First read over the directions that come with the putty. The tutorial is below but reading the directions first will give you a greater chance of success. Then measure equal parts of the purple and white putty. This can be measured by weight or volume.
Knead the two products together well with your hands. You should mix until there is a uniform color and no marbling.
Be quick when working with this product as it sets up fast! Flatten your mixed putty.
Add the putty all around your starfish or other object. All areas need to be covered. Then allow to set up according to the package directions.
Once cured, remove the object from the putty and you have a bath bomb mold!
How to make bath bombs:
First mix the Epsom salt, corn starch, baking soda, and citric acid in a bowl. NOTE: This recipe makes about five of the starfish molds shown. Next add in 5-10 drops of essential oil to scent and stir well.
Then start slowly dripping in water. NOTE: Every time liquid is added the citric acid will fizz. This is okay! Drip in a few drops of water at a time and mix well. Try to mold the mixture in your hand as shown below. Repeat until the mixture sticks together like in the image below. It should be fairly dry and powdery but will mold well when squeezed. Be sure not to get the mixture too wet.
Press the mixture into the bath bomb mold. Press well and get into all of the nooks and crannies. Place the entire thing into the fridge for one hour.
Pop the entire bath bomb out of the mold and allow to air dry for a day or two before handling.