Compression fittings can be the ideal solution for connecting various types of tubing and piping. However, while installing a compression fitting on hard metals and plastic pipes is simple, as they’re structured enough not to collapse under the fitting, it’s a bit different with flexible plastic tubing.
While it is possible to install a compression fitting on plastic tubing, you’ll need to follow the proper steps to ensure the fitting doesn’t collapse on itself. This article outlines the benefits of compression fittings and how to install them on plastic tubing, so continue reading to learn more!
Perks Of Compression Fittings
Compression fittings are a suitable option for various settings, as they offer a range of benefits and work well with numerous materials. Here are a few reasons why compression fittings are a perfect fit (especially for at-home projects):
Soldering Isn’t Necessary
Soldering is an essential step in various fittings, but not with compression fittings. These fittings don’t need the help of solder, making them suitable for areas with gas nearby or snug spaces. They’re a safe alternative to soldered fittings in various situations, making them a popular pick.
Easy To Use
Since soldering isn’t necessary for a compression fitting installation, installing them is DIY friendly. Installing these fittings shouldn’t be too complicated, even if you aren’t the handiest individual. Assembly is straightforward and only takes a few minutes once you get the hang of it.
And the best part? They’re just as easy to remove! You can easily unscrew them when you need to disassemble them. In most cases, you can reuse the compression fitting. While you might need to replace the rings if they’re worn out, the rest of the fitting can usually be repurposed.
Perfect For Mixed Materials
If you’re working with multiple piping or tubing materials, your connection options are limited. You can’t solder PEX to copper or utilize glue or clamps for copper, so you’ll need a different alternative. Compression fittings are a perfect choice in these situations.
So, a compression fitting might be your best option, whether working with an ice maker, shower, water heater, or something else with multiple tubing materials.
Can You Use A Compression Fitting On Plastic Tubing?
Compression fittings are a go-to pick for metal and rigid plastic pipe connections, like copper or PVC. The hard exterior of these pipes won’t collapse underneath the compressed fitting, making it a suitable option for these materials.
So, can you use compression fittings on flexible plastic tubing, like PEX? Yes, you can. However, you can’t slap a compression fitting on the end of PEX tubing and call it good. Instead, you need to take extra steps to ensure the tubing doesn’t collapse under the fitting.
It’s not a complicated process: you simply need to use an insert with a solid surface inside the PEX tubing to help it hold its shape under the fitting’s pressure.
Parts Of A Compression Fitting
There are three primary parts in a compression fitting: a nut, a plastic compression ring, and ferrules. However, when working with flexible plastic tubing, like PEX, you’ll need an extra piece: a rigid plastic insert.
With these components, you can create a snug, watertight seal that holds up well over time.
What Type Of Compression Fitting Should I Use On Plastic Tubing?
It’s essential to choose the proper type of compression fitting for your project. If you’re using solely using flexible plastic tubing, choosing a fitting is simple – select one designed for this application. However, if you’re using mixed materials, the correct fitting varies.
Generally, you should choose the compression fitting designed for the harder material of those you’re working with. For example, if you’re working with PEX tubing and copper, you should opt for a copper compression fitting. Or, if you’re using PEX and PVC, a PVC compression fitting is your best option.
The same rule applies to the internal fitting, so use the same concept. Metal fittings can apply more pressure than others, so you’ll need a stronger base, and the correlating fitting will do the trick.
How Do You Install A Compression Fitting On Plastic Tubing?
Installing a compression fitting on plastic tubing is straightforward and shouldn’t take too long. Here’s what you’ll need to complete the project:
- Compression fittings to match your tubing – choose the internal diameter that fits the tubing
- Appropriately sized interior fittings for the tubing
- Sealants required by the inserts (usually none, but be sure to double-check)
- Shears or utility knife
- Measuring tape
Prepare The Tubing
First, you need to prepare the tubing for installation. Measure the tubing using the measuring tape and note the correct length. Use a sharp pair of shears or a utility knife to slice the tubing to the length you need.
Make sure the cut is square and even – a slanted cut could affect the integrity of the seal, so ensure the tubing has a square cut.
Disassemble The Fitting
Once your tubing is ready to go, disassemble the fitting. Separate each piece of the fitting, including the nut, ferrule, body, and stiffener, setting each piece within reach. You can set them on a cloth or in a small bag if you need to step away from the project for a moment.
Install The Fitting
Now, it’s time to install the fitting. Start by inserting the internal fitting into the tube. Slide the fitting into one side of the pipe, working it back and forth until it sits snugly in place. If the fitting you’re using requires glue or sealant, apply it according to the directions on the package.
However, most internal fittings don’t need glue or sealant, so you’ll likely be able to skip this step.
Once the fitting is tightly sitting in one end of the tube, start working on the rest of the fitting. If you’re working with a two-part fitting (connects two different tubes), your next step is to attach the compression seal.
Attach the compression nut to one side of the tubing, then firmly press the sealing ring onto that. Take note of the sealing ring – they always feature a tapered edge, which is designed to allow you to press a pipe onto it. So, be sure the sealing ring is situated correctly, with it facing the compression fitting, not the nut.
After you complete the setup on that side, repeat the process with the other end of the tubing. Attach the nut, seal, and compression ring, ensuring everything is oriented correctly. Next, screw the compression fitting onto the tube.
Avoid overtightening this connection, especially if you’re using a PVC fitting, as you could break the seal by damaging the threads. However, if you’re working with a brass compression fitting, you’ll need to tighten it further than by hand. To secure it firmly, tighten the fitting with a wrench. Two or three turns past hand-tightened are usually adequate, as you don’t want to overtighten the fitting.
Repeat the process on the other end of the compression fitting. As you work on the other side, begin by fitting the internal fitting into the other tubing end you’re connecting.
Check Your Handiwork
Once you complete the fitting, be sure to check your handiwork. Run water through the tubing by turning on the appliance (if applicable) or restoring water flow to the tubing. Watch carefully for leaks, keeping an eye on the fitting in particular. If everything remains dry, you’re good to go!
You’ll need to retrace your steps to find the issue if there’s a leak.