Those pesky bath bombs

[Q-Lee]

First of all. I think I've read almost every thread and reply regarding bath bombs that don't behave. Do keep that in mind before replying
My challenge is that my bombs don't harden properly. Even after as long as 5 days they crumble quite easily.
And I feel/think it may come down to moist content in some mysterious way.
Through research it looks like about 6 -7% moist of total dry ingredient weight is whats recommended most places. (hard oils and soft oils, EO or FO and isopropanol 99% and water ) so that's what I've been experimenting most with. These bombs crumble easily, but do make an excellent fizzing!
Then in the other end I've tried to up the moist to about 14% (butters and oils) ,but then I think the bath bombs looks "oily at the surface" and of course...the bombs don't fizz a lot/ the way I want them to.
Still... I feel even these bombs also crumble a bit easily.

Maybe it's not right to compare home made bombs with the rock hard bombs from Lush,but it had been nice to have some descent behaving bombs to offer my customers.

So over to the questions..or thoughts I have
Is there a difference using corn starch vs kaolin clay to harden (e.g the cornstarch when moist "glue" stuff better together maybe)
What are the best- a higher ratio of soft oils vs hard oils. If soft oils are used at a higher rate maybe these would bind the bombs better together than a high rate of e.g cocoa butter
Is it possible that really really hard bombs just are achievable with professional mechanical or air driven presses, that compress the bomb mix better in the molds (in a way this make sense for me)

And in the end some facts.
The humidity is kept at 35-40 during making and drying the bombs.
I do use isopropanol 99%
The citric acid is in powder form and added as last ingredient.
I don't use liquid colors, just micas or similar colorants suitable for bath bombs

The recipe is in %

Baking Soda	64
Citric Acid Powder	30
Cream of Tartar	2
Kaolin clay	1,4
Goats Milk Powder ( I've also skipped this and replaced with clay or CoT or CA instead)	2	Dry ingredients = 100%
SCI	0,6
Polysorbate 80	1
Cocoa butter	2,7
Rice bran	0,7
FO or EO	1
Isopropyl 99%	2	Wet ingredients in % of the dry
Mica powder	0,4	7,34%

 

[lsg]

Here is the recipe that I use and the bath bombs turn out hard.
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.

 

[atiz]

I have to say my bath bombs are much simpler, but they are pretty darn hard.

I think the main difference is that I use epsom salt, which I found to be a great help regarding hardness.

I'm not very precise with the measurements because I found it doesn't make a big difference, but my proportions are ca. 52% baking soda, 26% citric acid, 10% epsom salts, 5% cream of tartar, 4% butters, 2% Polysorbate 80, fragrance, lake dyes.

They don't have any surfactants so they do not produce foam, but it's still fun to use them . I have been planning to experiment adding SLSa or something, but haven't gotten to it yet and I quite like these as they are.

 

[Q-Lee]

Here is the recipe that I use and the bath bombs turn out hard.
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.

Given i % you then use about 10,5% moist in form of cocoa butter. Do you think/feel the bombs are "oily" on the outside in any way?
I also see you use a 5% with slsa. Lots of bubbles but hows the fizz?
And have you tried Poly 80 incorporated in this recipe (to avoid color stains in the tub I mean)

I have to say my bath bombs are much simpler, but they are pretty darn hard.

I think the main difference is that I use epsom salt, which I found to be a great help regarding hardness.

I'm not very precise with the measurements because I found it doesn't make a big difference, but my proportions are ca. 52% baking soda, 26% citric acid, 10% epsom salts, 5% cream of tartar, 4% butters, 2% Polysorbate 80, fragrance, lake dyes.

They don't have any surfactants so they do not produce foam, but it's still fun to use them . I have been planning to experiment adding SLSa or something, but haven't gotten to it yet and I quite like these as they are.

Thanks . I tried Epsom salt in the recipe with about 14% moist (oils,butters,EO/FO etc) but those didn't turn out as hard as I wanted as mentioned. Do you use coarse or more finely ground Epsom salt? (mine ES is a bit like white sugar but a tiny bit more coarse)

 

[atiz]

Thanks . I tried Epsom salt in the recipe with about 14% moist (oils,butters,EO/FO etc) but those didn't turn out as hard as I wanted as mentioned. Do you use coarse or more finely ground Epsom salt? (mine ES is a bit like white sugar but a tiny bit more coarse)

Mine is about white sugar size as well. I don't make them very often and I'm also always worried whether it will end up hard enough, but so far always ended up with super hard ones. I think the cream of tartar helps quite a bit too.

 

[shunt2011]

My recipe is very similar to lsg. Mine are hard and package well. Not oily at all. I also package them after about 24-48 hours. I do add some PS80 to them.

 

[Q-Lee]

Thanks. A bit wiser

Mine is about white sugar size as well. I don't make them very often and I'm also always worried whether it will end up hard enough, but so far always ended up with super hard ones. I think the cream of tartar helps quite a bit too.

My recipe is very similar to lsg. Mine are hard and package well. Not oily at all. I also package them after about 24-48 hours. I do add some PS80 to them.

Any hint to how much PS80, preferably in %?

By the way.. What mold types do you all use. I've been using the 3D printed molds from The maker Shoppe. But maybe the stainless steel or clear pvc are better (so the bombs can dry a bit in the molds)

 

[lsg]

Given i % you then use about 10,5% moist in form of cocoa butter. Do you think/feel the bombs are "oily" on the outside in any way?
I also see you use a 5% with slsa. Lots of bubbles but hows the fizz?
And have you tried Poly 80 incorporated in this recipe (to avoid color stains in the tub I mean)

I haven't tried Polysorbate 80, but it would probably help to keep the dye or mica mixed with the bath water. I haven't noticed any oily residue on the outside of my bath bombs. If you want more fizz, cut down on the SLSA and use more baking soda and citric acid. Here is a link concerning the amount of polysorbate 80 to use.

https://www.soapmakingforum.com/threads/how-much-polysorbate-80-to-use.62462/

 

[shunt2011]

Any hint to how much PS80, preferably in %?

I use an equal amount to my oils/butter. I use metal molds for round or mooncake press.

 

[atiz]

I use PS80 half of my butter amount, but have been thinking of increasing it.

I don't have a press or even mold, so hand press it into a ¼ cup measuring cup... it works quite well

 

[Dahila]

Mine are hard like rock , I do not use any butter but Apricot Kernel oil in mine. 50/50 RA/Water

 

[Leslie Shannon Fisk]

Here is the recipe that I use and the bath bombs turn out hard.
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.

I dont ha

Mine are hard like rock , I do not use any butter but Apricot Kernel oil in mine. 50/50 RA/Water

I dont have SLS -- can we substitute with anything? I dont think I cAN GET it by Thursday and thanks.

 

[Misschief]

I dont have SLS -- can we substitute with anything? I dont think I cAN GET it by Thursday and thanks.

Try milk powder

 

[lsg]

I dont ha

I dont have SLS -- can we substitute with anything? I dont think I cAN GET it by Thursday and thanks.

What do you have on hand? If you have a liquid surfactant, then try using a small amount of that. If you have SCI noodles, then melt them with the coco butter and try that. As I stated in an earlier post, you don't have to use Sodium Lauryl Sulfoacetate , make up the difference with baking soda and citric acid.

 

[Dahila]

I do not use SLS I use Slsa and bioterge

 

[Gaisy59]

Hi all...i have made bath bombs in the past but just for personal use. A friend wanted to try one but was worried about how it would affect her lady “whoo haa” lol. I had the basic CA, BS, epsom salts and sweet almond oil. All your recipes seem to have so much more product in them. Would all that not cause irritation for women?

 

[lsg]

SLSA might cause irritation if the bather is sensitive to it. You can leave out the SLSA and cream of tartar, but you will need to cut down on the cocoa butter. I don't use Epsom salts in my bath boms. The best way to find out how a recipe works is to try making a small batch.

 

[Dahila]

It depens how much Slsa you add, I use 2 tbsp for 1400 grams of powder so no does not irritate, I have such difficult time with me eczema and I like to take a bath with bb and some of colloidal oatmeal, It calms the itching immediately . Very irritating is SLS, SLsa is something else

 

[Gaisy59]

 

[The Park Bench]

I have a bath bomb press and my recipe worked great until I colored my baking soda, added PS80 and slsa, now I can't get my bombs to stick together. Does anyone else with a bath bomb press have this issue?