One of the guys here in our office is a big fabricator and designed these tubing clamps. They are really slick! He builds sizes for up to 2" OD (TC1), 3" OD (TC2), 90 deg fixed (TC90), and even tab holders (TBH)! Pretty neat stuff, not real pricey!

Link: http://www.vansantent.com/tube_positioners.htm

http://www.vansantent.com/images/tube_clamp2sm.jpg http://www.vansantent.com/images/tbh.gif

Link:http://www.vansantent.com/tab_holders.htm