I have always used plumber's putty to seat a drain to the sink or tub. With the new "plastics" the recommendation is for one to use silicone instead because the plumber's putty is oil-based and presumably will cause degradation of the "plastic". The silicone does not seem to seal as well, particularly for shower and vanity drains which require twisting. Anyone have any suggestions?

We have always used silicon jel for sealing drains on marble lavatories because the oil in the putty would leach out into the marble. They must have changed plastic since I retired because we always used putty on our tub and lavatory drains. When installing a lav or tub/shower drain the lip of the drain shouldn't "twist". If you let it twist it will spin out the seal. Regards, Tom

I suspect that most plumbers use plumber's putty still. I do like to follow the manufacturer's specs generally, but in this case, I have had problems doing so. What I mean twisting is, like in the case of a lav sink, you have to position the drain so the pop-up is positioned towards the back and thus the drain can shift around while you get it positioned properly.

The acrylics used in today's plumbing fixtures are a whole new ball game. Petroleum based sealers, like plumbers putty, react with the plastics, and will at best discolor the drain or fixture and at worst cause the drain to break or distort. When only a silicone or latex sealer is called for, it should be used. The same applies to piping; don't use regular (petro based) pipe thread compound on PVC pipe. Any plumber that used putty when only silicone/latex is called for is doing his customer a disservice. I replaced numerous drains using the required silcone and never had a problem. Make sure everything is clean and dry and put a generous bead in the indentation where the drain sits. The excess will squeeze out when the drain is installed. Wipe the excess going around the drain which will leave a nice seal around the outer edge. Be sure and let the silicone dry thoroughly before using. As Speedball stated, you shouldn't have to "twist" the drain when installing.