“Frozen” Bath Bombs with color surprise

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Hello Everyone!
Here is my updated formula for bath bombs.
This time I have taken inspiration… no wait, I am sure you just cannot guess where I took inspiration from for these bath bombs 😉 it will stay a secret! ahah 😀
I know they look quite boring on the outside, but that’s because there is a surprise in the middle! 😉

I have made quite some experiments on bath bombs lately and I have also studied the formula for “the best bath bomb” from a chemistry perspective, so this is what I believe is the most effective formula at the moment.

Few notes:
– I didn’t add corn starch: it makes the water feel very soft/weird. I tried it in the past and I don’t like it. However, corn starch slows down the reaction so it is important to know if one wants to make a long lasting bath bomb.
– I didn’t add oil. There again: oil would have slowed down the reaction.
– I find the SLSA a very good add-on. This was the only powder surfactant I had, but others should work just as well 🙂 The best would have been to mix more powder surfactants together, but since it is just 4% and it doesn’t go directly on the skin I figured I could be a little lazy, formulation-wise.

Now, here is the FORMULA:

Citric Acid 47%
Sodium Bicarbonate 47%
Fragrance oil (cosmetic grade) 2%
SLSA 4%

Extras:
Ethyl Alcohol qs
Glitter (cosmetic grade – you can use micas) qs
Food grade concentrated color (water soluble) qs – I have used a very concentrated liquid water soluble blue color. At the time I didn’t have the powder form but that would have been a better option as some of the citric acid & sodium bicarbonate reacted to the water in the colorant.

Now to the HOW TO:

1) I measured the citric acid, the sodium bicarbonate, the SLSA. Mixed them slowly but very well (breathing the SLSA is definitely NOT GOOD – I did this process open air because I didn’t have a proper mask). Add also the fragrance oil, after the powders are well mixed, and mix again.

2) I added the glitter/mica. I added silver pearl mica (not much) and started spraying the powders with the alcohol while mixing them by hand (use gloves).

3) Keep spraying the alcohol and mixing until the powders are just slighly wet: enough to keep the shape if you squeeze the mixture, but still looking “sandy”.

4) Filled half of the mold with the bath bomb mix. I added a drop of colorant to the centre (powder would have been better but I didn’t have it)

5) I finished filling the mold and let the bath bombs dry for few hours

6) I took the bath bombs from the mold and placed them in a dry room. I live in a humid area and it would have been better to wrap them in film once dried.

I had a little bit of leftover bath bomb mix so I made a trial and here is the effect (I tried taking a video but I guess it’s not my thing… 😀 so enjoy the pictures!) 😀 :