You've probably asked yourself this while choosing tubing or filter bowls: is nylon stronger than plastic?

As a quality inspector at Festo, I review hundreds of material certifications each year—roughly 200, maybe 180 if I'm being precise (I'd have to check our Q4 data). And I can tell you the question itself is where most people trip up. Nylon is a plastic. The real question is whether nylon is stronger than specific plastics like polypropylene, polycarbonate, or polyurethane, and that depends entirely on the property you're comparing.

This checklist is for engineers, maintenance managers, and buyers who need to specify or verify plastic components in pneumatic systems—tubing, filter bowls, plastic rods, and fittings. It'll help you avoid the material mix-ups I see on a weekly basis.

Here are the seven steps I use when qualifying materials.

The 7-Step Material Qualification Checklist

Step 1: Name the exact polymer family

Stop saying 'plastic.' Say 'PA12 nylon,' 'polypropylene homopolymer,' or 'thermoplastic polyurethane.' They're completely different materials, and their mechanical properties reflect it.

  • Nylon (PA6, PA12): high tensile strength, good abrasion resistance, but absorbs moisture.
  • Polypropylene (PP): lightweight, excellent chemical resistance, lower strength.
  • Polyurethane (PU): outstanding flexibility and abrasion resistance—common for tubing that bends a lot.
  • Polycarbonate (PC): strong and transparent—the usual choice for FRL filter bowls.

Checkpoint: if the spec sheet doesn't name the resin family, stop and ask why.

Step 2: Define what 'strong' means in your application

People think 'is nylon stronger than plastic?' is a simple yes/no. Actually, it's an incomplete comparison. Nylon has higher tensile strength than polypropylene (typically 40–50 MPa vs. 25–35 MPa, per ISO 527), but polyurethane often beats nylon in abrasion resistance, and polycarbonate is tougher when it comes to impact.

The assumption is that a material's strength is inherent to its name. The reality is that 'nylon' and 'polypropylene' describe families of materials, not fixed property sets. The material's formulation and processing determine performance.

So before comparing numbers, ask: what failure mode am I trying to prevent? If your tubing has to survive constant flexing, tensile strength won't be your deciding factor.

I went back and forth between nylon and polyurethane for a robot arm application once. Nylon offered a better pressure rating; polyurethane offered tighter bend radii. We went with polyurethane, and it saved us from recurring fatigue failures.

Step 3: Verify the actual material properties

Once you know what to measure, pull the datasheet values. I always check tensile strength, Shore hardness (ISO 868), and abrasion resistance.

Don't rely on a supplier's word. In 2024, we rejected 8,000 polypropylene rods because the durometer read 63D against a 68D spec. Normal tolerance is ±2D. The vendor called it 'within industry standard.' We rejected it anyway, and they redid it at their cost. Now every contract includes Shore hardness requirements.

A quick pointer: when comparing tensile values, make sure both datasheets use the same test standard (ISO 527 for plastics). Otherwise, you're not comparing apples to apples.

Step 4: Check environmental compatibility

A material that performs well in a lab test can fail in your plant. Three things I always check:

  • Moisture: nylon absorbs moisture, which reduces dimensional stability and mechanical strength over time. If your environment is humid, factor this in.
  • Oil and chemicals: polypropylene has limited resistance to hydrocarbons; nylon and polyurethane are generally better.
  • UV exposure: some plastics get brittle with prolonged sun exposure. Look for UV-stabilized grades if the application is outdoors.

This step is easy to skip, but I've seen plastic bowls on FRL units turn brittle and crack from UV degradation after a year outside.

Step 5: Measure dimensions and tolerances

Now open the micrometer and check physical specs. For tubing, measure outer diameter and wall thickness at several points along the length—not just once. Wall thickness variation is a common defect.

For plastic bowls on filter regulators, check wall thickness consistency and transparency. A bowl that looks streaky or frosted at 2mm thickness usually signals poor processing.

For polypropylene plastic rod, check diameter tolerance and straightness. Bowed rod stock creates all kinds of downstream problems.

Checkpoint: if measurements fall outside the datasheet tolerance, reject the batch before it hits inventory.

Step 6: Verify documentation and traceability

Material certifications are not optional paperwork. They tie a physical batch of material back to the manufacturer's stated properties.

When we buy components, we request the raw material certificate and compare it against the product datasheet. For Festo products, the most reliable path is to log in to the Festo support portal—your festo login gives you access to official datasheets and test reports.

If you can't find what you're looking for, contact Festo support with the product number and your application. They'll help you interpret the specs, or point you to a different product family if that's a better fit.

Checkpoint: no certificate, no acceptance. That's a contract requirement now.

Step 7: Run a practical validation test

Paper specs don't always mean the part works in real life. I run two quick tests on every new material or new supplier:

  • Tubing: pressurize to 1.5× the rated pressure, hold for 30 seconds, and check for bulging, leaks, or stress whitening.
  • Rods and bowls: a simple bend test around the specified mandrel radius. If it cracks or stress-marks visibly, it's out.

Run these before you commit to a large order. The most frustrating part of my job is discovering a problem after 10,000 units are in production.

Common Mistakes to Avoid

  1. Comparing 'nylon' with 'plastic' as if they're different categories. They aren't. Compare specific resin families.
  2. Using tensile strength as the only criterion. A material can be 'stronger' yet crack under impact or abrade quickly.
  3. Ignoring moisture effects in nylon. Datasheet values are for dry-as-molded conditions. Real-world humidity changes the picture.
  4. Accepting 'equivalent' materials without verification. 'Equivalent' is not a spec. If it's not in the datasheet, it doesn't count.
  5. Skipping wall thickness checks. Even a small inconsistency can cause failure in plastic bowls or tubing under pressure.

When to Call the Manufacturer (and When Not To)

You don't need to call for an off-the-shelf tubing replacement. But if you're choosing material for a safety-critical application, or if operating conditions are at the edge of standard specs, get a second opinion.

Good manufacturers tell you when something isn't their strength. A vendor who says 'this isn't our specialty—here's who does it better' earns trust for everything else. I'd rather work with a specialist who knows their limits than a generalist who overpromises.

So, is nylon stronger than plastic? It depends on which plastic and what you mean by 'strong.' Use the checklist above, verify what actually arrives at your dock, and you'll avoid most of the failures I see on a daily basis.