How to Install a Copper Air Line

Copper air lines are used in cases where air pressure must be delivered to a piece of equipment or an appliance which is in a permanent location. They offer greater strength and service life than plastic air lines. Copper air lines generally fall into two categories: rigid copper and soft copper. I'll deal here with the simpler lower (20 pounds per square inch or less) air pressure soft copper installation.

Things You'll Need

• Soft copper tubing
• Pipe cutter
• 2 sets of compression fittings (nut and ferrule)
• Wrench
• Cleaning brush
• Teflon or thread tape

Instructions

Installing a soft copper air line

1. Find the size of the fittings you wish to connect together with your copper air line. (your appliance and your pressurized air source). If these fitting sizes are different, purchase an adapter fitting to adapt the larger fitting to match the smaller.

2. Measure the length of tubing you will need between the points being connected. Allow for long curves and avoid tight turns or excessive bends, as these easily turn into crimps or weak points in the line. Add five to 10 percent to the length. You can trim at the second connection if you have too much, but you can't add onto your line if you come up short. With experience, you'll be able to judge the first cut more accurately.

3. Purchase a coil of soft copper tubing with an outer diameter to match the size of your connections and greater than the length measured in Step 2. Purchase compression fittings of the same size as your tubing and end connections.

4. Using the pipe cutter, cut the copper pipe to the measured length plus a margin. Be sure the cut is clean and perpendicular. Use the ferrule (the hollow metal bead) that came with the compression fitting to verify the cut is round and the ferrule will fit snugly.

5. Place the soft copper tubing between the points being connected, ensuring any bends are as smooth as possible, particularly at the ends. If at all possible, the last four inches before the line reaches an end should have no bend.

6. Slip the compression nut over the first end to be attached and then slip the ferrule to rest snugly about 1/4 inch from that end of the copper line.

7. Clean the fitting the air line is about to attach to (if needed). Inset the air line into the fitting (the ferrule may slip back a bit as you seat the line in) and bring the nut up to loosely secure the line.

8. Repeat Step 5 at the other end.

9. With the line loosely secured at both ends, trace the length of the line. Correct any tight bends or kinks in the line.

10. Remove one end of the air line. Tape the threads of the receiving connector with Teflon or thread tape if appropriate. Use your wrench to tighten the nut and secure the connection.

11. Repeat Step 8 at the other end.

12. Slowly pressurize the air line. Look for any jerking of the line under pressure, you may need to support the line with anchored straps or hangers. Listen for air leaks.

Tips & Warnings

• Route your line to take advantage of any existing supports or add a support at least every three feet.

• Treat any pressurized system as a potential explosion. Poorly secured air lines may break loose and fling fittings. Be sure you use a tubing cutter and not a hacksaw or clippers. Your tubing cut must not deform the roundness of the tube.