Hi, I know I can get the pre-made pipe bender online, but I wanted to know how I could do it with a regular pipe bender from Home Depot, Lowe's, or some place like that. I've seen how so use a pipe bender (not done it), but I don't know what angles I would use or how difficult it would be. I was looking at 12-16' wide. That made me think the radius is 8', in a perfect circle, though I am wondering if it is more of an ellipse. 8' is high enough for me.
angle = 90 for one of the four quadrants of the sphere, one pole really.
radius is 8' (16' dia.)
Arc Length is 12.56637' (from an online calculator)
s=r(theta) or something.
But, how do I know how to bend the pipe at a certain angle to get those dimensions with a regular pipe bender? Do I do 30 degrees, 27, 5.49939393, who knows? I didn't want to buy the pipe bender just for a greenhouse, if I didn't have to. No offense to you who sell them. I wanted to learn to use a regular pipe bender.
I used to use an electricians pipe bender day in and day out.
It is complicated enough that I cannot easily describe it.
You can learn to bend arches with them, but that is some next level stuff that I never mastered.
Bending the pipe in three places could give you 1/2 of an octagon, thus emulating a half circle.
The best way to learn is to do, so I would advise getting a small 1/2" bender and sacrificial pipe.
For references, Uglys makes book on conduit bending that will be way too in depth, plus it covers electrical stuff you don't need to know.