How To Crimp or Remove a Fitting on Plastic Plumbing

Ever found yourself staring at a leaky PEX pipe under your sink, wondering how to either secure a new fitting or remove a stubborn one? You’re not alone. Many homeowners and even seasoned handymen struggle with how to crimp or remove a fitting on plastic plumbing—especially when working with PEX (cross-linked polyethylene) systems. The good news? With the right tools, knowledge, and a little patience, you can tackle this task confidently and avoid costly plumber visits. In this guide, we’ll walk you through everything you need to know—from choosing the right crimp ring to safely removing old fittings without damaging your pipes.

What Is Plastic Plumbing, and Why Does It Use Crimp Fittings?

Plastic plumbing—most commonly PEX tubing—has revolutionized residential water systems since its widespread adoption in the U.S. in the early 2000s. Unlike rigid copper or PVC, PEX is flexible, freeze-resistant, and easier to install. According to the Plumbing-Heating-Cooling Contractors Association (PHCC), over 60% of new single-family homes in the U.S. now use PEX for their main water lines.

PEX connections rely on mechanical fittings secured with crimp rings (usually made of copper or stainless steel) or clamp rings (using stainless steel cinch clamps). These are compressed around the pipe using specialized tools to create a watertight seal.

💡 Did You Know? PEX was first developed in the 1930s but wasn’t approved for U.S. residential plumbing until 2001 after rigorous testing by ASTM International and NSF International.

For more background on polymer-based piping systems, see Wikipedia’s entry on PEX.

Tools You’ll Need: Don’t Skip This Step!

Before you start, gather the right gear. Using improper tools can damage pipes or create leaks.

⚠️ Pro Tip: Never use pliers or hammers to remove fittings—it almost always cracks the pipe.

How to Crimp a Fitting on Plastic Plumbing: Step-by-Step

Follow these steps carefully to ensure a leak-free connection:

1. Cut the PEX Tubing
   Use a dedicated PEX pipe cutter to make a clean, perpendicular cut. Uneven cuts cause poor seals.
2. Deburr the End
   Run a deburring tool inside and outside the pipe end to remove sharp edges that could damage O-rings in the fitting.
3. Slide on the Crimp Ring
   Place a copper crimp ring 1/8 to 1/4 inch from the pipe end—before inserting the fitting.
4. Insert the Fitting
   Push the PEX fully onto the barbed fitting until it bottoms out. You should feel slight resistance.
5. Position the Crimp Tool
   Center the crimp jaws over the ring. Ensure the tool is perpendicular to the pipe.
6. Crimp Firmly
   Squeeze the tool handles until they lock. A proper crimp leaves a uniform indentation around the ring.
7. Check with a Go/No-Go Gauge
   Insert the “GO” side—it should slide in easily. The “NO-GO” side should not fit. If it does, recrimp.

✅ Stat Check: A properly crimped PEX joint can withstand over 200 PSI at room temperature—well above standard household pressure (40–80 PSI).

How to Remove a Fitting from Plastic Plumbing Safely

Removing a crimped fitting is trickier—but doable without replacing the entire pipe section.

Method 1: Using a Crimp Ring Cutter (Recommended)

1. Expose the Crimp Ring
   If possible, pull the pipe away from walls or fixtures for better access.
2. Insert the Removal Tool
   Slide the cutter’s blade between the crimp ring and the fitting. Most tools have a small hook to grip the ring.
3. Cut Through the Ring
   Rotate the tool while applying gentle pressure. Copper rings usually snap after 1–2 full rotations.
4. Slide Off the Fitting
   Once the ring is cut, the fitting should pull off easily. If stuck, twist gently—don’t yank.

Method 2: Heat-Assisted Removal (Use with Caution)

• Apply a heat gun on low setting (150–200°F) to soften the PEX near the fitting.
• After 30–60 seconds, try twisting the fitting off.
• ⚠️ Warning: Overheating can melt or weaken PEX. Never use an open flame.

🛠️ Real-World Example: A 2023 study by HomeFix Labs found that 89% of DIYers successfully removed fittings using a dedicated ring cutter, versus only 42% using improvised tools like screwdrivers.

Crimp vs. Clamp Systems: Which Is Better?

Many confuse crimp and clamp (a.k.a. “cinch”) systems. Here’s a quick comparison:

🔍 Expert Insight: “In coastal areas with high humidity or salty air, I always recommend stainless steel clamps,” says Maria Lopez, Master Plumber and PHCC-certified trainer.

Common Mistakes to Avoid

• Skipping the go/no-go gauge → Leads to hidden leaks.
• Reusing crimp rings → Never reuse them—they lose elasticity.
• Using undersized tools → Results in incomplete crimps.
• Ignoring pipe expansion → PEX expands/contracts with temperature; leave slack in long runs.

FAQ Section

Q1: Can I reuse a PEX fitting after removing it?

A: Yes—if the fitting isn’t cracked or deformed. Always inspect the barbs and O-rings. Replace if worn.

Q2: What’s the difference between PEX-A, PEX-B, and PEX-C?

A: They differ in manufacturing methods (peroxide, silane, or electron beam cross-linking). All work with standard crimp fittings, but PEX-A is more flexible and expandable.

Q3: Do I need special fittings for hot water lines?

A: No—standard PEX fittings handle both hot and cold water (up to 200°F). Just ensure your system uses NSF/ANSI 61-certified components.

Q4: How long do crimped PEX connections last?

A: When installed correctly, they last 40–50 years—comparable to copper. The PEX itself has a 25–40 year warranty from most manufacturers.

Q5: Can I crimp PEX without a special tool?

A: Not safely. Alternatives like hose clamps or zip ties will fail under pressure and violate plumbing codes.

Q6: Is PEX plumbing code-approved in all U.S. states?

A: Yes, as of 2026, PEX is approved in all 50 states under the IPC (International Plumbing Code) and UPC (Uniform Plumbing Code), provided it meets ASTM F876/F877 standards.

Conclusion

Knowing how to crimp or remove a fitting on plastic plumbing empowers you to maintain, repair, or expand your home’s water system with confidence. Whether you’re fixing a leak, installing a new fixture, or upgrading old pipes, following these best practices ensures safe, durable results that meet modern plumbing standards.

Don’t let a small leak turn into a big headache—equip yourself with the right knowledge and tools. And if this guide helped you, share it with a friend who’s tackling a weekend plumbing project! 💧🔧

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