Hi
@Dwilson9, I’m not sure what you mean by a “modulator” - can you give an example of what would that be, and why would you want to use one?
While I sometimes use oils in my bath bombs, they definitely aren’t required as “carrier oils.” You also don’t need salts, and in fact, if you live in a high-humidity area, you will want to avoid them because they will draw moisture to the bombs and make them more likely to activate.
My current favorite recipe is based on the recipe shared on YouTube by Creative Bath Lab. The only ingredients are:
baking soda
citric acid
corn starch (I’ve also used cream of tartar or kaolin clay)
SLSa or SCI
PS80
FO/EO
color
distilled water
If you have trouble with your bombs activating, try adding the citric last, after everything has has been thoroughly mixed. You can also try a no-water recipe;
@lsg has shared a nice recipe that uses a bit of cocoa butter and no water.