I have tried several different recipes for bath bombs and the best one that I have come across is Cocapinks Bath Bomb Recipe, my bath bombs come out perfect every time. My kids have even dropped them on the tile floor and they survive. Here it is: Part 1 Dry 1C. Baking Soda Wet 30gm Cocoabutter 5gm Shea Butter FO & Color Part 2 1/2 C + 2T. Citric Acid Melt all wet ingredients together and add to baking soda. Mix well. You should have a paste that is nice and sticky. Try to keep everything warm so cocabutter does not start hardening which may dry everything out (just pop into microwave for 20 seconds). Add Citric Acid and Mix until incorporated.You should have a mix that sticks together well, but still crumbles a little. If the mix is too dry (it shouldn't be) you can spray with FCO. If you are in a dry climate then up the cocoabutter by 5gms in your next batch.