Thank you! I would love the weight measurements. I hate measuring in cups too.
Here are the weight measurements for that recipe. I got the weight measurements by actually weighing the amounts as I measured them by cup, so the specific gravity weight measurements may not match the cup measurements completely. I use these weight measurements every time I make bath bombs, though, and it works well for me.
Dry ingredients:
Baking soda - 30 oz
Citric acid - 13 oz
Arrow root powder - 8 oz
Clay of your choice - 1.5 oz
Sodium Cocoyl - 1 oz
Mica - No weight measure, I just add until it looks like I want it to look.
Wet ingredients:
Epsom Salt - 4.5 oz
Distilled water - .25 oz
91% rubbing alcohol - .5 oz
Fragrance/essential oil - 1 oz
Sweet almond oil - 2 oz
Polysorbate 80 if you are using mica - .5 ounce
Notes on this recipe:
I use pretty small amounts of mica in my bombs. If you are using larger amounts, or darker colors, you might need more Polysorbate.
I don't use SLSA. You can purchase SCI from Nature's Garden for about the best price I have seen anywhere. Not using SLSA does impact how the bath bomb performs. SCI is more of a "bubble bath" type bubble, rather than the lengthened fizzy of SLSA.
These bath bombs will not win a competition for floating and spewing lots of pretty colors. They do an excellent job of creating a bath that moisturizes the skin, though. And, they smell great. I add other ingredients to these bombs, depending on "flavor". I use cranberry fibers in one, honey in another, etc. I do not alter the recipe at all when I use additives, and they still come out really nice.
By customer request, I make bombs in 3 sizes. I make a 4 oz, a 7 oz and a 10 oz. They start out heavier as you mold them, of course, and the weight of the largest ones as they dry sometimes cracks them. They don't crack apart, tho. I dry mine on bubble wrap to help prevent that. It doesn't always work, but my customers who like those enormous bombs don't care if they have cracks.