How to Fix A Cracked Granite Sink

A granite sink makes your kitchen unique by being the same color as the countertop and adds a flowing elegance to the space that you spend so much time in. And they are much more durable than stainless steel or porcelain, too!

But in time, they can also develop cracks. It could be because cracks appeared in the installation itself and became waterlogged. Or maybe someone dropped something sharp and heavy and chipped a part of it.

Small cracks could later become wide-open ones, which is why it is of utmost importance to fix them before the problem becomes worse.

Fortunately, there is an easy method to fix a cracked granite sink.

But first,

Are All Granite Sinks 100% Granite?

The answer to that will be NO. The more affordable version of granite sinks is made up of 70-80% granite dust mixed with acrylic resin.

Or it could even be quartz dust and acrylic resin. Both these types of sinks are called granite composite sinks.

See how to distinguish between composite sinks and natural granite sinks:

If you were told that your granite sink did not need to be sealed against stains upon installation, or was bought at an economical price, or has a uniform color throughout its body, then you probably have a granite composite sink.

Don’t worry, granite composite sinks are just as sturdy as natural granite sinks, and the only notable difference between them in use is the color.

There is a greater selection of colors in composite granite, and the color is more uniformly distributed along its body, too.

And when you think that you get all the actual benefits of natural stone on your composite sink for a fraction of its price, the trade-in doesn’t seem so bad after all.

5 Steps to Fix a Cracked Granite Sink:

No worries there. Whether natural or granite composite, the method for fixing its cracks will remain the same. But do see the Bonus step to see how you should care for a composite sink after fixing its cracks.

Materials Required:

  • Epoxy filler of a color that merges with your sink
  • Plastic spatula
  • Cleaning materials such as cloth, sponge, and scouring powder
  • Newspapers and tape
  • Warm and cold water
  • Protective gloves and goggles
  • 400-grit sandpaper to 3000-grit sandpaper
  • Buffing wheels with wet and dry pads

Step 1- Start by Cleaning the Sink

Pour the scouring powder inside the sink and wet the cloth with warm water. Gently scrub the sink, thoroughly cleaning every inch.

With that, surface scratches will be removed, along with any grime and grit or water spots there were.

Rinse and wipe the sink with a dry cloth, and look for scratches apart from the cracks.

If there are scratches, use the 400-grit sandpaper and scrub thoroughly to smoothen them out.

Rinse the sink again and wipe it clean. Let it dry completely before proceeding to Step 2.

Step 2- Next, Prep the Sink

The cracks in the granite surface would be clearly visible once Step 1 is done. Examine them.

Take out the newspaper and fix them with the tape, flush along the sides of the cracks.

We are going to fill the cracks with epoxy in Step 4, and we don’t want the material to get into the rest of the granite surface.

Step 3- Mixing the Epoxy

(Wear gloves and goggles for this!)

Epoxy resins are adhesives, and generally, there will be two parts to this material- a filler and a hardener.

Every epoxy might have differences from one another in terms of how to be mixed. Therefore, follow the instructions on the cover of the epoxy that you bought.

Generally, though, this is how you do it:

  • Open the filler and take out a small amount using a mixing stick.
  • Put that amount in a paper cup that is going to hold the epoxy for your use. 
  • Open the hardener and take out a little amount–the ratio is 30 parts of filler to 1 part of hardener.

You may also note the use of a tint to get the epoxy as near to your sink’s color as possible. The tint is to be added after the hardener.

Note that the epoxy is going to harden in under two minutes once the hardener is added, so mix as much as is necessary for each of the cracks and use separately.

Once it is mixed, you can proceed to Step 4. 

Step 4- Finally, Filling the Cracks With Epoxy

If you have large cracks in your granite sink, pour the epoxy into it. Using the plastic spatula, push the epoxy in the crack and even it out.

Once the epoxy is on a level with the rest of the sink surface, make sure that it does not spillover. You can do this by wiping the spatula on the edges of the cracks so that none of the resin material spills out.

For smaller cracks, use the spatula to apply and spread the epoxy so that the cracks are on level with the rest of the sink surface.

Now that you have filled all the cracks with epoxy, you can remove the newspaper and wipe away any excess material still outside the cracks.

Wait for the epoxy to cure. Depending on the size of the cracks, this may take up to 24 hours or several days. Consult the epoxy package to see how many hours it needs to set.

Wait at least 2 days before using the sink, lest all your hard work is in vain.

Step 5 (Optional): Polishing Your Granite Sink

Even if the epoxy is the color of your sink, sometimes it may show separate from your sink. You may not have acquired the good-as-new look that you so desired.

For that, let’s polish the granite!

This is to be done after the epoxy has set completely and you are almost ready to use the sink.

Steps to follow for natural granite sink:

  • Using mild dishwashing soap and sponger, thoroughly clean the excess epoxy or any other material that should not be on your sink surface, taking care not to pry open the cracks themselves. 
  • Using first the wet pads of the buffing wheel, polish the repaired area. 
  • Then use the dry pads to do the same. 
  • Starting with the 400-grit, work up to the 3000-grit sandpaper and polish the area.

For a composite sink, you have to apply a sealer to prevent water staining. Consult a professional for this.

Once you have begun using the sink, you can use mild dishwashing soap to clean the sink every day and add a coat of cooking oil to keep its shine.

Read our complete guide about how to install a granite sink.

Wrap Up

See how easy it was to fix your granite sink? You don’t need to throw away something just because it has developed some issues.

For granite sinks, the cracks are the biggest issue, apart from stains. And both can be easily fixed, and you can do it yourself!

But wipe down the sink every day with mild soap and a sponge, and do not let water pool in the cracks if they develop at all. A little care goes a long way, doesn’t it?

We hope that once you have repaired your sink, it will remain wholesome for very long too, as ours did!

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