Caulk is used to fill in the gaps around a sink or other fixture to ensure that it is watertight. If water gets between the fixture and the walls, it won’t evaporate easily and it’s likely to lead to water damage.
This kind of water damage can include mold and mildew, both of which can be harmful to your family’s health. Mold can appear as black, white, or any other color and it usually has a powdery, velvety, or cottony appearance.
If you are concerned that a spot may be mold, some of the telltale signs include:
- Earthy and/or musty odor
- Presence of moisture but not light
- Warping, peeling, or cracking of underlying material
In addition, if you apply chlorine bleach to a spot of mold, it will lighten. Mold will also continue to grow and spread, where a stain or smudge or dirt will not.
The presence of mold is not healthy for humans. Minor but irritating symptoms can include upper respiratory discomfort, wheezing, coughing, and itchy eyes or skin.
The Institute of Medicine has linked mold with upper respiratory symptoms in healthy people, and warns that it may be linked to hypersensitivity pneumonitis in people who are already at risk for that condition.
Other studies have suggested that there are serious risks for people who live in houses with mold. People with allergies, immune suppression, lung disease, or other respiratory disorders are at even more risk.
It’s important to make sure that the area around the sink is tightly sealed, and the best way to do that is with a high-quality caulk. Most experts recommend using silicone caulk in areas that will be exposed to water, such as around a kitchen sink, since the silicone caulk is water-resistant.
Silicone caulk is inorganic and it will not break down when exposed to extremes in temperatures, which is good if you are going to be using both hot and cold water in your sink (as most people do, obviously). It is elastic and adheres to most surfaces other than wood.
It is also very durable. Most good manufacturers warranty their silicone caulk for up to 20 years, so they fully expect it to last that long.
Caulking Around a Sink
When you’re ready to start caulking around your sink, you need to start with a clean surface. Remove any existing caulk with a utility knife, putty knife, or razor blade.
Remove paint, grease, dust, and dirt. Wipe the surface with rubbing alcohol or disinfectant on a clean, soft rag.
Rinse with clean water, pat dry, and allow to air dry. Tape around the area to ensure a clean line and to catch most of the excess caulk.
Apply the caulk carefully, preferably with a dripless caulk gun. Work from one end to the other, caulking in a continuous direction.
Fill the gaps around the sink with an even bead of caulk. Use steady pressure to keep the bead even and straight.
Seal the caulking with a caulk finishing tool, or with a fingertip moistened with warm soapy water. Remove the tape and wipe off as much excess caulk as you can before it dries.
Removing Excess Silicone Caulk: The First Step
If, as sometimes happens, the caulking process did not go as smoothly as you had hoped and you are left with silicone caulk inside your stainless steel sink, you’ll need to remove it. You’ll also want to do this without damaging the surface of the sink.
There are several ways that you can approach this; however, all of them start with removing as much of the unwanted caulk as possible. You can do this with a razor blade or a utility knife.
Work carefully so that you don’t cut yourself or scratch the surface of the sink. Remember that this is just the first step and you’ll remove the rest of the caulk later, so don’t risk injury to yourself or your sink by trying to get every last little bit.
Step Two with WD-40
WD-40, which stands for “Water Displacement, 40th Formula” is everybody’s favorite household hack. It was originally created in 1953 to protect the skin of the Atlas missile, but it’s served many other purposes through the years.
WD-40 was even inducted into the International Air & Space Hall of Fame at the San Diego Air & Space Museum.
Although it was never patented, the formula remains a trade secret. The MSDS data sheets indicate that it is composed of 45% to 50% low vapor pressure aliphatic hydrocarbon (isoparaffin), less than 35% petroleum base oil, less than 25% aliphatic hydrocarbons, and 2% to 3% carbon dioxide as a propellant.
Gas chromatography and mass spectrometry tests show that WD-40 is composed of C9 to C14 alkanes and mineral oil.
It has numerous uses around the house and elsewhere, some a fair bit less common than removing excess silicone caulk. A bus driver in Asia used WD-40 to remove a python that was coiled around the undercarriage of his bus, and police officers used WD-40 to free a naked burglar who had become stuck in an air conditioning vent.
Jim & Tim, The Duct Tape GuysTM claim that “You only need two tools in life, Duct Tape, and WD-40. If it’s not stuck and it’s supposed to be, Duct Tape it. If it’s stuck and it’s not supposed to be, WD-40it.”
So, when your silicone caulk is stuck to your sink and you don’t want it to be, WD-40 will help loosen and dissolve it so that you can peel it off. Apply the WD-40 liberally, let it soften the caulk, and then remove the caulk with the help of a utility knife or scraper.
WD-40 is many things, but it is not for human consumption. If you’re using it around your kitchen sink, you will need to scrub thoroughly to make sure that no trace of the compound remains.
Step Two with White Vinegar
When you’re applying the silicone caulk, you may observe that it has a familiar odor. It smells a bit like vinegar, and this is because it contains acetic acid.
This means that you can also use the acetic acid in white vinegar to soften any out-of-place silicone caulk so that you can remove it.
You can also use any other vinegar that you happen to have around the house; however, white vinegar has the highest concentration of acetic acid (other than spirit vinegar, which is not commonly found in household pantries). White vinegar is also significantly less expensive than other types of vinegar, so it is the ideal choice to use for this kind of project.
Apply the vinegar to the caulk and let it sit for five to ten minutes to soften up. Loosen a corner of the caulk with a razor blade or utility knife, and then try to peel the rest of the caulk away from the sink.
If it does not loosen at first, try applying a bit more vinegar and let it soften for another five to ten minutes. You can also scrape lightly with your blade, but be careful not to scratch the metal of your sink.
Once the silicone caulk has been removed, scrub with dish detergent on a sponge and rinse with plenty of clean water.
Step Two with Abrasive Cleanser
This method relies more on elbow grease and less on chemical solvents, which makes it more attractive if you are working in an area without adequate ventilation or you are concerned about using chemicals in an area where you also prepare food (although white vinegar is a food itself and is therefore perfectly safe to use in a kitchen).
Mix water with an abrasive cleanser to make a paste. Scrub the area with this paste on a nylon scrubber or bristle brush; do not use steel wool or a metal brush or you will likely damage the surface of your sink.
Rinse with clean water. If there is still some silicone remaining, repeat this process as necessary.
You may also want to do a scrub with an abrasive cleanser after removing most of the silicone with one of the chemical solvents. The abrasive scrub can remove small flecks that are difficult to peel off or lift with a utility knife.
Special Case: Black, Moldy Silicone Caulk
Silicone caulk is designed to be water-resistant, but it can still grow mold on itself if it is left damp in a dark area. As discussed above, mold is very dangerous to inhale and you do not want to be scrubbing or scraping it since that will release even more mold spores into the air.
If you need to remove moldy silicone caulk, first wash it down with soap and warm water.
Then prepare a solution of 3/4 cup chlorine bleach to one gallon of water. Thoroughly soak the moldy caulk with the bleach solution.
Let it sit for at least five minutes, which will kill the mold spores. Then remove the silicone caulk using the method of your choice.
I have a bachelor’s degree in construction engineering. When I’m not constructing or remodeling X-Ray Rooms, Cardiovascular Labs, and Pharmacies…I’m at home with my wife, two daughters and a dog. Outside of family, I love grilling and barbequing on my Big Green Egg and working on projects around the house.