DIY Foaming Bath Bombs with SLSA
Classic bath bombs fizz, but adding Sodium Lauryl Sulfoacetate (SLSA) creates a fuller blanket of bubbles. This beginner-friendly formula also uses kaolin clay to support a firm, smooth bath bomb, shea butter for a richer bath feel, and Polysorbate 80 to help disperse the oils and color through the water.
Safety first: SLSA is a very fine powder. Work in a well-ventilated area and wear a properly fitted particulate mask, gloves, and eye protection. Avoid inhaling airborne powder. Keep all ingredients and finished bath products away from children and pets.
100 g formula
| Ingredient | Percentage | Weight |
|---|---|---|
| Baking soda | 48% | 48 g |
| Citric acid | 24% | 24 g |
| SLSA powder | 10% | 10 g |
| White kaolin clay | 6% | 6 g |
| Shea butter | 4% | 4 g |
| Polysorbate 80 | 5% | 5 g |
| Skin-safe fragrance oil | 1% | 1 g |
| Witch hazel, added gradually | up to 2% | up to 2 g |
Equipment
- Digital scale accurate to 0.1 g
- Large mixing bowl
- Fine-mist spray bottle
- Bath bomb mold
- Gloves, eye protection, and particulate mask
Method
- Put on your protective equipment. Gently combine the baking soda, citric acid, SLSA, and kaolin clay without creating dust.
- Melt the shea butter over low heat. Stir in Polysorbate 80 and fragrance oil.
- Slowly drizzle the liquid phase into the dry mixture while continuously mixing with a gloved hand.
- Test a small handful. It should hold together when squeezed but should not feel wet.
- If needed, add witch hazel one light spray at a time, mixing after every spray. Stop immediately if the mixture begins to expand or fizz.
- Pack firmly into the mold. Unmold carefully and allow the bath bombs to dry in a low-humidity room for 24–48 hours.
Troubleshooting
- The mixture expands in the mold: Too much liquid was added, or the room is humid.
- The bath bombs crumble: Add a very small amount of witch hazel and compress more firmly.
- Oil floats on the water: Confirm that Polysorbate 80 was weighed accurately and thoroughly mixed with the oil phase.
How to use
Add one bath bomb to a full tub of warm water. The oils may make the tub slippery, so enter and exit carefully. Discontinue use if irritation occurs.
References
- Oatmeal bath bomb method using shea butter, kaolin clay, and Polysorbate 80: https://tweakandtinker.net/oatmeal-bath-bomb-recipe-with-shea-butter/
- General SLSA surfactant context: https://en.wikipedia.org/wiki/Sodium_lauryl_sulfoacetate
This educational formula is for personal DIY use. Makers are responsible for stability, safety, regulatory review, and testing before selling any finished cosmetic product.
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