How much oil in a bath bomb?

[Snoralexx]

Hello all! I hope everyone is staying safe during the pandemic. I have been making bath bombs out of boredom and I'm looking for advice.
So far I do:

2 cups B.S.
1 cup Citric Acid
1/4 Cup Epsom salt
1/4 corn starch
1/4 tsp SLSA
1/2 tsp kaolin

I am looking for some guidance on how much almond/sunflower oil I should add as well as how much poly 80? Also if someone could explain how much POLY 80 I should use would be helpful. But I will take any advice that I can get! thank you in advance. If you think I should tweak something let me know

 

[atiz]

I don't always use butter/oil in my bath bomb, but when I do I usually use about 4% oil with 2% Polysorbate 80, or sometimes less of both.

 

[lsg]

I use coco butter in my bath bombs. It works better than oils for me. Here is a recipe I got a long time ago from the Kitchen Chemistry book.

No Fail Foaming Bath Bombs
1 cup Citric Acid (7.4 ounces)
2 cups Sodium Bicarbonate (17.3 ounces)
¼ cup of Sodium Lauryl Sulfoacetate (1.6 ounces)
¼ cup Cream of Tartar (1.4 ounces)
½ cup melted Deodorized Cocoa Butter (3.2 ounces)
1 tsp essential or fragrance oil

Note: Ounce measurements given in () are by weight.

Make sure to wear a mask or tie a handkerchief over your nose when working with sodium lauryl sulfoacetate as it is very powdery and can irritate bronchial passages. Mix all of the dry ingredients until there are no lumps and all is well blended. Mix in the melted cocoa butter and the EO or FO. Mix until all is well blended.

 

[nature coast]

I use the same amount of Polysorbate 80 as oil in my bath bombs. This allows all the oil to mix with the water. Without the polysorbate 80 the oil will sit on top of the water and make the tub slippery when getting out. It also helps bright colorants to mix with the water and no stain the tub.