--Wall thickness is one difference; the other is the amount of
tooling that's available to work with it: tons of pipe benders, for
instance, but tube benders that won't kink the material are rare and
expensive.

--
"Steamboat Ed" Haas : Heartily sick of
Hacking the Trailing Edge! : "oldies" stations!
http://www.nmpproducts.com/intro.htm
---Decks a-wash in a sea of words---