The main ingredients are baking soda, citric acid and corn starch, which also holds everything together. Try experimenting with different scents and colors.

Mix liquids in a separate container


Make sure to use two different bowls for mixing the ingredients, one for the powders and one for the liquids. Mixing the liquids at the sametime will activated the mixture.

  • 1/2 cup Baking Soda
  • 1/4 cup Citric Acid 
  • 1/4 cup Cornstarch 
  • 1/4 cup Epsom Salt (or sea salt)
  • 3 tsp Castor Oil (or any vegetable oil)
  • 1 tsp Essential Oil 
  • Soap or Food Coloring
  • 1 tbs Water

Mixing the liquids

To keep the ingredients from activating while mixing, you’ll want to add oils, scents and dyes in small amounts at a time.

Once it’s all nicely blended, we’ll need to pack the mix into the molds as tightly as possible.

Packing molds

Pack the mold by layers, making sure to pack each layer down as tight as you can.

It’s a good idea to pack more than necessary so the two halves fuse together.

Join molds

Join the two halves together by pressing them tightly and remove the excess from the sides.

Try to smooth out those edges so there’s less of a seam.


To hold the two parts together, we can use a few rubber bands while the mold dries. We can let the bath bombs dry overnight.

For faster drying, you could pop them in the freezer for about 15 minutes.


With our mix fully dry, we can demold by tapping and squeezing on the sides until they come loose.

Now there we have it! An icosahedron bath bomb - super cool!

Toss in the tub and enjoy!

These are great to customize with different colors and scents and it’s  a lot fun for kids!

This guide was first published on Feb 11, 2016. It was last updated on Feb 11, 2016.

This page (Assembly) was last updated on Feb 09, 2016.

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