Top 10 Best Silicone Adhesives for Undermount Sink

To hold an undermount sink in place without experiencing leaks, you will need a flexible and resilient adhesive. However, how well it holds an undermount sink depends on the materials involved. So, you need to choose the most effective adhesive to hold an undermount sink in place.

Silicone adhesive is best on the edges of the undermount sink to fix gaps between the countertop and the sink. When installing an undermount sink, one of the most important things to have is silicone adhesive.

Silicone sealants are helpful as they are resistant to mildew and mold while repelling moisture. To prevent water leaking, you must apply silicone caulk to the undermount kitchen sinks.

Best 100-percent Silicone Sealants for Undermount Kitchen and Bathroom Sink

Top Silicone Adhesives for Undermount Sink

Best Silicone for Undermount Sink Reviews:

Best Silicone for Undermount Sink

1. GE GE5040 Silicone II Undermount Kitchen Sink Sealant

GE GE5040 Silicone II Undermount Kitchen Sink Sealant

GE GE5040 Silicone II is packaged in an easy-to-hold tube that can squeeze without emitting the under-mount sink sealant. This caulk is made from 100% Silicone material.

It is 100% waterproof, making it suitable for areas with constant water exposure with no harm. It is specifically crafted for outdoor and indoor use with an array of uses around your home.

This kitchen sink sealant is crafted to meet ASTM C-920 expectations under class 35, making it suitable for almost all sink sealing tasks.

This clear silicone sealant is flexible with 40% more adaptability than Class 25 sealants in the Market. It has five times adhesive features compared to silicone one sink and bath sealants, which means it won’t leave any blemish on the expensive metals on the sinks

This sealant is favorable for quick fixes as it has a 30-minute ready formula that gives 10-year stress-free protection from mold and mildew. Despite having a clear color, you cannot paint it.

Highlighted Features:

  • The excellent adhesion ensures that it leaves no traces on the expensive metals on the sinks
  • It is perfect for quick fixes as it has a 30-minute ready formula with a 10-year cushion without mold and mildew.
  • 40% more adaptable compared to class 25 sealants
  • 5X sturdy adhesion
  • 100% waterproof and clear color
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2. Flex Shot Rubber Adhesive Sealant for Undermount Sink

Flex Shot Rubber Adhesive Caulk for Undermount Sink

Flex Shot is your perfect choice for a quick fix and efficient silicone for undermount sinks. You won’t need a caulking gun to place the sealant in a perfect place as it has a long nozzle.

This awesome silicone sink sealant is made from a solid rubber material, almond, and 8-oz that bonds, caulks, and seals every part of your house with water leakages.

This material makes it permanent, cannot crack or shrink, and is flexible; it can contract or expand to occupy enormous water leakage spaces.

When applied, it gives you up to 30 years of no cracks, fades, or deterioration. With a weight of 8 ounces and size of 1 by one by 1 inch, you can carry it around with ease.

This undermount kitchen sink sealant is available in clear, black, almond, and mold-resistant white. It is perfect for use in showers, toilets, bathroom windows, and tiles.

However, you can use it on other surfaces like decorative surfaces, art, and crafts to seal water leakage.

This kitchen sink silicone adhesive is recommended for the following surfaces; stone, porcelain, metal, paper, fiberglass, glass, tile, wood, granite, and other surfaces that have no grease or oil.

Highlighted Features:

  • Contracts and expands to fit in huge water cracks
  • It gives a 30-year assurance of no-fade cracks or deterioration in color.
  • you can use it on almost all surfaces that have no grease or oil
  • You won’t need a caulking gun; It has a prolonged nozzle for perfect placement.
  • It creates a watertight and adaptable blockade that can be used after a few minutes of applying.
  • Bonds, seals, and caulks almost every water leakage route.
  • Caulks, bonds, and seals virtually everything.
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3. DAP 18001 6Oz Kwik 100% Silicone Sealant for Undermount Sink

DAP 18001 6Oz Kwik 100% Silicone Sealant for Undermount Sink

Kwik silicone sealant comes with a small tube weighing 8 ounces that you can carry around.

This undermount sink caulk mold is adhesive to attach the sink to the wall and caulk water leakage points in your home. The acrylic latex material makes it bonds like glue and seal like a caulk.

Despite being one of the best glue for undermount sinks, it works at a specific temperature range of 100 degrees and 40 degrees.

The temperature range means that You can only use it indoors. You can use your bathroom sink or tub after 10 minutes of applying this undermount sink caulk.

It comes with a flexible tube to squeeze the white latex material that is 100% waterproof to cover water loopholes efficiently. It has a perfect size 10.1 FL OZ of 10 by three by 2 inches that fit your palm perfectly for squeezing it.

It also has an additional sodium component that adds extra adhesion and makes it easier to clean. To prevent it from drying up in the jar, restore the lid perfectly.

To clean the caps, wipe off the wet sealant using a dry cloth then Isopropyl alcohol to clean.

Highlighted Features:

  • 100% watertight seal and is ready to use after 10 minutes of applying.
  • The latex material makes it paintable and produces a low odor
  • Spread Caulk is mildew and mold resistant.
  • Most efficient for indoor use
  • Ten by three by 2 inches in size
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4. Red Devil StormGuard RTV Kitchen Sink Sealant

Red Devil StormGuard RTV Kitchen Sink Silicone Sealant

StormGuard RTV is made from 100% silicone material and begins to cure immediately after exposure to the air.

After the rigorous test of endurance and quality, Red Devil dropped another high-ranking silicone sealant.

The quick-drying element makes it one of the finest silicones for undermount sinks. It becomes rain-resistant after 30 minutes of applying it.

It gives intact adhesion, durability, and flexibility, making it favorable for many surfaces indoors and outdoors.

One of the most distinctive elements is its versatility, as you can use it on both dry and wet surfaces—this versatility and durability give a lifetime guarantee free of mildew and mold. The undermount sink sealant does not turn yellow over time.

This clear silicone sealant for the sink has a product tube of 2.8 oz of 2.13 by 1.38 by 7.75 inches, perfectly fitting your palms. It weighs a paltry 3.2 ounces.

When applied, it does not crack or shrink due to its advanced adhesive and flexibility.

Before applying, the surface must be clean with no dirt, old glue, grease, or oil. To apply this adhesive to attach the sink to the wall, you will push the bead over the nozzle and then squeeze the tube gently.

Highlighted Features:

  • Advanced adaptability and adhesion for a long-lasting experience
  • It dries up after being exposed to moisture
  • You can use it on dry or wet surfaces
  • It does not crack or shrink after applying it
  • Dimension of 7.75 by 2.13 by 1.38 inches
  • Rain resistant after 30 minutes
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5. Gorilla 2.8 Ounce Squeeze Tube Clear Silicone Adhesive

Gorilla 2.8 Ounce Squeeze Tube Clear Silicone Adhesive

This silicone adhesive from Gorilla is made of 100% silicone material that makes it sturdy and durable.

You can use this kitchen sink sealant on other surfaces like windows, bathtubs, gutters, plumbing, marine, doors, and many others. After 30 minutes of applying, it becomes rain–resistant but takes up to 24 hours to fully cure.

After which, it can be exposed to moisture, water, and other condition without breaking. Gorilla, a clear silicone sealant for the undermount sink, goes for a long time without changing color, shrinking, or cracking.

This silicone sealant works perfectly in temperatures over 40 degrees Fahrenheit. The 2.8 oz squeeze tube measures 3.68 ounces, quite light measuring 7.63 by 3.75 by 1.41 inches.

Before applying the silicone for undermount sink installation, ensure that the surface is clean and has no grease, old sealant, or oil traces. The most favorable conditions are above 40F.

Chop to the required bead size, then squeeze the sealant out of the nozzle to form a layer of the adhesive sealant on the surface.

Before storing it, ensure that it is cleaned with a dry cloth or isopropyl solution according to the manufacturer’s instructions.

Highlighted Features:

  • It works perfectly for temperatures above 40F.
  • Dries 30 minutes after application and cures fully after 24 hours.
  • Weighs 3.68 ounces.
  • 100% adhesive silicone sealant that changes to clear after being dry.
  • Dimensions of 7.63 by 3.75 by 1.41 inches.
  • Strongest silicone adhesive for windows, bath, kitchen, auto, gutters, marine, and other water-leaking surfaces.
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6. GE GE012A 12 Pack All Purpose 100% Silicone Sealant Caulk

GE GE012A 12 Pack All Purpose 100% Silicone Sealant Caulk

GE GE012A is a long-lasting undermount sink caulk from Momentive Performance Materials. It is made from 100% silicone material. The silicone material combines with acetic acid to act as a curing agent; this is why it smells like vinegar.

The silicone material makes it resistant to water, mildew, moisture, and many other solvents. It dries to clear after 30 minutes but cures fully after at least 24 hours.

You can use this kitchen and bath caulk in other areas like windows, pipes, wires, basement, trims, baseboards, and molding.

GE GE012A becomes rain-resistant on the day of application and gives you seven years of comfort without mildew or mold growth; and is used on vinyl siding, plasters, plastic, metal, and most wood effectively. You can use it indoors and outdoors cannot be painted.

This undermount sink caulk paste comes in a 10.1 oz tube weighing 9 pounds and dimensions of 6.06 by 8.03 by 11.65 inches making it perfect for your arms.

It gives a long-lasting adhesive surface that does not discolor.

Highlighted Features:

  • Made from 100% silicone material
  • Weighs 9 pounds
  • Dimension of 6.06 by 8.03 by 11.65 inches
  • It dries after 30 minutes and cures fully after 24 hours
  • It can be sued indoors and outdoors
  • Adhesive to most wood, metal, glass, and other surfaces without oil and grease

7. Mitreapel Aquarium Non Toxic 100% Silicone Adhesive

Aquarium Non Toxic 100% Silicone Adhesive

This silicone caulk for undermount sink, a product of Apel, is made from 100% silicone. It contains no fungicides or additives that can be harmful to the fish or any useful bacteria found in the sea.

You can use aquarium silicone adhesive sealant for different purposes in your aquarium. You can use this clear undermount sink caulk to seal leaks, seams, and attach decorations on the sides and the lower parts of your aquarium.

This glue for undermount sinks is flexible and strong, forming a long-lasting seal that cannot stoop to shrinking or cracks. The bonded items hold together the aquarium safely.

Usually, aquarium glues take much longer to dry and cure, but this glue dries faster. After a successful application, it takes between 1 to 2 hours to dry and up to 24 hours to cure fully. The packaging bottle measures 4.09 by 9.17 by 2.17 inches weighing 1.68 pounds, making it perfect for your palms.

When cleaning it up, wipe off the remnant product using a dry cloth. You can opt to use an isopropyl solution, but after checking the manufacturer’s direction. After cleaning, close the lid tightly, then store it in a cool, dry place.

Highlights Features:

  • The 100% adhesive silicone sealant is non-toxic and cannot harm your fish
  • It dries after between 1 and two hours and takes up to 24 hours to fully cure.
  • It is flexible and durable
  • Weighs 1.68 pounds

8. Red Devil Duraguard Kitchen & Bath Undermount Sink Caulk

Red Devil Duraguard Kitchen & Bath Undermount Sink Caulk

Duraguard is another durable material from the wax giants, Red Devil. This kitchen sink silicone adhesive was passed through rigorous tests to withstand harsh weather without deteriorating or turning yellow.

The airtight silicone adhesive Caulk was derived from a high-tech formula to make it flexible and long-lasting.

The perfect adhesion brings about a protective coating against moisture or mildew, making it one of the durable silicones for undermount sinks.

You can use the odorless formula derived from silicone on fixtures, sinks, showers, and tubs and cures to bring about a silk and satin finish.

Usually, when applied, it is a clear substance but will change for a while after some time but reverts to the clear color after a week or so. When dry, you can paint it to any suitable without causing any leakages.

Before replacing the cap, ensure that you wipe off the remaining wet sealant on the cap. Make sure you store them in a dry, cool place. 

Highlighted Features:

  • Provides a watertight and durable seal on the water-leaking surfaces
  • You can use this silicone adhesive for the undermount sink on various surfaces in the bathroom and kitchen.
  • The odorless product can be painted to any color without fear.
  • When applied, it is white but turns white before reverting to clear when dry.
  • It can be applied above and below water effectively
  • It is durable

9. STAR BRITE White Silicone Sealant for Stainless Steel Undermount Kitchen Sink

STAR BRITE White Silicone Sealant for Stainless Steel Undermount Kitchen Sink

Marine sealant is derived from 100% marine 2.8 oz graded silicone. Star Brite, the proprietor of this silicone sealant, is a leader in marine wax manufacturing. It designed a world-class silicone sealant that passed through multiple tests to match heavy industrial use.

This sensational silicone adhesive provides a waterproof and durable seal for stainless steel, fiberglass, metal, glass, wood, and selected plastics on your undermount sink perfectly.

This sealant gives a waterproof and durable seal that does not turn yellow, crack or shrink. The marine material makes it easy to apply the loopholes and remove them when the need arises.

It can fall victim to solvents, sunlight, weathering, or any chemicals after applying it. This silicone for sink installation can be applied above or underwater but is ideal for installing deck hardware.

When applied, it dries tack-free in one hour and cures perfectly in 24 hours whether it was applied underwater or above water as a gasket product under compression.

This silicone is applied in places where adhesive or water-resistant caulk sealant is required, especially in sinks, bathtubs, windows, gutters, trim, or doors.

It comes in a small tube of 0.7 ounces and a small dimension of 4.5 by 1.5 by 8 inches, making it efficient when carrying around.

Highlighted Features:

  • It can be used in glass, plastic, ceramic tile, and plastic surfaces perfectly.
  • Marine-quality material that is used can use above or in the water perfectly.
  • Dries without tack in one hour or less and cures perfectly in 24 hours
  • Designed and passed through rigorous tests to fit the minimal environmental requirements and fine quality
  • Provides an airtight and waterproof bond that can be easily mounted and removed
  • It cannot be affected by weathering, sunlight, solvents, or any chemicals

10. Loctite Marine Epoxy White Silicone for Undermount Sink

Loctite Marine Epoxy White Silicone for Undermount Sink

Loctite Marine Epoxy is versatile as it can use underwater and above water. This silicone for underwater sinks cures after approximately 50 minutes of applying it to your water leaking spots.

You can use it on galvanized pipes, metal, brass pipes, glass, copper pipes, ceramic, PVC pipes, tile, and plastic without shrinking or expanding.

Loctite has a vast experience of 50 years, providing its client with high-quality sealing and adhesive solutions. This kitchen sink sealant is resistant to moisture, impacts, or solvents. It comes with a reliable syringe to draw small portions on the affected parts conveniently.

The distinctive 2-section routine is perfect for jobs that need strong adhesive strength on the platforms that are exposed to water. You can apply this kitchen and bath caulk underwater, and it will cure you with no worries.

Loctite Marine Epoxy is used as a permanent silicone for sink installation on wood, metal, glass, or any sink material that is not exposed to oil or grease.

It creates a strong adhesive platform that is water and solvent resistant and can be drilled without cracking. It comes in a small and portable tube of ‎1.38 x 3.88 x 8 inches. Overall, it is a high-quality adhesive for undermount sink to granite.

Highlighted Features:

  • It is a one-time application that lasts longer and does not shrink.
  • Highly durable, solvent, and water-resistant.
  • It can be applied underwater and cured without leaking any water
  • Has a syringe to draw and apply the right portions to the affected part.
  • Durable; cannot crack when subjected to drilling.
  • Applied to wood, metal, glass, or any other sink component with no oil or grease.

Best Silicone Sealant for Undermount Kitchen Sink Buying Guide

Before you go shopping for silicone adhesives for the undermount sink, you need to know what to consider.


In your bathroom or kitchen, you need to seal cracks or holes from exposure to water. In that regard, you need to purchase glue to hold undermount sinks that protects your kitchen surface and bathroom from damage by water.

At that point, you need to check whether the sealant is waterproof. Check on the features or the package if the adhesive is certified as being water-resistant. If that’s the case, the glue will perform the best work when installing an undermount sink.

Mold and Mildew Protection

Check whether the sealant protects against mold and mildew. Is it? If so, continue reading when a silicone adhesive has the mold and mildew resistance feature. Then, you are purchasing the right product.

First, this is because the silicone will last for years without being affected by mold or mildew. Also, these two are enemies of silicone sealants.

Thus, with one that has mold and mildew protection, you are sure of the best product for your undermount sink installation.


Another thing to consider is the color. And this is vital to the place you are applying the silicone sealant. If it is outdoor and your wall is bright, it is better to use a clear or white adhesive. Suppose the surface is dark or in a hidden area. It is best to consider a black sealant.

For example, the Flex Shot Rubber adhesive sealant has four colors. So, depending on your preference, you can either choose white, almond, clear, or black.

However, those are not the only available colors in the market. You can also get a gold silicone sealant.

Before selecting the color of the silicone sealant, consider the color with your requirements and the area of application.

Type of Caulk

Currently, you can either find a silicone caulk that is made of pure silicone or latex. According to our experts, it is best to choose a pure silicone caulk. Also, in this review, most of the products are made with pure silicone.

This is because pure 100% silicone is suitable for installing an undermount sink. Therefore, be very keen on the type of caulk you are going to purchase. But as for installing undermount sinks, always choose a sealant that is 100% made of silicone.


Check if the sealant is flexible in both cold and hot temperatures. Is it according to the manufacturer’s features? That’s for you to answer.

A flexible silicone sealant should be flexible to allow expansion and contraction during varying temperatures.

This ensures that it doesn’t leave openings for water to get onto the bathroom walls or surface of the kitchen sink. On that note, make sure that the adhesive you choose is flexible at all temperatures.


How many times have you been under your sink? I doubt if it is frequent and, in that case, the leakage might be happening without your knowledge. This will be due to a poor silicone sealant used during installation.

Is Silicone Adhesive Enough to Hold an Undermount Sink

Is Silicone Strong Enough to Hold an Undermount Sink?

Attaching the Undermount sink with silicone caulk is very common. Silicone is a very powerful adhesive and can hold your sink in place when used in combination with epoxy.

However, for durability, you should use corner clips or mechanical support as anchors to help keep it steady.

Which Silicone for Undermount Sink?

Silicone bonds better than most adhesives and is thus great for sealing an undermount sink. The standard silicone adhesive is 100% pure silicone sealant.

This grade of single-component silicone is great for the job because it binds to everything. A good example of a 100% pure silicone is the Gorilla Clear Silicone Sealant Caulk.

Is 100% Silicone an Adhesive?

Yes, 100% silicone is an adhesive sealant, and a good one at that. It can serve multiple purposes including sealing, binding, and caulking.

Therefore, most manufacturers recommend it for the installation of undermount sinks. Its resilience and flexibility make it good for binding surfaces together.  

How Strong is Silicone Adhesive?

The Silicone Adhesive has a very high tensile strength of 7.75 MPa. It can also withstand extremely high temperatures up to 600° F or 315° C.

Silicone adhesive is water, age, vibration, and shock-resistant. The Undermount sink adhesive is in the form of a gel but cures to become a strong, durable silicone rubber.

What Adhesive is Suitable for Undermount Sink?

The installation of an undermount kitchen sink requires perfection for the sink to be enjoyed. To install the sink, you will need certain tools, the most important of which is the Undermount sink adhesive.

Silicone adhesive fits nicely and just a tube will do. Specifically, clear and translucent silicone gives the best bond.

What is the Best Adhesive for Undermount Sink to Granite?

When installing a sink on granite, the outcome is as lasting as the strength of the adhesive used. To get a proper hold and a long-lasting attachment, you should use a clear 100% silicone Undermount sink adhesive.

Granite retailers warn against using construction adhesives. So, you should opt for a silicone advanced adhesive for granite countertops. 

Can You Use Silicone Caulk on Granite?

Although granite doesn’t absorb water, caulking undermount kitchen sink is a necessity as it’s susceptible to leaks. However, like latex caulk, not all caulk materials have a firm hold on granite.

But luckily, silicone caulk is perfect for granite as it is strong and durable. For a granite countertop, silicone ASTM C920 or Loctite is your best bet.

What is the Best Adhesive for Undermount Kitchen Sink?

If you want to install an undermount sink on a counterto, there are several adhesives for this on the market. However, to get the best result, manufacturers recommend 100% silicone adhesive that is water-resistant.

This Undermount sink adhesive will give the best bond to most types of materials when applied properly thus preventing leakage.

Types of Undermount Sink Glues

To fix or install an Undermount sink, you need glue. While there are various types of glues in the market, only specific adhesives are suitable and efficient. For caulking undermount kitchen sink, you need a water repellent adhesive.

Not all are strong enough to deal, bond, and support the weight of the sink all at once. So, an adhesive for undermount sink should be able to deliver maximum bind and support. 

There are two major types of Undermount sink glue which are:

  • Silicone adhesive or silicone caulking, and
  • Epoxy adhesive

Both are favorable for installing Undermount sinks because they are strong and water repellent. Also, they have high resistance to moisture, humidity, and dampness. Silicone especially bonds well to most countertop materials.

Thus,  both types of glue are used to secure undermount sinks. To do this, you will first apply a two-part epoxy adhesive (resin and hardener). Next, you apply your silicone caulk around the perimeters to seal it up. 

Is Epoxy Strong Enough to Hold Undermount Sink?

The two-part epoxy (resin and hardener) is a good filler. It dries off fast, requiring only 30 minutes. It’s strong, cohesive, and can resist moisture thus filling microscopic holes and creating a strong attachment.

However, though it is used as an undermount sink adhesive, it cannot hold if used alone. 

Does Silicone Hold Sink in Place?

The function of the silicone adhesive or caulk is to seal the sink as a preventive measure against leakage. Though it binds the undermount sink to the countertop, you can’t rely on it to keep your sink in place when wet.

The mechanical fasteners in the form of metal clips are the actual anchors that hold the sink in place. 

How to Attach Undermount Sink to Slab Using Silicone?

Attaching an undermount sink to a slab using silicone is an easy task you can perform. I’ll give you an easy DIY step-by-step guide to follow. 

However, you’re going to need acetone, a caulk gun, rags, clear or translucent silicone, two-part epoxy, 2 bar clamps, cardboard, and a wooden slab. So, here are the steps to do it.

Step 1: Selecting Your Sink

The first step is pretty easy. It entails you selecting a sink that suits your taste before the slab is cut to avoid a mismatch. When you select a sink, take note of its specs and inform your stone fabricator. 

By doing so, you will get the perfect slab for your undermount sink. With a perfect pre-cut stone slab that fits your undermount sink, the installation will be easier for you.

Step 2: Get Your Tools in Place and Get Cleaning

Before you proceed, you’ve got to have all the tools listed above. Keep them close by and begin your task. You have to clean the top and underside of the sink and slab to remove dust and dirt. 

So, apply acetone to your rag and clean. Then, go over it with a neat, dry rag. When cleaning, focus on the perimeters where you will apply glue, or else your sink will not stick. 

Step 3: Prepare to Install

Fill up your caulk gun and apply a sizable bead of silicone undermount sink adhesive around the sink’s perimeters. If the silicone is too thin it won’t hold and if it’s too much it will spill over. So, go with a moderate amount. 

Step 4: Install and Position Your Sink

Place two sheets of cardboard on the cut edges of the slab to avoid scratches. Place a wooden board across the opening in the slab so it sits on the cardboard.

Next, place a clamp inside the sink. Proceed to gently lift up the sink and clamp it securely onto the wooden board. 

Step 5: Time for Adjustments

Having clamped the sink, examine and adjust it where necessary. You should ensure that the overhang lies evenly on all sides. 

Step 6: Time to Clean Again

Once it is properly straightened, the excess glue will ooze over the sides so you clean it up while it’s wet. Dip your finger in acetone and give it a firm wipe to ensure it’s smooth.

Step 7: Final Touch

Leave it for 24 hours to cure. Check the instructions on the adhesive because some take a longer time to dry. When it’s dry, flip it over and test the strength. Finally, it’s set for use.

What to Consider When Using an Undermount Sink Adhesive?

Normally, installation using the regular silicone undermount sink adhesive takes a professional about 30 minutes. However, there are new MS polymer adhesives available in the market claiming faster installation. 

Though they’re good, they aren’t always reliable for holding undermount sinks because of the weight. So, here are factors to consider when choosing an undermount sink adhesive.

1. Curing

MS polymers don’t cure in seconds as they claim. Curing begins from the outside and goes in so the outside may be dry while the inside is still wet. This misconception may mislead and prevent you from attaining 100% bonding strength. 

2. Sink Positioning 

The outer layer of silicone takes a longer time to cure in comparison to MS polymer. Therefore, you have enough time to properly position your sink using silicone.

3. Resistance to Mildew and Mold 

Silicone adhesives specifically for kitchen and bathroom use. Therefore, have fungicides that protect the seal from mold and mildew for three years. On the contrary, MS polymers are industrial adhesives that have been repurposed. So, they lack fungicides.

4. Replacement 

Changing an undermount sink is easier as you just cut the silicone and remove the fasteners. Anundermount MA polymer is harder to remove and could lead to cracks on your cabinet or countertop. 

Can You Just Glue an Undermount Kitchen Sink?

Securing a sink to a countertop with glue alone isn’t enough to hold a functional Undermount sink. When the weight of water and dishes are added, the sink is likely to crash having been held by just glue. So, you either use a combination of glue and two-part epoxy or glue and sink clips

What Kind of Glue to Hold A Sink in a Vanity?

A bathroom vanity sink can be held by a silicone caulking seal. This caulking glue is strong, waterproof, and watertight, so it seals the sink and prevents infiltration of water. With all these properties, it prevents your countertop from experiencing rot. 

What Will Silicone not Stick to?

Silicone only sticks to the adhesive system or Pressure Sensitive Adhesive. Therefore, it depends on the pressure applied to the stick but even at the same pressure, some materials are more stackable. The reason is that the surface energy of some materials is lower than others. Hence, the difference.  

What is the Difference Between Silicone Sealant and Silicone Adhesive?

Although silicone sealant and adhesive are similar and used interchangeably, they are not the same. The difference lies in the quantity of filler present.

Sealants contain fillers like cellulose and chalk which reduce the adhesive properties of silicone. On the other hand, silicone adhesive contains a single compound which is 100% clear silicone.

Also, a sealant is wet and needs to cure before achieving its aim, while adhesive is viscoelastic and doesn’t cure. Hence, a cured silicone rubber will require an adhesive to stick to any substrate. Finally, a silicone sealant is watertight and airtight, while a silicone adhesive binds. 

How Long Will Silicone Last?

The shelf life of silicone while still in its container is one year. However, when applied, silicone sealant or adhesive lasts way longer. The minimum time frame for which silicone is effective is 20 years.

For this period, it remains binding, watertight, and airtight. However, when its strength begins to weaken, you can always reapply it.

How Long Should Silicone Dry Before Adding Water?

Normally, silicone sealant takes 24 hours to dry completely, after which it can resist water, moisture, and dampness. However, if it has a very high degree of consistency, it may take longer to dry. If it comes into contact with wetness before drying, it may take longer to cure or the seal may be weak. 

How Thick Should Silicone Sealant be?

Silicone sealants are liquid and have a gel-like consistency but cure to develop a rubber texture. 

To secure an Undermount sink with silicone sealant, a like or bead of caulk should be more than ¼“. Silicone sealant shrinks as it dries up therefore, anything thinner than ¼” will be too thin to create a proper seal. 

How to Smooth Silicone Sealant?

In order to get a neat finish, it is necessary to smoothen your silicone sealant after application. To smoothen and secure an Undermount sink with silicone sealant, you will need either alcohol or spirit.

If you’re using alcohol, transfer it into a spray bottle and spray it onto the caulking bead. Then, run your finger over it before the alcohol evaporates to smoothen the silicone sealant.

When using spirit, dip your finger into spirit to prevent the silicone from sticking to you. Then, run your finger over the bead of caulk with stable pressure. These methods will give you a neat, smooth finish.

How to Reseal an Undermount Sink Using Silicone Sealant

Though the process is cumbersome, you can likely remedy leaks on an undermount sink by yourself.

Start by crawling under the sink and checking to ensure the clamps are securely holding the sink to the bottom of the countertop.

Apply silicone sealant to the seam around the sink from inside the cabinet. If you make sure the sink is tightly clamped, you can try to recaulk and assess if it has eliminated any leaking. 

The best solution is entirely to remove the sink and re-seal the sink to the countertop.

Step 1: Shut off the water.

Step 2: Remove all of the plumbing supply and drain pipes.

Step 3: Unclamp the under-mount sink from the countertop.

Step 4: If the silicone caulk is old enough and fails, it should be relatively easy to pull the sink away from the countertop.

Step 5: With the sink removed, scrape away as much caulk from the top flange of the sink.

Step 6: Clean the surfaces thoroughly with denatured alcohol.

Step 7: With the joint clean and dry, apply a thin bead of the recommended silicone sealant to the top flange of the sink.

Step 8: Re-install the sink quickly before the silicone sealant cures.

Step 9: Clamp into place.

Step 10: With a clean rag, wipe away any sealant that may have sealed through either side of the sink.

Caulk Vs Silicone – The Difference

What is Caulk?

Every house has gaps and cracks through which outdoor air enters and indoor air escapes. Caulk is a sealing agent used to prevent the passage of water and air into joints or openings in your house. Caulking keeps the water from passing through the joints.

A caulking gun is mainly used to apply caulking on surfaces that need waterproof. The gun is loaded with a cartridge of a toothpaste-like caulking compound which you can squeeze out after you press the trigger.

You can apply the paste carefully between the surfaces.

What is Silicone?

Silicone is the best caulk for undermount kitchen sinks used in areas prone to expansion and contraction. It acts as a barrier to prevent air and water passage, primarily for bath seals and between the tiles.

Unlike caulk, you cannot paint over silicone-based sealants. Silicone sealants have excellent joint movement capabilities, and they are more flexible so that they can be applied on almost any surface you want, both indoors and outdoors.


1. How Long Does Silicone Take to Dry?

Silicone adhesive sealant is versatile, but, unlike other adhesives, it must cure. Curing means letting it dry, and although it is not necessarily a complicated process, it takes patience.

Silicone adhesives can take as little as 24 hours to cure, but it may also take up to several days if the sealant is thick. So, this depends on the silicone sealant you buy.

2. Can I Use a Grease Gun to Caulk a Sink?

A grease gun is used to apply grease or lubricant. The primary purpose of a grease gun is to lubricate moving parts, to give them a smooth, slippery surface. Grease guns may be hand-powered or electric-powered. The use of a caulking gun is to apply caulk for sealing fixtures mainly.

An electric caulk gun offers many advantages. For instance, power caulk guns help better regulate how much caulk is released by featuring variable speeds. Since caulk may come in several viscosities,

3. Is Silicone Enough to Hold an Undermount Sink?

Most undermount sink manufacturers recommend that you use pure, 100% silicone sealant for undermount sink installation.

Silicone sealants are designed for resilient flexibility and have good adhesive properties. If you use an ordinary caulk to seal the sink, it likely will fail quickly.

4. How Many Tubes of Caulk do I Need for the Kitchen Sink?

The tube of caulk will fill based on the joint width and depth. 1–9 FL. OZ. cartridge covers approximately 56 linear feet at a 3⁄16″ bead size.

Final Words

I have reviewed each silicone sealant appropriately and covered all its key features. Therefore, as you install an undermount sink in your house, make sure to buy the right silicone sealant. This is because it will prevent mold formation due to water leakage on the sides of the sink.

So, with a variety of brands to choose from, it can be challenging. Based on these top 10 silicones for undermount kitchen sink review, the overall best silicone adhesive is GE GE5040 Silicone II kitchen sealant.

This is because it has valuable features and it will ensure you fix your undermount kitchen sink to almost any countertop within a short time. Additionally, it is 100% waterproof, and 40% more adaptable than other silicone sealants.

Though there are numerous types of glues, the best is 100% clear silicone adhesive/ sealant. It binds the sink to the countertop and seals the perimeters leaving no space for leakage, due or moisture.

Lisa Burks

Hi, I'm Lisa Burks, founder of the Sink Formula blog, and plumber of 5 years experience.

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