If you choose crimp ring fittings, you will need to purchase a kit that has different sizes of crimp ring tools for around $100 USD. If you use cinch clamp fittings, you can get a cinch clamp tool for about $40 USD. Crimp ring and cinch clamp fittings cost around $10 USD for a pack of 25-50.
A male fitting refers to a fitting that inserts into the threads of the other end of the fitting and screws into them. A female fitting refers to one that covers the threads of the other end of the fitting and screws onto them. If the threads are on the outside of the copper pipe’s fitting, then you need a female fitting on the PEX. If the threads are on the inside of the copper pipe’s fitting, then you need a male fitting on the PEX.
Make sure that the end of the PEX tubing is cut squarely so it will fit evenly over the end of the fitting.
Reposition the ring or clamp if needed by sliding it so it is about in the middle of where the PEX tubing covers the fitting.
If you used a crimp ring fitting, you might need to work your way around the sides, squeezing the handles of the tool as you go, until you get a totally tight fit. The advantage of a cinch clamp over a crimp ring is that you just have to tighten it once.
A PEX expander tool will set you back around $200 USD. They can range in price up to 4 times that much depending on the kit you want. Different kits come with more heads for different diameters of PEX. Expansion fittings cost about $20 USD for a pack of 5.
Male fittings are narrower than female fittings and screw into female fittings. Female fittings are wider and screw on top of male fittings. If the threads are on the outside of the fitting on the copper tubing, then you need a female fitting on the PEX. If the threads are on the inside fitting on the copper tubing, then you need a male fitting on the PEX.
The end of the PEX tubing needs to be cut squarely so it will fit cleanly over the end of the expansion fitting.
PEX has its own “memory”, meaning that it will return to its original diameter after it is stretched out.
Despite being the most expensive, their ease-of-use makes push-fit fittings a good option when you only need to make a few connections of copper and PEX. Push-fit fittings cost at least $5 USD each.
As with other methods, you will need to make sure the end of the PEX tubing is cut evenly so it will fit cleanly into the end of the push-fit fitting.
Make sure that the end of the copper tubing is smooth around the edges before you insert it. You can sand around the end to remove any sharp edges. If the copper pipe has a threaded fitting attached to it, you will need to remove it first. You can cut the pipe just below it to make a new clean opening at the end.
