My dad built a man made pond by damming up a valley years ago, when it leaked, they sealed it with bentonite clay. Now, I started making my own shave soap using a melt and pour base, and I order the same type of clay to add more slip to my soap. Many uses for this unique clay. Bentonite is actually a product of volcanic activity, and I believe most of it comes from the area of Mt. St. Hellens, in case anyone cares.
http://jabon-soap.blogspot.com/2009/04/receta-jabon-de-afeitar-shaving-soap.html this is a soap recipe with clay on it.I really love when a soap has clay on it..for me it makes the difference.
Bentonite and Kaolin clays have a different chemical structure, but it is the physical characteristics that make it useful for soap, and these are more similar. There are a lot of different types and grades of bentonite clay. Kitty litter is often made from a type of bentonite, but the type that is really in question here is a specific type of high grade bentonite that is very high in Sodium salts. The advantage of a high concentration of sodium salts is that they soften the water, which can improve the lather somewhat if you have hard water. If hard water performance is an issue, you can still use kaolin clay, but there are other additives that can be used to soften the water.
Yeah, baking soda is my softener of choice when I'm experimenting with surfactants. NaCl salt works, but I'm not sure it's as good. Salt does funny things to bubbles. I make bubble bath and salt will thicken the mix, then thin it when you add to much, it can support bubbles until it instead becomes antagonistic. You just can't win.
