Toddler Activities: Make a Mosaic Coaster


Toddler Activities: Make a Coaster with Plaster of Paris. Fill a coaster mold with plaster of paris, and embed some colored craft glass, buttons or other flat decor.
Make these cute coasters.


  • Plaster of Paris

  • Plastic mold can be found at craft stores

  • Container/cup and spoon or wooden disposable chopstick to mix plaster

  • Colored Craft Mosaic Glass (we used Cobbles)

  • Other items to consider using instead of glass: mosaic tiles, flat buttons.

  • Fine grade sandpaper


  • Mix plaster in container according to directions.
  • Fill Mold with Plaster until a little below the top. When you press the pieces of glass into the plaster, the level of the plaster will rise slowly.
  • Gently drop pieces of glass onto plaster. With tip of finger or popsicle stick gently press into the plaster until the item is level with the plaster.
  • Very carefully while on a flat surface, shift the mold back and forth gently to let all the pieces settle and create as flat a surface as possible. It must be done on a flat surface and very gently or you will cover the pieces.
making a plaster of paris coaster
  • Let dry for several hours for best results gently press behind the mold in a circle to loosen and then carefully pop the coaster out of the mold.

  • Use your fingernail to gently scrape off excess plaster on the glass pieces if needed. If there are any rough spots in the plaster, use a small piece of very fine sandpaper.

Tips and Suggestions

  • Due to the powder consistency of Plaster of Paris before adding water, handle the mixing of the powder out of reach of children. You might even consider using a face mask to prevent breathing in the powder.
  • For younger children use other items like mosaic tile that may be easier to handle and monitor. With bigger pieces, fill the mold halfway or three quarters.
  • Although Cobbles pieces are rounded to avoid injury, they are small pieces of glass so it must be monitored very closely.
  • We tried putting in the pieces first, then pouring the plaster on top with less than ideal results. The plaster tends to surround the item and get under it. It takes a lot more work to sand it to make the pieces visible.