I just installed a new vanity... and when I I connect my sink drain. I have a very tiny slow drip from the plastic drain body... the instructions say put plummers putty arroundthe drain opening and teflon tape over the threads. I have done this twicew and I still have a slow leak. It says to hand tighten the locknut. On the send try I hand tightend then about 1/2 turn with lock pliers but I am afraid of cracking the sink... my plummers puttty is old but pliable... does plummers putty go bad? Any idea what I could be doing wrong? Missing?
Thanks in advance
Ron

Hard to tell which to fix, the assembly mating to the sink or the drain tube. Wrap the drain tube in toilet paper and then turn on the water slowly while you wach with a flashlight. Which got wet first, the tube or thesink connection above it? BTW putty does go bad by getting progessively harder and harder, make it soft for a few minutes by heating in a microwave for 20 seconds

Roll the plumber's putty into a 1/4" roll. Put around the lip of the drain. Hand tighten to squeeze it out. Remove the excess.

No teflon tape at the bottom. If you use anything there, just use some plumbers silicone grease.

The seal is made with the plumber's putty.