6 simple steps to connect copper pipe to Pex (2023)

If you're a homeowner, chances are you'll have to connect copper pipe to cross-linked polyethylene (PEX) pipe at some point. It's a common repair that plumbers are called upon to do, and it's not as difficult as it might seem.

In this article, we will show you how to connectcopper pipeon the PEX pipe so you can do this part of the plumbing yourself.

Tools you will need to connect the copper to the PEX pipe

  • I push inAdjustment
  • Wire brush
  • Pipe cutter

If using welded fittings:

  • Blowtorch
  • Flow
  • Metal glue
  • Crimp Rings/Cinch Clamps
  • Cinch Tool

Step by Step Guide: How to Connect Copper to PEX Pipe

6 simple steps to connect copper pipe to Pex (1)

Step 1 – Decide which method to use

There are two basic methodsconnecting copper pipe to PEX pipe. The first uses weldingcopperto PEX adapters and crimp rings or pinch clamps to strengthen the connection.

The other method is relatively new and uses push-in fittings. It is the easiest type of installation and requires no welding or special tools and can usually be attached in seconds.

The disadvantage of push-in fittings is that they are not as strong as welded connections and are not recommended for use in high pressure applications.

(Video) How to Connect PEX to Copper Pipe: The Plumbers Secret- Episode 3

We recommend using push-in fittings for new DIYers who are new to welding and more traditional welding fittings for more experienced people who already have the necessary tools for this.

If you're not sure which method to use, we recommend starting with push-in fittings or even calling a professionalplumber.

Step 2 – Cut and prepare the tubes

Before connecting the copper pipe toPEXpipe, you must cut the pipes to the required lengths. Use a tape measure to measurethe pipesand mark the cut line with a marker, pencil or chalk.

We recommend using a plain pipe cutter for copper pipe and a PEX pipe cutter for PEXpiping. You don't need to use power tools for these pipes because both PEX and copper are relatively softmaterialswhich can be easily cut.

When using a pipe cutter, place the cutting wheel on the pipe cutting line and tighten the tool so that it is snugthe pipe. Then start spinning the tool aroundthe pipe, constantly tightening it as you rotate.

When using PEXtubingcutter, be sure to cut the pipe at a 90 degree angle. This will help create a tight seal when connecting the pipe to the fitting. If you don't cut it straight, but at an angle,the connection will be loose, and can leak over time.

Step 3 – Prepare the Copper Tube

Once you cut itcopper pipe,you will need to prepare it for welding. To do this, you will need to clean its interior and exteriorthe pipewith a wire brush. This will remove any dirt or debris that could prevent weldingthe pipe.

(Video) Convert Your Copper To PEX | Church Flip | Episode 11

If the cut is not particularly clean, you can peelthe pipeusing sandpaper or a deburring tool. It will get rid of all jagged edges,ensuring a stable connection. If you are using sandpaper, you can wrap it around a piecewoodfor easier handling.

As with all things sanding, start with a lower grit sandpaper and work your way up to a higher (finer) grit sandpaper as you go. It will result in better deburring and a smooth finish.

6 simple steps to connect copper pipe to Pex (2)

Step 4 – Connect the Copper Tube to the Fitting

Once the pipe is ready, you can connect it to the fitting of your choice. If you use a soldered adapter, you need to solder it to the pipe.

To do this, you will need a welding torch, flux and solder. To begin, apply flux to the inside of the weld adapter and the outside of the pipe. This will help the solder adhere to the pipe.

If you don't use flux, the solder won't bond to the pipe and fitting and your joint will be weak and prone to leaks.

Now, insert the end of the copper tube into the fitting and start soldering by heating the connection. Then put solder on the joint, continue to heat it until the solder melts, and connect the copper tube to the fitting.

Finally, let the fitting cool for a few minutes before attaching the PEX pipe.

(Video) How to Join Plastic and Copper Pipes | Plumbing Guide for Beginners

If you are using a push-in fitting,the process is much simpler. This type of fitting is also called a push-to-connect fitting or simply a push fitting and is almost exclusively made of brass. First, push the copper pipe into the fitting until you feel it is connected.

The connection should be tight and secure, but if it isn't, you can always remove it and push it back in. If the connection is still not tight enough, you can add a small amount of pipe sealant to the end of the copper pipe and slide it back in.

Then, depending on the exact push-in fitting you have, you may need to insert a PEX stiffener into the end of the PEX pipe. Finally push the PEX pipe to the other side of the fitting and here you have the copper pipe connected tothe PEX pipe!

Here's a quick video showing how to use push-in fittings.

Step 5 – Secure the PEX Connection (Optional)

If you used the solder adapter, you must secure the PEX connection with either crimp rings or pinch clamps. Both of these options require specialized tools - a crimping tool for crimp clamps and a PEX crimping tool for crimping rings.

Both options do the job just fine, butthere are some differencesbetween them. Cinch clamps are more expensive (including the rings themselves and the tool to fit them), but installation is much easier, especially in tight spaces, and the cinch clamp tool is more versatile than the ring crimper.

(Video) 6 SHARKBITE Mistakes NOT To Make! | GOT2LEARN

This is because the crimping tool is universal for all sizes of all PEX pipe, while the crimping ring tool is sold in different sizes depending on the size of pipe you will be fitting. So if you have multiple sizes of PEX pipe, you will need to purchase a set of crimping ring tools that can accommodate all sizes.

It quickly adds up to the total price, and while there are some universal options, it's rather expensive.

The process of attaching a watertight seal to the connection is much the same with both, crimp rings and pinch clamps. Place the ferrule or clamp on the PEX pipe where the fitting joins and tighten with the tool.

Step 6 – Check for leaks

No matter what type of fitting you've used, it's important to check for leaks after connecting the pipes. For example, if you have connected your new PEX pipe to a copper pipe that leads to a valve connected to your toilets,shower, thesink, you can suffer significant damage if the connection leaks.

The best way to check for leaks is to turn on the water supply andcheck for leaks at the connection connections. If you see any leaks, you will need to disconnect the hose and fittings and start over.

Extended Tips

6 simple steps to connect copper pipe to Pex (3)
  • When using solder fittings, it is important to use lead-free solder. Lead-based solder is no longer allowed to be used in potable water applications.
  • Before connecting the PEX pipe to the solder adapter, solder the coppertubingon the component. This will prevent the PEX pipe from melting if you did it the other way around.
  • When using crimp rings or clamps, make sure they are properly secured.A loose connection can lead to leaks.
  • When using push-in fittings, it is important to follow the manufacturer's instructions. Some brands of push-in fittings require the use of a special tool to secure the fitting to the pipe.
  • Always turn off the water before working on the pipes.
  • If you are not sure which method to use or if you are having problems connecting the pipes, we recommend that you call a professional plumber.
  • You can also use screw adapters that have male or female fittings to connect copper tubing to PEX tubing.
  • The female threads are on the inside of the adapter and the male threads are on the outside.


Copper pipe connection withPEX pipeit's not as difficult as it may seem, especially if you use a push-in adapter. In this case, all you have to do is slide the tubes to the ends of the fitting, and that's it.

If you are going to use a welded part, you should:

(Video) How to Connect PEX to Copper Plumbing Pipes

  1. Apply flux to the outside of the copper tube end and to the inside of the fitting
  2. Insert the copper tube into the fitting and heat the joint with a blowtorch.
  3. Apply solder to the connection and heat it with a blowtorch until it melts and secures the connection
  4. Allow to cool before using or installing

If you have any questions about connecting different types of pipes together, let us know in the comments!

Related Posts on Pip's Island Home:

  • Pex “A” vs Pex “B” vs Pex “C” vs Pex “AL”: What is the difference?
  • 5 simple steps to join metal pipe to PVC
  • 7 simple steps to join threaded PVC pipes
  • 5 Simple Steps to Cut Pex Pipe
  • 7 simple steps to blast copper pipe


1. Push & Connect fittings, how to use and install
(Waterline Products)
2. How to Install PEX Pipe in Bathrooms (Quick Tips) -- by Home Repair Tutor
(Home Repair Tutor)
(Silver Cymbal)
4. Connect faucet to PEX the easy way
(Guns & Gears)
5. How to Join Copper & Plastic Pipe Plumbing Tutorial
(Skill Builder)
(Think Reno)


Top Articles
Latest Posts
Article information

Author: Tish Haag

Last Updated: 23/09/2023

Views: 5479

Rating: 4.7 / 5 (47 voted)

Reviews: 94% of readers found this page helpful

Author information

Name: Tish Haag

Birthday: 1999-11-18

Address: 30256 Tara Expressway, Kutchburgh, VT 92892-0078

Phone: +4215847628708

Job: Internal Consulting Engineer

Hobby: Roller skating, Roller skating, Kayaking, Flying, Graffiti, Ghost hunting, scrapbook

Introduction: My name is Tish Haag, I am a excited, delightful, curious, beautiful, agreeable, enchanting, fancy person who loves writing and wants to share my knowledge and understanding with you.