I just installed a new bathroom vanity countertop (St Paul by Home Depot) and installed a new Moen faucet. I used plumbers putty to install the drain and the drain leaked. I took it apart and used more putty than the first time and I still see a leak coming through between the nut and the threads. I didn't try silicone yet because I know it's a bear to clean up. Should I go the silicone route? If I do how long should i let it dry before testing everything? Should I apply silicone to parts other than around the underside of the waste seat? BTW the parts are all plastic and upon disassembly appear to be in good shape, I'm not sure what the sink is made of but I know it's some sort of man-made material. Any help would be greatly appreciated, thanks.

take the drain off the sink and clean up all the putty. apply 100% silicone caulk under the drain flange, onto the bottom of the sink opening and ontop of the big rubber gasket. tighten it well. clean up the silicone with denatured alcohol BEFORE it sets up. you can run the water as soon you want. no need for the caulk to cure..
i have never (i repeat) never had a leaker when using silicone. especially given that the drain parts are all plastic and can not be tightened too much.

If you want to avoid any clean up use plumbers putty under the drain flange and silicon on the threads and big rubber washer.

Thanks for the reply, I'm gonna go the silicone route, it worked on another drain in my house. I've tried putty 3x and I'm living the definition if insanity. Just wondering, I saw a youtuber use silicone and he went nuts with it, under the flange, under the stopper, on the threads of the nuy and even at the bottom of the nut (where my leak is). Is this overkill?

A little dab on the threads where the rubber washer compresses against the threads is all that required to keep it from leaking externally. You want a little something under the flange, putty or silicon, to prevent the water from going down into the drain when the pop up is in the closed position.

just enough silicone so a small amount squeezes out when you tighten the nut.
cleaning up silicone that squeezes out from under the flange is a snap. wipe it right away before it sets up. denatured alcohol (if you have any) will clean away the residue...

I put silicone under the flange, between the bottom of the sink and the rubber gasket, on the threads of the nut and under the nut, I'm going to let it dry for 3 hours then test it, wish me luck, thanks for the advice!



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I've got it all back together, now to let it dry and test it in 3-4 hr. I can't see how it can go wrong, I've caulked every hole imaginable. This is the last faucet to replace to get rid of the crappy stuff they gave us with the house, figures this one would give me fits.

as i said earlier, no need to wait. turn the water on.