Installed two new Delta bathroom sink faucets. This requires that you remove and install the "tailpiece" with the pop up stopper. This plastic tube is 1 1/4 inch in diameter, where it meets the 1 1/2 inch PVC pipes. So, you use the adapter to seal between. No problem.

Wait. Why is that water coming down the outside of the tailpiece? Down the threads, past the black rubber ring gasket that I put there. I used silicone sealant at the decorative ring. How is water getting from inside the pipe to outside the pipe? Is it through those cross-molded holes?

And, in case you are wondering, I am so good I did this on TWO sinks.

How do I prevent these leaks?

Check the rubber gromets on the compression fittings. Also i prefer paste piping sealabt to thread tape.

Common problem with the plastic pop-up assemblies. I use silicone caulk on the threads to prevent this.

Water is getting out through the holes that are meant to accept the overflow water.

You use plumbers putty under the rim of the strainer where it seats upon the sink. And I usually put a bead of putty along the black gasket which pushes upward via the big nut tightening from beneath. Also a smearing of pipe dope over the putty and black gasket.

They have to seal plumb to the sink. "Square, plumb, and level". Those plastic ones are a PITA. I've a brass pop-up assembly in the box just in case mine craps out.

Usually on a commercial application I'll use a grid strainer with no pop-up.

On a faucet replacement you have the option of leaving the pop-up assembly alone. The new pop-up rod will usually tie into the old assembly.

^^^^ This. Plumbers putty is needed in any faucet install.

I think you use silicone on cast iron sinks. Plumbers putty for others.

Yep, very common.

Putty or silicone under the top ring in the sink, either is fine.

Pipe dope on the threads underneath before pushing up the big rubber washer, and pipe dope on the face of the washer where it contacts the sink.
Silicone will work here but will be much harder to remove if service is needed later. Do not use putty on the threads / washer underneath.

quote:

Originally posted by 9mmnut:
I think you use silicone on cast iron sinks. Plumbers putty for others.

18 years of residential plumbing, and electrical work here. I've done a bunch of this!

Either or is fine... but if anything you have that backwards actually. "Stainless" Plumber's Putty was always used on cast iron historically, for over a hundred years.

Silicone is best for those man made fake marble sinks as they won't tolerate much pressure when tightening the drain to sink. More than hand tight may lead to cracking in the future. Most have a warning label affixed, warning against over tightening. Putty doesn't work well with out a good and tight fitting, it may work loose and eventually fail.

Silicone is more foolproof in general, but has two major issues... both cleanup and removal for service down the road is harder.

quote:

Originally posted by cparktd:

quote:

Originally posted by 9mmnut:
I think you use silicone on cast iron sinks. Plumbers putty for others.

18 years of residential plumbing, and electrical work here. I've done a bunch of this!

Either or is fine... but if anything you have that backwards actually. "Stainless" Plumber's Putty was always used on cast iron historically, for over a hundred years.

Silicone is best for those man made fake marble sinks as they won't tolerate much pressure when tightening the drain to sink. More than hand tight may lead to cracking in the future.

That's good to know for future reference. (Note to self: No fake marble sinks.)

Plumber's putty and drains... *sigh*. Here are some things I've learned, as an amateur plumber, over the years:

• Use fresh plumber's putty. That nearly-dried-out container from the last time you did this? Toss it.
  
• More isn't necessarily better. Too much is as bad as too little.
  
• It doesn't take much, but it must be evenly applied. No thin/low spots or wrinkles.
  
• If you get it right, it doesn't take excessive tightening for it to do its job.
  
• That rubber piece on the bottom of bathroom sink drains accomplishes nothing in the way of sealing--no matter how hard you tighten things down.
  
• Fake chrome plastic drain assemblies are worthless junk. Go to a real plumbing supply and get a metal drain with real chrome plating.
  

quote:

Originally posted by ensigmatic:

• Use fresh plumber's putty. That nearly-dried-out container from the last time you did this? Toss it.
  
• More isn't necessarily better. Too much is as bad as too little.
  

During the winter, it'll take hot water in the drain and further snugging up to get the putty seal right.

Too much on a kitchen strainer pushs the gasket out. Learned that the hard way. Still making that mistake!