Joining copper pipe with compression fittings is a popular method that doesn't require soldering, making it accessible for many DIYers. This method relies on mechanically compressing a ring (olive or ferrule) onto the pipe and into the fitting body to create a watertight seal.
Here's a step-by-step guide on how to make a secure joint using compression fittings:
Tools and Materials You'll Need
Before you start, gather the necessary tools and materials:
- Copper pipe
- Compression fitting (correct size for your pipe)
- Pipe cutter
- Deburring tool or file
- Measuring tape and marker
- Adjustable wrenches (two are often helpful)
- Emery cloth or wire wool (optional, for cleaning pipe ends)
- Pipe inserts (essential for soft copper or chrome-plated pipe)
Step-by-Step Guide to Joining Copper Pipe with Compression Fittings
Follow these steps carefully to ensure a watertight and reliable joint:
Step 1: Prepare the Pipe
- Measure and Mark: Measure the required length of pipe and mark it clearly.
- Cut the Pipe: Use a pipe cutter to make a clean, square cut at your mark. Rotate the cutter around the pipe, tightening it slightly with each rotation until the pipe is cut through. Avoid using a hacksaw, as this can create a jagged or angled cut.
- Deburr the Pipe: The cutting process will leave a burr (raised edge) on both the inside and outside of the pipe. Use a deburring tool or the reaming blade on your pipe cutter to remove both the inner and outer burrs. A file can also be used for external deburring. A smooth pipe end is crucial for a good seal.
- Clean the Pipe End (Optional but Recommended): Lightly clean the outside of the pipe end where the fitting will sit using emery cloth or wire wool. This removes any dirt or oxidation that could compromise the seal.
Step 2: Assemble the Fitting Components onto the Pipe
Compression fittings typically come in three main parts: the body, the nut, and the olive (also called a ferrule).
- Disassemble the Fitting: Unscrew the nut from the fitting body and slide the nut and the olive off the body.
- Slide on the Nut: Slide the compression nut onto the prepared end of the copper pipe. Make sure the threads on the nut are facing towards the end of the pipe.
- Slide on the Olive: Slide the compression olive onto the pipe after the nut. The olive should be positioned so it will sit between the nut and the fitting body when assembled. Ensure you put the nut on before the olive; otherwise, you won't be able to tighten the joint.
- Insert Pipe Insert (If Applicable): If using soft copper pipe or chrome-plated pipe, insert a pipe stiffener (insert) into the end of the pipe. This prevents the pipe from deforming when the olive is compressed.
Step 3: Insert the Pipe into the Fitting Body
- Insert the Pipe: Take the end of the pipe, with the nut and olive now on it, and push it firmly into the compression fitting body. Push the pipe in as far as it will go until it bottoms out inside the fitting.
- Position Nut and Olive: Slide your nut down over the olive towards the fitting body.
Step 4: Hand Tighten the Nut
- Initial Tightening: Begin to tighten the compression nut onto the threads of the fitting body by hand. As noted in the reference, you'll find when you tighten it by hand that it's still loose and the pipe will still be able to come out easily at this stage. This hand-tightening step just brings the components together.
Step 5: Wrench Tighten the Nut
- Secure the Fitting Body: Hold the body of the compression fitting steady with one adjustable wrench. This prevents the fitting or the pipe from twisting during tightening.
- Tighten the Nut: Use a second adjustable wrench to tighten the compression nut onto the fitting body. This is the critical step where the olive is compressed onto the pipe and against the fitting body, creating the seal.
- Tighten the nut firmly. A common guideline is to tighten about one full turn (360 degrees) after the point where you start feeling significant resistance (snug by hand or where the wrench first bites).
- Do not overtighten. Overtightening can damage the olive, the pipe, or the fitting, leading to leaks. It can also deform the pipe.
- Check for Security: The pipe should now be securely held by the fitting and should not be easily moved.
Step 6: Test for Leaks
- Restore Water Pressure: Once the joint is made, restore water pressure to the pipework.
- Inspect the Joint: Carefully check the compression joint for any signs of water leaks.
- Address Leaks: If you notice a small weep, try tightening the nut a little bit more (perhaps another quarter turn). If the leak persists after careful tightening, the joint may need to be disassembled and redone, ensuring the pipe was properly prepared, the components were in the correct order, and the olive wasn't damaged.
Following these steps ensures you create a secure and watertight joint between copper pipes using compression fittings.
