what's the best way of bending this!!

[tessdad]

For tears my Dad and I used a couple of Oaks. Just outside his shop we had two large Oak trees that came up from one stump giving us a nice "V".
Make a paper pattern (I use brown building paper, Kraft paper). Mark of the pipe in equally sections (4"-6") on longer jobs like yours I also number the sections, so as you progress on you can keep track of where you are, this also helps when your making your second piece, as you can tell just what section needs to be tweaked as you lay them on top of each other.
If you do not have the trees in your yard, weld some large diameter pipe (6"+) to anything immobile, bench, truck bumper, etc. We one used a very large wooden cable reel to form matching 5' diameter circles to make a "German Wheel" you see acrobats use these in Circ-de-Sole (sp) shows.

[mribeiro]

I used to have to duplicate 10 or more long curves by hand with a hip bender. Granted this was only alluminum schedule 40, but we did it sometimes with 2" pipe. Takes a lot of practice to keep the twisties out. My first bimini bow (that's what we called them) took me 5 hours to get right. With practice I could do a single boats worth in the same time.

[psychosis]

the best way i can think of achieving what you want to do is as stated, mark out a radius on the floor then use a pipe bender, i have one of these:

http://cgi.ebay.com/0APB0-WHOLESALE-...QQcmdZViewItem

then mark the tube with a pen at 1" increments. line up the middle of the die at each increment and do a set number of pumps on the hydraulics. bearing in mind that as you move along, you're bending the previously bent section a little more. very much about trial and error but can give excellent, smooth, seamless results once you get the knack.