What is an advantage of a double flare on aluminum tubing?

• A. Ease of construction
• B. Can be applied to any size and wall-thickness
• C. More bulky than single flare
• D. More resistant to damage when the joint is tightened

Answer: (D)

The advantage comes from the reinforcement built into a double flare. By forming two folds, the flare edge gains extra material and a broader seating surface, so when you tighten the nutted joint, the clamping force is distributed more evenly across the flare and into the tube wall. This reduces the risk of deforming, cracking, or crushing the flare—something that’s a particular concern with softer metals like aluminum. The result is a more durable, leak-free joint that stands up better to tightening, vibration, and pressure changes.