How to Cut Pex Pipe in 5 Steps

Are you eager to flex your PEX skills? Also known as cross-linked polyethylene, PEX is a type of flexible plastic used instead of older copper and galvanized steel pipe in modern plumbing projects. PEX is used when building new homes and remodeling older homes with outdated forms of piping. This guide will show you what you need to know about how to cut PEX pipe.

Choosing the Right Tool to Cut PEX Piping

PEX pipe is dense and challenging to cut without the right tools. The size of your piping will help you choose the right cutting tool, as the thicker the pipe is, the denser and harder to cut it will be. Here are some of the top choices:

• Scissor-type PEX cutter: These cutters have two blades that meet in the middle or a single blade that acts like a guillotine against a solid or notched base. They’re easy to use and require hand strength due to the pinching motion of the cut. They’re affordable (around $10–$20) and available in most hardware or home improvement stores.

• Pipe cutter: Pipe cutters look like pruning shears or have sharp cutting wheels and plastic grips for cutting round, dense pipes. They come in various sizes, so choose one that fits around the diameter of your PEX tubing. Most cost $10–$40, but professional-grade cutters can be more expensive.

• Ratchet cutter: Ratchet cutters have longer handles, giving you more leverage for a cleaner cut with less effort. They’re best for larger diameter PEX piping and cost $20–$100, depending on the size and quality.

• PEX crimp ring cutter: A crimp ring cutter has a narrow head that fits between the pipe and crimp ring, allowing you to cut and remove the ring without damaging the pipe. You’ll find this cutter for $10–$100 or more.

• Utility knife: Utility knives aren’t the best tool, but you can use one if there are no other options. Hold the knife at a 90-degree angle to the piping. Watch where you place your fingers and hands, cut away from yourself, and work slowly to get the most even line possible.

Don’t use a saw, as the jagged teeth will leave jagged edges on your piping, which can be a safety hazard and will not give you a tight seal. Call a plumbing repair service near you for help with this process. They’ll have the tools and the know-how to do the job right.

How Do You Know You Need New PEX Piping?

New PEX piping is needed when you add new plumbing during a remodeling project or home addition. Additionally, it may be time to upgrade to PEX because your home's existing piping is degrading. Some telltale signs that you need PEX piping can also be signs of serious plumbing issues. For this reason, it's wise to bring in a plumbing professional to diagnose the issue before assuming that a tubing swap will fix the problem. You might need to install new PEX pipes if you notice:

• Low water pressure

• Odd noises or sounds of running water

• Discolored water caused by rusted copper or steel pipes

• A metallic taste or smell coming from your water

• Leaky faucets

• Running toilets

• Visible signs of corrosion

If you have an older home with copper or steel pipes, you may want to proactively update your piping before issues occur. It's a well-known fact that dangerous metals can contaminate drinking water if pipes begin to corrode. Heating or boiling water cannot remove these corrosive elements from your home's water supply.

How to Cut PEX Pipe

Cutting PEX pipe is far easier than learning how to cut metal pipes or solder copper pipes. However, precision is still every bit as important. Throw on your safety goggles to dive into how to cut PEX pipe yourself.

Assemble Your Supplies

Get started by assembling your supplies. To cut PEX pipe, you'll need only your piping and a pipe cutter. Your pipe cutter will be essential for cutting straight lines without exerting much force. You should also pick up an inexpensive deburring tool for the last step.

Selecting your PEX piping is the slightly more difficult part. That's because plumbers use a color system to identify which lines carry hot and cold water. While color doesn't denote any differences in piping structure or composition, it does create a blueprint for anyone viewing your plumbing system. Here's a cheat sheet for PEX colors:

It's perfectly fine to pick white or gray because you want to use the same color for everything. However, you should avoid using just red or blue for the entire system. Likewise, you should avoid randomly mixing red and blue.

Finally, select PEX pipe with the correct diameter. The standard sizes for PEX pipes are 3/8, 1/2, and 3/4 inches. With PEX, size references the outside diameter of the pipe. This distinction is important because most other pipes are measured by internal diameter. As a homeowner, it's helpful to know that 1/2-inch PEX suits most residential applications. However, tighter spaces may benefit from 3/8-inch PEX.

Measure Your PEX Pipe

You’re free to purchase PEX coils in any length you want. To get started, straighten out your tubing as much as possible over a flat surface. One trick for straightening out PEX that is curling is to fold the piping upward in the opposite direction to work out the kinks.

Next, measure your piping using measuring tape. The industry standard is adding an inch to ensure you're never stuck stretching your PEX between fittings. The extra inch also allows the piping to contract and expand with different water temperatures.

Mark Your Measurements

Mark your intended cutting line with a pen or marker. Make sure the marking won't rub away. After measuring a few times, draw your line exactly where you intend to cut.

Cut the PEX

Insert the portion of your PEX tubing that you intend to cut into the mouth of your cutting tool. Ensure that the line you're using as your cutting mark is directly under the tool's blade. Hold the pipe firmly in place until you feel ready to cut.

When ready, squeeze the cutter tool as steadily and firmly as possible to get a clean cut. You should feel the two sides of the tool squeezing together so that the mouth of your tool is closing in over the tubing. Continue squeezing until the blade has gone completely through the tubing. This means squeezing the handles as far as they can go.

You can expect the first squeeze to create a clean cut. However, you may need to "squeeze and twist" the cutter in a downward motion to complete your cut. If you don't see a clean cut when you release the PEX tubing from the cutter, simply open the mouth of the tool to restart the process.

Deburr Your PEX Piping

Removing sharpness from the interior and exterior edges of your freshly cut pipes is called deburring. You can deburr PEX pipes using a simple deburring tool from a hardware store. To deburr PEX, simply slide the deburring tool at an angle along the edge of your piping to scrape away burrs and other debris.

Common Mistakes People Make When Learning How to Cut PEX Pipe

While cutting PEX pipe is relatively straightforward, little details can come back to haunt homeowners if they aren't handled properly. What PEX pitfalls should you watch out for? Check out this guide to common PEX mistakes.

Not Deburring PEX Piping

As covered above, deburring is the final step to cutting PEX pipes. Many people skip this step if they don't have any obvious jagged spots on their pipes. However, sharp burrs can actually cause leaks and poor fittings because they prevent a water-tight seal from forming.

Not Testing Angles as You Go

Don't do your PEX cutting in a big batch without stopping! Between each cut, test your pipe fitting to confirm that you're getting a clean edge. While you might be tempted to speed through your cutting, you'll save time by adjusting each piece as needed instead of trying to correct several poor cuts. This is an essential step for threading pipes correctly, and it will save you time later.

Not Using Proper Cutting Tools

A pipe cutter is a great investment that only costs a few dollars. People sometimes try to save a buck by using whatever cutting tools they have around the house. You may think that something as powerful as a circular saw could work even better than a pipe cutter because it's so powerful. In reality, circular saws, hacksaws, and similar tools have serrated blades that can leave your pipes riddled with burrs.

Not Diagnosing a Problem Correctly

New PEX won't automatically fix every issue. If you're looking into how to cut PEX pipe because you need to fix a copper pipe leak, faucet leak, or some other issue, it's smart to have a plumber or local faucet repair pro come in to assess the situation before you start disassembling pipes and fixtures. With plumber costs ranging from $45 to $200 per hour, most homeowners will find that the peace of mind that comes from getting an expert opinion allows them to make informed choices.