Most likely your bath bombs are breaking due to the type of liquid you are using in your mix to bind it all together. Most people will use Witch Hazel or a little bit of water but both of these ingredients will actually start the fizzy reaction between your sodium bicarb and citric acid not allowing the mix to stick together. High proof Isopropyl Alcohol or Denatured Alcohol is recommended as a binder. The alcohol evaporates out as the bath bombs dry leaving you with great smelling, high quality bath bombs. This issue is very common ecspecially with makers that go from producing bath bombs by hand to making them with a bath bomb press. A bath bomb machine is a great way to increase your production and will help you produce rock hard, well compacted bath bombs.