I'm just finishing a complete remodel of the bathroom and I'm just hooking up the drain to the sink. I believe I've installed it correctly but I'm still getting a very small leak (after 30sec of running both facets, a small bulb or drop of water slowly appears where the bottom of the sink meets the washer). I'm afraid to tighten it much more because I feel it could crack the sink. I've had it out 3 times to inspect why its leaking. Progressively the leak has gotten better, although it was never more than a small drip, its down to a very slight as mentioned above. The last time I placed a small ring of putty around the washer to try to seal it up, also tightening it as much as I dared. I'm convinced the sink is somewhat warped. I'm at the point where I've tried to correctly do the job and its not working. During this job I've uncovered just about every surprise that the Joe before had skipped every corner. I hate doing anything the wrong way but I almost want to rip my hair out. Is it possible to use a heavy strength waterproof adhesive to seal it in. It barely qualifies as a leak, and there is no pressure on the leak itself.