I'm trying to replace the drain pipe parts under my kitchen sink. The drain pipe is metal and I want to use plastic parts with slip nuts. How can I securely connect a plastic drain trap to a metal drain pipe?

What's under my sink presently is a mess of pieces whose purpose mostly seems to be to make the wrong lengths of pipes fit. Short extensions of pipes, etc. Some have nuts that screw on with pipe dope, some are rubber with clamps, and there is at least one connection that doesn't have threads, but just a nut that's probably a compression nut. When I was loosening a connection at the other end of that, the compression nut and pipe came loose. That's why I want everything to have threads, because I don't know how that kind of non-threaded connection can be trusted. But I don't really know what I'm doing. via /r/DIY https://ift.tt/2BvwL2c