Just to fill everyone in, copper is a NO NO when it comes to heating anything you might breathe in. You can't make any sort of smoking apparatus out of it due to the toxic gases released. You can use it for parts of the device that aren't being heated at all such as, a mouthpiece or body of the device that isn't taking any significant heat that you might breathe.
Having worked in plumbing for many years, I can tell you that when you cut open a roll of soft copper that's fresh from the factory, the inside of the pipe smells like naptha (mothballs). Don't know why but that, alone, should dissuade you.
Yes, please stick to stainless, kanthal, nichrome or any other *known* safe wire.