Jack, it is still difficult to double flare annealed stuff.....I would start with a 5 ft stick, flare it, cut it off, flare it again, cut that off, flare it again.....sometimes I burned the entire piece without getting two good flares......learned new words however.

Sometimes, I got lucky and got two flares on the same tube to take....now, I'm scared to ever disconnect those lines.

Pre-flared tubing from the auto supply is much easier.....and cheaper, and better for your blood pressure.

mike