# Bath Bombs cracking, please help



## ClaireMarquee (Jul 15, 2015)

Hello everyone! I'm new here in the soap making forums. Recently I started making bath bombs and have been running into some issues lately!

EVERY time I make a batch the bombs end up cracking horribly. This seems to happen no matter what I do...For reference here is the recipe that I use:

8 oz baking soda
4 oz citric acid
4 oz corn starch
4 oz epsom salts
.75 tbsp water
2.5 tbsp grape seed oil
2 tsp essential oils
plus I mix a little bit of dried herbs/flower petals in

The odd thing is the first two batches I made came out absolutely PERFECT. I use those plastic spherical molds and I was able to make perfectly round bath bombs with no cracks that worked beautifully. Cannot figure out what is going wrong now..Here are some photos of recent batches for reference:












I even started adding a bit of kaolin clay to the mixture, this makes them harder so they at least don't crumble but they still crack, as shown above...So they're functional but look really ugly. Which is a problem since I have to sell them..

To dry I pop em outta the mold (they seemingly come out perfect..) then leave them to dry..After about 8 hours they are still in good shape without cracks but then after 12 hours or so they begin to crack like this.

Any idea what I am doing wrong??


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## TVivian (Jul 15, 2015)

My suggestion would be to use a more solid oil in place of the grape seed oil. Coconut or Shea butter (or 50/50 of each) I feel oils that solidify a bit help hold the bomb together. Also, use alcohol in place of the water. I have trouble with my bombs doing weird stuff if I use any amount of water. Another thing, skip botanicals within the bomb. Use it on top or bottom, but mixing them inside causes voids where the ingredients don't bond, and therefore are more prone to cracking. Good luck


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## snappyllama (Jul 15, 2015)

Ditto to everything TVivian said.  I'll just add that bath bombs are very temperamental to humidity.  If humidity is different, you can expect different behavior from your bombs.  One way to help combat that is to go for more solid oils in your recipe as was previously suggested.  Also, save molding for rain free days.


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## Dorymae (Jul 15, 2015)

Yup, get rid of the water, up your oil to 3.5 and use a solid oil, coconut, Shea, coca butter, all work well.

And. . . Welcome to the forum!


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## Lynusann (Jul 15, 2015)

ditto to everything above. I use zero water and more solid oils. I don't currently use any clays and my bombs are nice and rock hard after 2 days. If you're in a humid place you might have more problems. Epsom salts can cause problems with retaining moisture as well if you're in a humid place.


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## handavaka (Jul 17, 2015)

When I've made bath bonbs, I set them out on towels and always placed a fan directly on them to deter them from absorbing any moisture from the air (as they do), and to dry them as quickly as possible.  My small bombs were baseball sized, and my large were the size of softballs, so the risk of them cracking was high, but using the fan really did eliminate that issue for me.  I hope this helps!  They are a great seller!


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## Relle (Jul 17, 2015)

Hi Claire

Good advice from the members above. Seeing you are new to the forum, and this is your first post, would you like to go to the Intro section and tell us a little about yourself so we can get to know you. It's nice to get to know people you are giving advice to.


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## Lilcat9984 (Jun 9, 2019)

TVivian said:


> My suggestion would be to use a more solid oil in place of the grape seed oil. Coconut or Shea butter (or 50/50 of each) I feel oils that solidify a bit help hold the bomb together. Also, use alcohol in place of the water. I have trouble with my bombs doing weird stuff if I use any amount of water. Another thing, skip botanicals within the bomb. Use it on top or bottom, but mixing them inside causes voids where the ingredients don't bond, and therefore are more prone to cracking. Good luck


That's what I use and it works wonderfully.


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## lsg (Jun 10, 2019)

I use melted cocoa butter instead of water,  Too much liquid can cause cracking.


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