How thick should the bar be? If it's okay with a rather thin one, you might even use solid iron or at least a thick-walled tube and then cut out a radius template from a piece of chipboard and bend against it, for example?
I was considering taking a regular 15mm water pipe and pressing it up against the ceiling, which is curved with (basically) the same radius that the rod should have. Could it work, or is the pipe too elastic so it will spring back? 15mm might be too thick to bend by hand anyway. Otherwise, maybe MaZtoR's suggestion is the simplest solution...
The problem as I see it is that the pipes are a bit springy.
If you make a bending template, you have to over-bend the pipe slightly to get it the way you want it.
A mechanical workshop is certainly the simplest and possibly most convenient, but perhaps not the most fun.
A more interesting solution is:
1 A stable board that does _not_ flex.
2 Draw a suitable inner radius on the board.
3 Place spacers that are as high as the pipe's diameter.
4 Attach a beam on top of the spacers.
5 Add some sort of end fixture for the pipe on one side.
Now you have a template to bend the pipe after. The template compresses the pipe to avoid pipe wrinkles.
But I'm mostly speculating, but that's roughly how I would go about it.
However, I would expect it to take one or two attempts, and since pipes aren't free, it might very well be cheaper to go to the mechanical workshop.
If you make a bending template, you have to over-bend the pipe slightly to get it the way you want it.
A mechanical workshop is certainly the simplest and possibly most convenient, but perhaps not the most fun.
A more interesting solution is:
1 A stable board that does _not_ flex.
2 Draw a suitable inner radius on the board.
3 Place spacers that are as high as the pipe's diameter.
4 Attach a beam on top of the spacers.
5 Add some sort of end fixture for the pipe on one side.
Now you have a template to bend the pipe after. The template compresses the pipe to avoid pipe wrinkles.
But I'm mostly speculating, but that's roughly how I would go about it.
However, I would expect it to take one or two attempts, and since pipes aren't free, it might very well be cheaper to go to the mechanical workshop.
I think you'll have a hard time finding a workshop that has such a large bending radius. Usually, free bending is used when bending such large radii with a small diameter (I'm in the tube bending industry), which means you "press" the pipe against a radius with a bending machine... Anyway, my tip is to either find a workshop (sheet metal workshop) and roll the radius or (the cheaper) alternative, find something with a diameter of about 1000 mm (because the pipe will spring back), fill it with sand as someone previously pointed out (to prevent the pipe from buckling), take a longer piece of pipe than you need and bend it against the diameter (preferably get someone to help you so you can "pull" on each end) and then cut off the ends that haven't acquired a radius.
Are you going to have a diameter as small as a water pipe? 15mm type? If so, you can insert a solid 12mm round bar inside a chrome pipe, making it easy to bend without creases and adding some stability..