Bong Making question

alright so i am making this sweet bong out of a grand marnier liquor bottle, i already have the drill bits and everything and i was looking at some plumbing pipes and joints today to use as the downpipe and the bowl. Most of them were either brass or copper and none were aluminum. I heard that smoking with copper piping is bad for you, but does anyone know anything more about this. If it is so bad for you, what about brass? because that is a copper alloy. Any help is greatly appreciated cause i want this bong to be awesome.

you can probably use copper or brass for the stem but you should really by a glass bowl