Below, we’ll show you how to seal a kitchen sink drain using plumber’s putty or silicone. If your sink has been dripping, this is the information for you!
When installing a new sink, an important step is to seal around the drain flange. This will prevent water from leaking under the flange and traveling down the outside of the drain pipe rather than being directed into the pipe.
A leak can sometimes develop if the seal around the flange has deteriorated or if it wasn’t done correctly in the first place. The solution is simple: remove the flange, apply a new sealant, and then reinstall the flange.
This article describes how to seal a kitchen sink drain or bathroom sink drain step-by-step. We’ll also discuss the pros and cons of the two most common sealants used for this project so that you can make an informed choice.
Before beginning, gather the tools and supplies you’ll need to do the job. This handy checklist will help:
- pipe wrench or channel lock pliers
- screwdriver (if the flange is attached with a screw)
- bucket to catch any water when you disconnect the drain
- clean towels
- mineral spirits (for cleaning the flange and fittings)
- utility knife or small putty knife
- caulk gun and silicone sealant or a jar of plumber’s putty
- gloves and any necessary safety equipment
Plumber’s putty has been around for years and is simply a malleable compound, similar to clay, which is used to seal plumbing fixtures.
Here are the steps to a successful job:
- Remove the kitchen sink drain flange. Many flanges have a screw in the middle that can be removed, or the entire flange may turn counter-clockwise to unscrew.
- Thoroughly clean the flange by removing old putty or sealant and dry with a clean cloth. Also, clean the sink drain area where the flange was removed.
- Apply plumber’s putty to the bottom of the flange and press it into place. Some putty should squeeze out around the edges.
- Tighten the flange into place and remove excess putty. Wipe the area with a clean cloth to remove any leftover residue from the putty.
- Test the flange for leaks by filling the sink, putting in a stopper, and allowing water to stay in the sink for about 10 minutes. Check for leaks under the sink. If the drain pipe remains dry, you have solved the problem.
The procedure for sealing a kitchen sink drain with silicone is very similar.
- Remove and clean the flange as mentioned above.
- Apply a quality silicone sealant to the underside of the drain flange. Use steady pressure to place an even bead all the way around the flange. Avoid applying excessive silicone to minimize the amount that will ooze out when replacing the flange.
- Reinsert the flange and gently press it into place.
- Insert and tighten the screw to secure the flange.
- Wipe away any excess silicone with a cloth and mineral spirits.
- Allow the silicone to fully dry. If you find any excess dried silicone, remove it with a putty knife.
- Test the seal by filling the sink with water as mentioned above.
Plumber’s putty is waterproof and works well, but it has a few drawbacks.
Putty does not have adhesive properties; it simply fills the gap between the sink and the flange. Silicone, on the other hand, functions as both an adhesive and a sealant, creating a more powerful and long-lasting connection. This can be especially important in pressurised connections.
A second issue concerning plumber’s putty is that it is not compatible with all materials and can damage plastic pipes. For instance, it should not be used on PVC pipe, ABS (a common black plastic pipe often used for drains and plumbing vents), or acrylic surfaces.
Silicone sealant is compatible with all of the above materials. Choose a good-quality silicone in either clear, white, or a colour that closely matches your sink.
An alternative that is especially handy for making a quick repair is Loctite All Purpose Extreme Gel. This powerful adhesive is fast-setting and will bond to a wide range of materials, including metal, glass, ceramics, and most plastics. Extreme Gel is highly water resistant.