I'm glad someone felt the responsibility of informing others about the harmful effects of smoking with foil. I feel therefore, it is my responsibility to caution everyone to avoid using copper in the assembly of homemade smoking devices. I don't remember the exact damage it does to you, but speaking from personal experience, it fucks up your lungs.
As tempting as the plumbing aisle of your local hardware store is, do not use copper fitting or pipes! Steel, stainless if available works best, but as a general rule if it is colored, stay away.

Peas out