The available copper waste pipe, unlike other pipe compositions, actually measures 2 inches in diameter. I see in the home improvement center that the 2 inch ABS is larger than 2 inches.
I'm going to use ABS for the shower waste pipes. It looks like most showers use 1-1/2 inch plumbing.
The sewer pipe coming out of the slab is cast iron, and a copper waste pipe (from a utility sink nearby) Y's into it using a copper elbow. A 2 inch rubber union (the kind with hose-clamps) connects the copper elbow to the cast iron Y. I could replace the copper elbow with a Y (copper?) and run the ABS into that.
How can I mate the ABS to the copper pipe or Y? Are there adapters to go from one material/size to another (ie, 2 inch copper to 1-1/2 inch ABS)?