Cross-linked polyethylene, better known as PEX, is a go-to form of home plumbing, as it’s much easier to work with than other materials, like copper, PVC, and CPVC. Unlike its rigid counterparts, PEX tubing is flexible and malleable, making it easy to install, even for beginners. However, while it’s easy to work with, there are a few do’s and don’ts for installation, especially when it comes to bending this material.
This article explains the ins and outs of bending PEX tubing, along with a detailed guide for several methods, so continue reading to learn more!
Is It OK To Bend PEX?
While bending PEX piping is doable, you need to be careful with how you bend the material. If you improperly bend it, the material may develop crimps, causing issues down the line. So, while you can bend PEX piping, you need to do so correctly. There are three ways you can bend PEX pipe: using clamps, bend supports, or a 90-degree elbow.
Using PEX clamps, you can install the piping at various turns, including tighter turns and wide, gradual turns. The clamps themselves are small plastic clips featuring attached nails, which allow you to secure the PEX pipe by nailing the clamps over the top of the tubing.
The clamps offer support through the turn, enabling safe changes in direction.
PEX bend supports are another option for changing directions with PEX tubing. These supports are small ¼-turn plastic or metal pieces, some with nails built into the design. The piece fixes the tubing in place, enabling a 90-degree turn.
These supports are ideal for achieving the tightest allowable turns in PEX tubing (90 degrees), as they allow a sharp turn without folds or crimps. Of course, the turn radii vary from one tubing diameter to the next, as each can support different turn radii. For example, if you’re working with ½-inch PEX tubing, you can usually get away with no more than a 5-inch turn radius.
PEX elbows are another option for achieving tight 90-degree bends in PEX tubing. The fitting is L-shaped and connects two pieces of PEX. So, instead of bending one continuous piece of PEX tubing, these fittings connect two straight pieces of PEX.
There are a few types of 90-degree elbow fittings, including push-fit and crimp-fit systems. With the push-fit systems, you simply push the tube directly into each end of the elbow. This method doesn’t require any tools save for a PEX cutter and removal tool. The second option requires you to push the tubes over a brass fitting, where you’ll crimp a brass ring over the end using a specialized tool.
Is It Better To Bend PEX Or Use Elbows?
Generally speaking, it’s better to use elbows for sharp turns but gradual bends where sharp turns aren’t necessary.
So, if you need to pivot the PEX tubing a full 90 degrees, it’s usually best to use elbows. While you can use bend supports to achieve a 90-degree turn, elbows don’t require a sharp bend from the pipe itself. Instead, they use two straight pieces of tubing, which avoids potential stress on the tubing altogether.
However, bending PEX is perfectly suitable in most frame homes, as there’s plenty of room for gradual bends. If you decide to bend the tubing instead of using elbows, ensure you supply the proper support. So, use clamps or bend supports to fix the tubing in place.
Remember to follow the product manufacturer’s recommendations for the tubing’s bend radius. Generally, the recommended parameters fall within five to eight times the tubing diameter, so ensure you follow these guidelines. If you bend the tubing too sharply, it might fold or crimp, causing issues with the system later.
How Do You Bend PEX Water Pipes?
The exact process of bending PEX tubing hinges on the type of support or fitting you plan on using. The sections below outline the process for three common types, including clamps, bend supports, and 90-degree elbows. So, once you decide which support of fitting you’re using, skip to that section and follow the steps.
Bending PEX With Clamps
If you plan on using clamps to support the bends in your PEX tubing, here’s what you’ll need for the project:
- Straight edge
- PEX tubing
Once you gather your materials, follow these steps:
- Since you’re nailing the clamps to a particular surface, you’ll need to examine it for inconsistencies. Generally, you need to use flat, sturdy wood as the nailing surface. So, inspect it for warping and instability.
- Once you confirm the wood is good to go, use a straight edge (or framing square) and a pencil to measure and mark the intended curve of the tubing. Generally, you can mark the angle with a straight line as opposed to drawing the curve, as this will simplify the process of determining the correct angle.
- Use a hammer to nail one PEX clamp to the wood surface on one end of the curve. Be careful not to damage the plastic sleeve on the clamp as you secure it to the wood.
- Slide the PEX tubing into the first clamp. If you’re working with an existing pipe, you’ll need to nail the clamp over it, so be careful not to puncture it.
- Carefully bend the tubing into the correct position to match the intended angle. Go slowly as you bend the tubing, as sharply bending it can cause damage. As you bend the tubing, keep one hand on the tube extending from the first clamp to prevent it from stressing the clamp.
- Once you bend the tubing into position, secure the second clamp over the tubing. Nail it into place using the hammer, ensuring you don’t unintentionally puncture the tubing. Once the nail is securely in the wood, release your hold on the tubing.
Bending PEX With Bend Supports
Bend supports are another excellent option for securing PEX tubing, so if you plan on using them, here’s what you’ll need:
- Heat gun
- Bend supports
- PEX tubing
When you’re ready to start, follow these steps:
- Before you begin bending the tubing, use a heat gun for heating the area. Keep the heat gun on the lowest setting and gently heat the tubing to make it easier to work with and avoid crimping. Alternatively, leave the roll of tubing in a warm room for a few hours.
- After you warm the PEX, you’ll need to work quickly. Gently push the tubing into one end of the bend support.
- Gently and slowly curve the tubing around the bend support, so it fits against the device. Don’t bend too quickly, as it could cause the tubing to crimp and fold.
- Once the tubing curves to the correct angle, gently push the end of the tubing into the opposite end of the support. If it’s in correctly, the tubing should snap into place.
Bending PEX With 90-Degree Elbows
If you’re working with sharp corners, you might decide to use a 90-degree elbow to complete the task. Here’s what you’ll need for this project:
- Clean cloth
- Indelible marker
- Push-fit elbows
- PEX tubing
- PEX cutter tool
Once you gather your materials, follow these steps:
- First, ensure the end of each tube is square, clean, and smooth. Use a clean cloth to remove gunk from the end of the tubing and square off the ends using a PEX cutter tool (as necessary).
- Use an indelible marker to note the insertion or stop point on the end of each tube. You’ll need to use the manufacturer’s pipe insertion depth chart to get the proper insertion depth, as different brands have varying depths. Mark the end of each tube.
- Once you mark each tube, insert the tube into the push-fit elbow. Simply grasp the elbow in one hand and the tube in the other, then firmly push the tube into the elbow. The barbs inside the push-fit connector will dig into the PEX tubing, holding it in place and creating a secure connection.
- Repeat the insertion process on the other side of the elbow.
Frequently Asked Questions (FAQs)
Is It OK If PEX Kinks?
When installing PEX tubing, it’s essential to handle bends and corners properly to avoid kinks and folds in the tubing. Although bending the tubing is fine, kinks and folds are not. These folds and kinks create a weak spot in the tubing (where the material folds on itself) and impede water flow.
So, if the tubing kinks while you’re working with it, you need to fix it before moving forward. Generally, installing a fitting or joint at the kink is the best way to remedy the issue, as you can remove the problem altogether.
What Causes PEX Failure?
Although PEX is much easier to work with than rigid forms of plumbing, it can still be tricky if you’re unfamiliar with it. In cases where PEX plumbing fails, the most common culprit is improper installation. For example, sharp bends and kinks in the tubing cause high stress on the wall of the pipe, raising the risk of oxidative degradation.
Aside from user errors, PEX failure might also be accelerated by prolonged exposure to sunlight. The material’s molecular structure may begin to disintegrate in sunlight, causing weak points in the tubing.
What Color PEX Should I Use For Hot Water?
For the most part, PEX colors correlate with a specific water temperature. While this isn’t totally necessary, it can make future projects easier, as you can quickly determine which line supplies hot or cold water. Generally, hot water flows through red PEX, while blue PEX moves cold water.