Bending conduit

[TheEngineer]

Nice! Then it will blend right in with all those octagonal hay bales you always see...

Ahem...please see Exhibit A:

Can you make an octagon out of PVC pipe and eight 45deg elbows?

If the octagon isn't round enough, you could "round it off" with 1/8" or so round bar on top of the straight sections of PVC...or you could use sixteen 22.5deg elbows for a more round shape, but those suckers are expensive compared to a standard 45deg

 

[Cameramonkey]

Thinking about it more, my brain says two sticks of pvc, 45 degree at the top. If the base is the right distance and the two sides are the right length, you will have nearly a constant arc. I have a tent that uses a similar principle. tension holds an arc.

 

[Leo]

We were trained and tested in making bends like that when I was an apprentice. The bender we used was a hickney, that is a cruder tool than a normal radius shoe type bender. It involves calculating how many bends you want (the more the better) and how many degrees needed that would be divided by the bend number. 15 evenly spaced bend points was about standard to make a large radius 90% bend. I never made a circle, but made many bends to go around a petroleum tank or to follow the curve in an assembly line conveyor. Lots of time setting up and measuring, and we did it with rigid or emt conduit. I'll bet if you searched the greenlee website it would have the instructions. My Benfield books are long gone.

 

[Snapdragon]

Would something like this help? Segment Bends

 

[wolfman]

How about using PVC electrical conduit? My electrician did a job with some recently that required some really complex custom bends, and he had some sort of heater he used to soften it just enough to form the bends.

 

[jlupacch]

Wheatland makes 20' EMT 20 Foot EMT & Rigid Electrical Conduit - Wheatland Tube and I believe others do as well.

To get a large radius circle you will have to do concentric bends. Multiple small degree bends spaced evenly.

Here is a site that should help. Segment Bends

Search concentric bends or segment bends for more info.

 

[jlupacch]

Twenty four 15 degree bends should give you a circle

 

[eric001]

You could recreate the shape from the "bale blind" link by using 1/2 or 3/4 inch PVC. First, get 20 foot lengths of whichever. Second, instead of a wooden upright support, just cut the PVC where the supports would be and put 45's in on both sides of the blind. Don't use a 45 at the top, just let the pipe bow. If you used 2 45's on each pipe, you'd end up with 3 sections of pipe for each loop--ought to make it easy to put together, even if it was dark. You could also cut the longest piece to preference for a loop of the right height to suit your needs.

If you're wanting to take it apart and put it back together in cold weather, I'd suggest 1/2 inch rather than 3/4. PVC gets brittle and cranky when it's cold out, and bigger sizes seem to get crankier faster. Either way, I think you might be able to anchor the pipes at the base with something like flag holders if you were looking for a good initial angle outwards.