How To Use Compression Fittings With Plastic Tubes
Some folks are familiar with compression fittings. After all, the average household nowadays has at least one compression fitting installed in its water line. Ask them to define what a compression fitting is and they’ll tell you it’s a kind of coupling that creates a robust, permanent connection between two pipes or tubes.
But what most people seem to take for granted about compression fittings is its ability to attach two pipes together made from completely different materials. This is what makes compression fittings so useful around the house. It’s also what makes it popular in the industry setting, especially for joining compressed air connections and high pressure lines. With compression fittings, you can connect a copper tube to a PVC pipe.
A simple compression fitting consists of three parts: a compression seat, compression ring or ferrule, and a compression nut. The compression seat comes in both I and L shapes.
For plastic tubing, compression fittings help stiffen the plastic by providing a metal tubing sleeve at the end of the tube. It should be noted that compression rings can’t be reused. You must cut off the end of the tube if you need to replace an old and rusty compression fitting.
Here’s a step-by-step instruction on how to install a compression fitting on plastic tube:
- Make a clean cut on the plastic tube. Remove any burrs, debris along the circular edge.
- Slide the compression ring and nut first if you’re planning to bend the plastic tubing later on. Make sure the fitting is snug so it won’t let go once the plastic tubing is bent. Avoid bending too close to the compression fitting.
- Lubricate the compression nut threads before putting it together. Make this a constant habit when working with compression fittings on plastic tubing.
- Double check that the nut is pushed all the way through into the compression seat before proceeding.
- Tighten the fitting in two places using a wrench – one on the nut, another on the compression seat.
- Do not over-tighten. When finished, turn the water back on and check for leaks.
A few more tips:
- Use a plastic compression ring for working with plastic pipes and tubes. It’s better than using the metal kind.
- Compression fittings are designed and should only be used once. If it fails or breaks down for some reason, buy a new set and replace everything.
- Solid brass last longer than copper compression fittings but are more expensive. If you need a stronger connection, go solid brass compression fittings.
From here on out you should have no trouble working with compression fittings on plastic tubes. It is an indispensable skill if you want a decent water line in your house without having to spend time and money to hire someone and do the job for you.