Sink caulking is an important part of ensuring a watertight seal around fixtures.
Learning how to apply sink caulking is a handy skill in do-it-yourself home maintenance. Caulk creates a pliant seal for gaps between the sink and countertop to maintain a mildew-free, watertight work space. Whether the sink is a new addition or the old caulking has grown too hard or too spongy to keep water from seeping into the joints, applying sink caulking is an important step toward keeping the sink and counters clean and looking new.
The U.S. Department of Energy recommends household silicone caulk for sealing joints between bath and kitchen fixtures and tile. It adheres well to non-porous substances and stays flexible. A tub and tile acrylic-based caulk is another good choice in a sealant. Acrylic is watertight and flexible with the added benefit of being resistant to mildew.
Remove the old caulk first with needle nose pliers. If the old caulk is too hard to lift out easily, warm it up with a hair dryer before using the pliers, being careful not to scorch the sinks surface. Use a razor blade to cut into the edges of the caulk before lifting it out with the needle nose pliers. New silicone caulk will not adhere over the old caulk, so it is important to remove all of the old sealant.
Wash the seams on the sink with alcohol to get rid of any lingering caulk. Since it is an area exposed frequently to water, go over the area with a solution that destroys mildew, such as one part household bleach added to three parts water. Leave the area to completely dry before applying the new sealant to keep mildew from becoming trapped within the seams. Most kitchen and bathroom caulks have mildew resistant chemicals pre-added to them as an extra precaution. Wear rubber gloves and safety goggles when using bleach and have paper towels and a small pail of water within reach.
After the surface around the sink has been thoroughly cleaned of all of the old caulk, load the caulking gun to apply the fresh sealant. Caulking guns utilize a ratcheting plunger to push the sealant out of the tube when the trigger is pulled. The Consumer Energy Center of the California Energy Commission offers these tips on how to load a caulk gun:
Caulk guns may vary a bit in the way they deploy the sealant. One type employs a small button to release a plunger and allows the pressure within the caulk tube to release. Another type of gun releases the pressure by turning the plungers rod on end. Caulk is also available in easy-to-use squeeze tubes.
Caulk is sticky and messy. It may be especially difficult for the inexperienced caulker to lay down a good line. There are two ways to move the caulking gun along a seam: either push forward on the angle of the nozzle or pull against it to shape the bead.
Apply a line of caulk at a 45-degree angle with the nozzle flush on the seam line. Go slowly, keeping the speed, angle and pressure consistent for a nice, even bead. Release the trigger of the caulking gun immediately at the completion of each line to reduce weeping from the end of the nozzle. For shallow seams, pull the caulk gun toward you. For deeper seams, push the nozzle away for the caulk to better penetrate inside the seam.
Once the bead is down, draw a wet finger (the moisture helps the finger move over it smoothly) along the length of the seam to press the caulk down into the joint between the sink and the counter to seal it in. Avoid applying too much caulk. Lay down the beads sparingly so that the caulk will not make ridges or jagged sides. Wipe the caulk off your finger with the paper towels.
Finish the end of a line by pushing the nozzle into a corner. Twist the nozzle and lift it off. Caulk applied correctly around the sink will prevent water from leaking down inside the seams and spreading mildew. Wait at least 24 hours for the caulk to dry before using the sink.