I installed a heating oil line recently. Code required type L or M
(not refrigeration) tubing, and flare or soldered fittings. I used
some 1/2" OD Type L, and in one place I used a flare fitting. I've
done flares on soft tubing before, but doing this tubing was hard as
heck. It took a lot of torque to get a flare, and the flare was prone
to crack or come out off-kilter. It took several tries to get a
halfway decent flare. Unfortunately, halfway decent was not enough,
and the fitting has developed a slow leak.
Am I doing something wrong? Can type L be flared? Does it need to be
annealed somehow first? Do I need a better tool (the one I have is a
fairly cheap tool)? Or should I solder on a short piece of soft tube
and flare that?

Thanks,

Kelly