if you want a c or s rail, don't weld...please. it won't be smooth. Use a pipe bender (don't know the real name for it)....you measure out lines on a straight piece of pipe....closer together makes a tighter arc, farther apart, more mellow...you gotta do some math for it. The thing looks like a big jack. No compressors or anything, it's bent by hand. Ask around at local shops (or welders) and see if they'll do it for ya....it'd be expensive to buy.
The troll stole my Santa!