Which PEX Pipe Needs an Expansion Tool?
Only PEX-A needs an expansion tool. It is made to stretch and then shrink back around a fitting, so it is often called expansion PEX, and its joints are called expansion fittings. PEX-B and PEX-C are normally joined with crimp or clamp rings, which do not use an expander.
VEVOR CEP401-18BLBest overall
DEWALT DCE400BLight bare tool
DEWALT DCE410Largest pipe capacityPEX-A Is the Expansion Type
PEX-A is manufactured in a way that gives the tubing a strong shape memory. When you stretch the end of the pipe, it wants to return to its original size. Expansion fittings rely on that behavior to make a tight joint.
That is why people search for "expansion PEX" or "PEX expansion fittings." They are almost always talking about PEX-A. The expansion tool is what stretches the pipe end and a reinforcing ring so the fitting can slip inside.
PEX-B and PEX-C do not have the same stretch-and-recover behavior. They are usually joined with crimp rings, clamp rings or push-style fittings. If you own PEX-B or PEX-C, you do not need an expander, and you should not try to use one on it.
How an Expansion Joint Works
The process is simple once you see the order of steps. A typical expansion joint goes like this, though you should always follow the instructions from your pipe and fitting maker.
- Cut the pipe square and clean, with no burrs or debris.
- Slide an expansion ring over the pipe end.
- Insert the expansion head into the pipe and ring, then squeeze the trigger. The head opens in stages and rotates slightly between each stage.
- Remove the head and push the fitting into the pipe right away.
- Hold the joint for a moment while the pipe and ring shrink back down around the fitting.
- Let the joint set for the time the maker specifies before pressurizing the system.
PEX Types Compared
This table shows how the three common types are usually joined. Joint methods can vary by brand, so treat it as a general guide.
| PEX type | Typical joint | Needs an expansion tool? |
|---|---|---|
| PEX-A | Expansion ring and fitting (many systems also offer other fitting styles) | Yes, when you use expansion fittings |
| PEX-B | Crimp or clamp ring on an insert fitting | No |
| PEX-C | Crimp or clamp ring on an insert fitting | No |
How to Tell Which PEX You Have
Do not guess from the color. Pipe color usually tells you hot or cold use, not the PEX type. The printed line on the tubing is the reliable place to look.
Read the markings along the pipe, or check the packaging and the maker's data sheet. If you are matching an existing system, look at the fittings too. Expansion fittings have a visible ring on the pipe end, while crimp and clamp joints use a different style of ring.
- Look for "PEX-A" or "Type A" in the printed line on the pipe.
- Look for a reference to ASTM F1960, which is the standard for cold-expansion fittings.
- Check the size and temperature ratings printed on the tubing.
- If the markings are worn off, ask the maker or supplier before buying fittings or a tool.
What to Check Before Choosing an Expander
Once you know you have PEX-A, the next step is matching a tool to your job. Our best PEX expansion tool page puts six products on one spec sheet so you can compare the details side by side. These are the points that matter most.
Start with pipe size. Five of the six tools stop at 1 in, and only the DEWALT DCE410 lists 1.5 in. The low end varies too. Four of the six list a range starting at 0.375 in, and two start at 0.5 in, including the VEVOR CEP401-18BL.
Next, confirm the PEX type. The VEVOR lists PEX-A only, and the DEWALT listings name Type-A tubing. The Milwaukee listings in our data do not state a type, so check with the maker before you buy.
Then count what is in the box. Three of the six listings include no batteries, and three include two. Only the VEVOR and the Milwaukee 2532-22 list 3 expansion heads and a carrying case. Weight runs from 3.9 lb to 11.64 lb, which matters if you work overhead. You can see how each product lines up on our PEX expansion tool comparison.
Safety Notes
Wear safety glasses when expanding pipe and when cutting it. Keep your fingers clear of the expansion head and the ring, because the head opens under force and can pinch.
Battery tools also need care. Use only the battery and charger the maker names, and do not charge a battery that is damaged or wet. If you work on a ladder or in an attic, set up stable footing first, since an expander is awkward to hold with one hand.
Shut off and drain the water before cutting into an existing line. Never use open flame near PEX pipe or fittings, and keep the tubing away from hot surfaces. Follow the maker's instructions for any lubricant or setting time.
Frequently asked questions
Can I use crimp fittings on PEX-A?
Often yes, since many PEX-A systems also offer other fitting styles. Check that the fitting and tubing are rated to work together, and follow the maker's instructions. Expansion is only required when you choose expansion fittings.
Do different pipe sizes need different expansion heads?
Yes. Heads are sized to the pipe. The VEVOR listing, for example, includes 3 heads for 1/2 in, 3/4 in and 1 in tubing. Check which heads come with a tool and which you would need to add.
Does cold weather affect expansion joints?
It can. Pipe usually takes longer to shrink back in cold conditions, so allow more setting time before pressurizing. Check your pipe maker's guidance for the temperatures it covers.
Why does a listing say bare tool?
A bare tool has no battery or charger in the box. On our spec sheet, three of the six products list zero batteries, so you would need compatible batteries of your own.