Connecting flare fittings involves preparing the tubing correctly, flaring the end, and then securing the flared tube end between the fitting body and a flare nut. The process creates a watertight seal without the need for solder or other sealants.
Preparing Tubing for Flaring
Proper preparation of the tubing is crucial for a successful flare connection. Based on the provided reference and standard practice, this includes:
- Resizing: Ensure the tube end is perfectly round. As highlighted in the reference, tubing that is "out of round prior to flaring should be resized back to round." Using a tube resizer tool can help achieve this.
- Cleaning: The end of the tube to be flared must be clean. According to the reference, you should "Clean the tube to be flare. Using an abrasive cloth." This removes any burrs, dirt, or oxidation that could compromise the seal.
- Deburring: After cutting the tube, the inside and outside edges will have burrs. These must be removed using a deburring tool to prevent damage to the flare and ensure proper seating.
Steps for Connecting Flare Fittings
Once the tube is prepared and the end is properly flared, you can proceed with connecting the fitting.
- Slide the Flare Nut: Before flaring, slide the flare nut onto the tube with the threads facing the end to be flared. You won't be able to put the nut on after the flare is made.
- Flare the Tube: Using a flaring tool suitable for the tube size and material, create a cone-shaped flare on the end of the tube. The flare should be uniform and free of cracks or wrinkles.
- Inspect the Flare: Examine the completed flare carefully. It should be centered, symmetrical, and have consistent wall thickness around the cone.
- Position the Fitting: Bring the flared end of the tube together with the flare fitting body. The cone of the flare should align perfectly with the conical seat inside the fitting body.
- Start Threading the Nut: Slide the flare nut down the tube and hand-tighten it onto the threads of the fitting body. Ensure the nut starts smoothly and doesn't cross-thread. Hand-tightening helps confirm proper alignment.
- Tighten with a Wrench: Use a wrench to tighten the flare nut onto the fitting body. The nut compresses the flared end of the tube against the fitting's seat, creating the seal. Tighten firmly but avoid overtightening, which can deform the flare or fitting. Refer to torque specifications if available for critical applications.
Tools You Might Need
| Tool | Purpose |
|---|---|
| Tube Cutter | Cutting tubing to length |
| Deburring Tool | Removing burrs from tube ends |
| Tube Resizer | Ensuring tube is round (as per reference) |
| Flaring Tool Kit | Creating the flare on the tube end |
| Abrasive Cloth | Cleaning tube end (as per reference) |
| Wrenches | Tightening the flare nut onto the fitting |
Following these steps ensures a secure and leak-free connection suitable for various applications, including refrigeration, natural gas, and hydraulics.
