Now, look at your new drain pipe (the one connecting the sink’s tailpiece to the wall pipe). It’s probably too long or too short. Hold it in place and dry-fit everything—no glue yet—to see if it lines up.
If it’s too long, cut it with your saw. Sand the edges with a little sandpaper so it slides smoothly. Pro tip: Burrs are the enemy; they’ll make your slip nuts leak like a sieve.
The Secret Sauce: Slip Nuts and Washers
Here’s the part I messed up the first time. Every connection uses a slip nut and a rubber washer. The washer goes on first, cone side facing the pipe. If you flip it, it’ll hiss at you like an angry cat when you turn the water on.
Slide the nut over the pipe, then the washer, then push the pipe into the fitting. Hand-tighten the nut first, then give it a quarter turn with the channel locks. Not too tight! You’ll crack the plastic, and then you’ll be back at the hardware store at 9 PM on a Sunday. Ask me how I know.
