Posted on: 10 May 2016
If your sink drain still leaks after replacing everything that can be replaced, you should try switching from plumbers putty that is designed to seal the space between your drain cup and your sink with silicone.
Although silicone smells terrible until it is sufficiently cured, and is not as malleable and easy to work with as plumbers putty, it can provide a tighter seal and not deteriorate over time as quickly as plumbers putty.
You'll need to take apart the sink drain and through clean off all of the plumbers putty before you can apply the silicone, so you'll need a few things to complete the job.
What you will need:
A tube of bath and kitchen silicone sealant
This is not the long type of tube that is dispensed with a caulking gun to apply silicone around windows and other outdoor areas. This type of silicone is found in the plumbing or bath department of your local home improvement store and resembles a wide tube of toothpaste.
You'll need to loosen the compression nut at the top of the "J" shaped sink trap below the sink to remove the drain cup and pipe.
Rags or paper towels
You need to clean out all of the plumber's putty before applying the silicone. It will likely be smelly and slimy to the touch after degrading from exposure to water for long periods, so you may choose to wear plastic gloves.
It's a good idea to have a fan available to provide additional ventilation as you reattach the drain components before allowing the silicone to cure. The strong smell of ammonia may cause watery eyes and irritation to your breathing passages. You should keep doors and windows open until the smell dissipates as the silicone cures.
Removing the drain assembly
You will begin by loosening the large studded nut that holds the drain gasket against the bottom of your sink drain. These nuts are only tightened by hand, so you shouldn't need any tools to loosen it.
When it is completely loose, allow the nut and the gasket to slip down to rest on the curve of the sink trap. You will then loosen the compression nut at the top of the trap with the adjustable wrench.
You can then push up on the drain pipe and remove the pipe and drain cup that rests inside the slight depression in the sink.
Cleaning out the putty and applying the silicone
This depression, the bottom rim of the drain cup, and the area below the sink where the gasket met the sink will need to be completely cleaned of any buildup of plumbers putty.
You must be particularly vigilant in removing all of the putty, because the silicone will not be able to provide a complete seal if the area is still contaminated with putty.
When you are ready to apply the silicone, you must also be ready to reconnect the sink drain components, because silicone can set too quickly and become rubbery.
Apply a 1/4" bead of silicone around the depressed area of the sink around the drain, then slip the drain pipe through the hole and push the drain cup down into the silicone.
Under the sink, pull up the gasket and the large securing nut from around the sink trap and secure the gasket and nut to the bottom of the sink. Hand tighten only. This will pull the drain cup down farther into the silicone and help to strengthen the seal.
Tighten the compression nut with the adjustable wrench to secure the drain pipe to the sink trap.
You should wait until the next day to allow the silicone to cure, even if the smell has dissipated. However, check the manufacturer's recommendations on the side of the tube. They may have more specific cure times related to temperature and humidity at the time of application.
If you feel you cannot do this on your own, however, contact plumbers in your area who can complete the project for you.Share