is plumber's putty under plastic okay?

I have a plastic American Standard tailpiece for a bathroom sink. The plumbers putty I have has a caution on it: "do not use on marble or plastic."

Does anyone know what kind of putty or caulk I should use under the flange which goes above the sink, which looks like an old (40 years-old?) generic ceramic sink? I'd like to avoid any possible leaks under the flange.

There is at least one company that makes a plumber's putty that won't stain the plastic. It's not that what you have won't work, but that it has oils in it that can leach out and stain the sink. The alternative is to use silicon, but hope you never need to replace it and want to keep the sink!

Thanks, Jim, for helping me "see the light." I had thought the caution referred to a plastic tailpiece, but your post leads me to believe the caution refers to the type of sink (marble or plastic) that the putty should not be used on. If the flange of the tailpiece gets stained on the bottom, it's immaterial to me, although I"m not the expert.

Other than installing the drain into the sink, the parts below it don't normally need any putty. One exception is maybe the fine threads of the tailpiece extension, and there, pipe dope is better. Sometimes, if there is a clog or slow drain, water can seep past the threads. The compression fittings do not need, and often will leak if you use putty on them.

Thing we simpler in the olden days before all of the new materials. Used to be you just made a putty ring for the under side of the the basket and tightened it down. Now you have to be sure there are no conflicts in chemical makeup of the parts.

The putty can attack the chrome plating on the plastic drain and cause it to come off. Usually, plastic drains have a "foam" or rubber gasket to place under the drain "flange" so you do not have to use any sealant.

hj said:

The putty can attack the chrome plating on the plastic drain and cause it to come off. Usually, plastic drains have a "foam" or rubber gasket to place under the drain "flange" so you do not have to use any sealant.

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That makes total sense. My newly replaced faucet sets from American Standard had the fat foam rubber gasket for the drain to sink connection along with all sorts of instructions on not putting any putty there. But how about the faucet fixture (handles and spout) to sink top connections? The AS Cadets I just put in have a plastic base part on them. I, as I've always done (right or wrong but hopefully right), put plumber's putty under the faucet fixtures and tightened them down so there is technically plenty of "putty-to-plastic" happening at that connection. Was that okay to do? If not can someone suggest something as leak-proof and also service-friendly. Thanks so much. I'm learning so much here!