How to Make a Mosaic Coaster

Coasters are common household items that are used to protect furniture from scratches or glass rings, and you can add a decorative touch to your coasters by giving them a mosaic effect. Mosaic is the art of decorating with small and uneven pieces of coloured glass, stone, tiles, or other material.

Mosaic was used during ancient times for decorative purposes to evoke cultural significance in major buildings or landmarks such as churches and cathedrals. Today, mosaic is still used by people to add a decorative touch their walls, windows, furniture, or artwork.

Measure two ounces of plaster into a disposable container using a measuring spoon or other measuring device. Add one ounce of warm water and stir the mixture until it takes a smooth, batter-like texture.

Pour the mixture into a reusable coaster mould. Tap the mould lightly around the edges to flatten out any air bubbles in the mixture.

Allow the plaster to dry in the mould for about an hour or an hour and a half. Touch the mould to make sure it has dried.

Remove the plaster by turning the mould over and gently pop the plaster piece out of place.

Repeat the previous four steps four times to make four coasters, or repeat as desired to make as many coasters as you want.

Place the plaster on a paper towel and place it in the microwave. Set the microwave on the low or defrost setting for two minutes. Allow the plaster to cool for one minute.

Repeat the previous microwave step another two times. The coaster should be heated and cooled three times in total.

Break coloured tiles by placing them between layers of newspaper on hard surface and hit them hard with a hammer.

Brush a thick layer of adhesive on the top surface of the coaster.

Stick each tile chip into the adhesive, placing one beside another and leaving a small space between each one. The tile pieces are not supposed to fit perfectly beside each other, which creates the mosaic effect.

Apply tiles to the adhesive until the entire surface of the coaster has been covered. Allow the coaster to dry for 12 minutes to 24 minutes.

Put on the latex gloves and empty the mosaic grout into a container. Measure two ounces of water and mix it into the grout. Stir until you get a thick consistency that resembles oatmeal.

Apply the grout using a plastic spoon over the entire surface and between all the cracks of each tile piece. Use your fingertips to push the grout between the cracks. Allow the grout to set for 10 to 15 minutes.

Fill a bowl with water and use a sponge to soak up some water and scrub the surface of the coaster to clean away the excess grout. You should see coloured tiles show through and the cracks will all be filled in.

Wipe the coaster with a clean, dry towel to remove any leftover residue.


When using the microwave, do not use a medium or high setting. Do not microwave the plastic coaster mould since this could cause damage to your microwave and your coaster.

Things You'll Need

  • Plaster
  • Tile chips
  • Reusable coaster mould
  • Mosaic grout
  • Adhesive
  • Brush
  • Latex gloves
  • Sponge
  • Container
  • Bowl
  • Measuring spoon
  • Paper towel
  • Microwave
  • Hammer
  • Newspaper
  • Towel
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About the Author

Elise Stall is an experienced writer, blogger and online entrepreneur who has been writing professionally since 2009. She currently blogs at Elise's Review. She has a Bachelor of Commerce from the University of Ontario Institute of Technology and a postgraduate diploma in small-business management from George Brown College.