Published on February 19th, 2018 | by Henri0
Rust around sink drain
Q. I have picked up much useful info from your column, web site, and book. But I now have a question for you.
I had a registered plumber install two new American Standard sinks in my bathroom vanity approximately two years ago. I also had new Moen faucet/ drain assemblies installed at the same time.
One of the sinks is developing a rust stain on the white porcelain around the drain. The other sink is fine. I contacted Moen thinking that the drain stopper or the drain assembly was rusting and learned that the particular model which I had installed was plastic and therefore could not rust.
Is the rust coming from the sink basin’s drain opening? Could the sink’s porcelain finish be defective there? If so, could I remedy the problem by removing the Moen drain and using porcelain touch-up paint to coat the area around the drain? Thank you for your help!
A. You have very likely found the source of the problem. Congratulations.
The porcelain finish may not cover the entire drain hole, but plumbers apply plumbers’ dope to set the drain assembly in, which protects the very edges of the drain from being in contact with draining water.
However, I have seen a few cases where the dope was not applied as thoroughly or thickly as it needed to be or the porcelain was very thin, or stopping short of the drain’s edges, and water came in contact with the raw iron edges of the drain.
You could do what you are suggesting, and it may work, but make sure that all the rust is removed or it will come through again. Get some plumbers’ dope and don’t spare it when replacing the drain assembly.by