material groups.
• On-Site Equipment Repairs: Avoid delays or guesswork when replacing old or degraded O-rings. Test the original and match accordingly.
• Receiving Inspection: Screen incoming shipments of unidentified or incorrectly labeled parts before they hit production.
• Sales and Distribution: Distributors can use the COI to respond to urgent customer requests for cross-matching unknown parts.
• Quality Control: Keep a COI at the QC bench to double-check material claims before putting seals into service.

Where to Get the Canyon O-Ring Identifier

The COI is available directly from Canyon Components. It can be purchased individually or included as part of a field sealing kit. Bulk pricing is available for MRO departments and OEMs.

To request a quote or place an order, contact Canyon Components or speak with our sales team.

Related Products and Services

If you're identifying O-rings, you may also be interested in:

• Material testing services: FTIR, TGA, durometer analysis, density tests
• O-ring measurement tools: Cones, tapes, sizing guides
• Custom seal kitting: Organized kits of O-rings by material and size
• Cross-reference support: Identify parts based on OEM part numbers or competitor SKUs
• Reverse engineering services: When you need a replacement but only have the sample

Conclusion

In a world where material mix-ups can lead to costly downtime or safety issues, having a quick way to identify O-ring compounds is invaluable. The Canyon O-Ring Identifier (COI) bounce tester gives you that capability, in seconds, without damage, and without guesswork.

Whether you're replacing a worn seal, checking incoming inventory, or matching a customer sample, the COI puts material knowledge in the palm of your hand. Add it to your toolkit today and take the mystery out of material identification.