Flaring aluminum tubing?

[Jokester]

I've got some 3/8" aluminum tubing that I'm using for a water bypass.  Is there any trick to flaring this?  Should it be single or double flare?  It will carry antifreeze and water at about 18 psi.  

thx,

.bjb

[art.flame]

just a 45 degree flare you could use a AN-fitting you can;t dubbel flare alu
only copper

[unklian]

Single flare is plenty.
If it doesn't want to flare without cracking,
you will have to anneal the end.