# Bath Bomb Questions



## Viore (Apr 1, 2017)

I've been experimenting with bath bombs for a few weeks now, and I'm having such a hard time with making them fizz well. They also don't harden after a week of drying out; they are still soft enough I can dent them with my fingers. Here's the recipe I've been using (by weight):

4oz baking soda
2oz citric acid
2oz corn starch
2oz mix of epsom and dendritic salts
.5 oz avocado oil
.5 oz polysorbate 80
.2 oz fragrance oil

My questions are: how can I tweak the recipe to make the bath bombs more fizzy? Do I add a 1:1 ratio of poly 80 to avocado oil, or a 1:1 ratio of poly 80 to avocado oil and fragrance oil?


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## BattleGnome (Apr 2, 2017)

I don't make a ton of bath bombs, hopefully someone with more experience will be able to chime in as well.

The thing that jumps out to me is that you have a ton of salts and cornstarch. Everyone's "proper formula" is different but that's where I would start tweaking. PS80 is not going to add any fizzing, it's only purpose is to get your oils and colorants to mix with the bath water instead of floating on top. 

Addressing the salts directly, Epsom salts need nearly 2c to be considered therapeutic. If you are adding Epsom salts for therapeutic use, it's not currently working. At most they're working as a filler (I don't use dendritic salts and haven't done the research to know what they might bring to the party). Cornstarch can add to hardness but I feel you probably have too much. I also don't use cornstarch and can't offer more advice about it. 

My suggestion would be to decrease your cornstarch and salts to 1oz *total* or even less. You could also add SLS/A or cream of tarter to that 1oz of additives to boost some fizz. Again, I can't offer too much advice about it, my bath bombs are literally baking soda and citric acid. I am also refraining from commenting on your oil components since the weather plays a big role in how much to use (from your phrasing it doesn't seem like you have troubles with the bombs holding together, just the hardness).


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## lsg (Apr 2, 2017)

I suggest leaving out the Epsom and dendritic salts.  Instead of avocado oil, I use melted cocoa butter.


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## earlene (Apr 2, 2017)

I read that cream of tartar can inhibit fizz, but I decided to try a bit of it anyway and did not notice a difference, myself.  But then I only used about a quarter teaspoon because it was a small spice bottle and I didn't have much.

I also read that Corn Starch can contribute to yeast infections, so decided to leave it out of my last batch for my granddaughter.  I don't know if that is true that it contributes, as I don't find a lot of corroborating evidence, however I do find some info suggesting that it can aggravate an already existing condition, so thought, leaving it out might be a good idea.  

My most recent recipe I used was only Citric Acid and Baking Soda (plus oil, FO & Colorant), and I got a VERY fizzy Bath Bomb.  But it didn't last long.  I think other additives tend to make the fizzing last longer; slow them down some, so it lasts longer.  

As for why your Bath Bombs aren't drying, perhaps your area is too humid?  Or perhaps you need to use less liquid when making them?  Or both?


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## Dahila (Apr 2, 2017)

salt in bb will attract the moisture


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## Viore (Apr 2, 2017)

Thank you for the replies! I live in a very arid area (deserts of California) so humidity is not really an issue. I will try decreasing the amount of salts and cornstarch and see if that gets me a fizzier bomb. 

Is fragrance oil considered an oil when used in the 1:1 ratio of polysorbate 80 to oils?


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## Paul Kimberlin (Dec 14, 2018)

I have just started making them.. some success.. some failure.. ones i made first are realy hard.. just the way they should be.. the last ones i made.. just crumble. I dont know if im putting too much or too little oil in them .. im also adding some Kaolin clay powder as ive heard that help harden them.. but these last ones are really crumbly..??


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## Dahila (Dec 14, 2018)

Kaolin very often make them crumble, a lot of people do have problem while using Kaolin


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## shunt2011 (Dec 14, 2018)

I use a bit of kaolin in mine and fortunately have pretty good luck with it. It's taken me a long time to find the perfect recipe.  If you post your recipe as well as any additives we can help you troubleshoot. If they are crumbling they probably don't have enough oil/butter in them.  Now mind you, I don't make a lot of them anymore  as they aren't good sellers here.  Plus you can buy them really cheap at any store these days.


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## Paul Kimberlin (Dec 14, 2018)

shunt2011 said:


> I use a bit of kaolin in mine and fortunately have pretty good luck with it. It's taken me a long time to find the perfect recipe.  If you post your recipe as well as any additives we can help you troubleshoot. If they are crumbling they probably don't have enough oil/butter in them.  Now mind you, I don't make a lot of them anymore  as they aren't good sellers here.  Plus you can buy them really cheap at any store these days.


I may try adding coconut butter as its more of a solid butter rather than an oil.. it may help stop them crumbling..

Another question too.. hope i'm not asking too much here.. I have seen here many bath bombs with insets in the top with either soap flowers or soap miniature items on the top, NOT inset into it as such, but sitting in a inset of the bath bomb, like a bit has been cut of, a round inset made in the bomb before the soap flower or little items have been put in. Just wondering if there's a mould with an indentation to make the top with that hole in, or if it has to be made as a sphere, left to dry and cut out manually.. like the one in the picture..


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## shunt2011 (Dec 14, 2018)

You would need to adhere with something.  I've not seen one like that.  I know that most just put like lavender buds into the bottom of the mold first then add their bath bomb mixture on top.   I've not tried anything like that a I don't like floaties in my bathtub.


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## SoapAddict415 (Dec 14, 2018)

Maybe you could adhere a small top, like a water bottle cap to the inside of your mold to create the indentation?


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## Paul Kimberlin (Dec 15, 2018)

SoapAddict415 said:


> Maybe you could adhere a small top, like a water bottle cap to the inside of your mold to create the indentation?


i may try that with one of the plastic moulds, i wouldnt want to ruin my metal ones.. Thankyou.. great idea.


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## Paul Kimberlin (Dec 16, 2018)

Still having lots of problems making bath bombs.. i seem to wasting ingredients like they're going out of fashion.
I make 5 or 6 at a  time.. Day after i only have to touch them.. and they crumble of are still so soft they fall apart.. Beginning to loose my patience with them.. I mixed 360gm of sodium Bicarb with 170gm of citric and 20gms of cornflour for hardening.. added 15ml of sweet almond oil with mint choc chip FO.. spritzed with iso while mixing all together.. and made into 5 bombs and 2 pyramids.. day after.. they still fell apart .. Can anyone see where im going wrong.. before i chuck away the whole stock..?


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## Chris_S (Dec 16, 2018)

Paul Kimberlin said:


> Still having lots of problems making bath bombs.. i seem to wasting ingredients like they're going out of fashion.
> I make 5 or 6 at a  time.. Day after i only have to touch them.. and they crumble of are still so soft they fall apart.. Beginning to loose my patience with them.. I mixed 360gm of sodium Bicarb with 170gm of citric and 20gms of cornflour for hardening.. added 15ml of sweet almond oil with mint choc chip FO.. spritzed with iso while mixing all together.. and made into 5 bombs and 2 pyramids.. day after.. they still fell apart .. Can anyone see where im going wrong.. before i chuck away the whole stock..?



Im sure i will be corrected if im wrong and as i kinda lost interest fir the very reason your getting impatient they just went to dust. Most the recipes iv read use witch hazel this could be worth try. Given its winter here and it rains ALOT could it be where you are leaving them overnight? Maybe they are attracting moisture from the damp enviroment? These are just my guesses of possible causes and im hoping someone more experienced will chip in if im wrong


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## lsg (Dec 16, 2018)

Paul Kimberlin said:


> Still having lots of problems making bath bombs.. i seem to wasting ingredients like they're going out of fashion.
> I make 5 or 6 at a  time.. Day after i only have to touch them.. and they crumble of are still so soft they fall apart.. Beginning to loose my patience with them.. I mixed 360gm of sodium Bicarb with 170gm of citric and 20gms of cornflour for hardening.. added 15ml of sweet almond oil with mint choc chip FO.. spritzed with iso while mixing all together.. and made into 5 bombs and 2 pyramids.. day after.. they still fell apart .. Can anyone see where im going wrong.. before i chuck away the whole stock..?


Paul, here is a recipe I got from the book, "Kitchen Chemistry."  It seems to work for me every time.

No Fail Foaming Bath Bombs
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 use decorative individual silicone molds for my bath bombs and call them bath tabs. You can find them at a hobby store or at Amazon.com I let them set until they harden and then remove them from the molds. They stay together and are easier to remove from the mold. If you don't want to use sodium lauryl sulfoacetate, then just use 1/4 cup soda and a little citric acid to make up the difference.


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## alwaysme07 (Dec 16, 2018)

There are molds for these.


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## KathrynS (Dec 17, 2018)

I don’t know if there’s a difference between cornflour and cornstarch, but I always use cornstarch.  It sounds like the bombs aren’t getting wet enough to hold together.  Plus, (and this is big) I noticed you don’t have Polysorbate 80 listed in your recipe.  If that was an oversight, just ignore the next paragraph.
Poly 80 is an emulsifier that helps the oils disperse in the water, and it prevents the mica coloring from clinging to skin or the tub.  It also makes the bomb more foamy.  It is a must have.  I usually add it in at 1:1 ratio with the carrier oil, which for me is the almond oil. 
If your powder isn’t holding together like damp sand, adding in a tablespoon of Poly 80 will help a lot.  In my spray bottle, I have water & alcohol. 
You just have to play with it, but the Poly 80 is a game changer.  I put it in all my products, not just the bath bombs.  Amazon has it for pretty cheap.  Let me know if that helps!


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## Livx (Dec 17, 2018)

Paul Kimberlin said:


> Still having lots of problems making bath bombs.. i seem to wasting ingredients like they're going out of fashion.
> I make 5 or 6 at a  time.. Day after i only have to touch them.. and they crumble of are still so soft they fall apart.. Beginning to loose my patience with them.. I mixed 360gm of sodium Bicarb with 170gm of citric and 20gms of cornflour for hardening.. added 15ml of sweet almond oil with mint choc chip FO.. spritzed with iso while mixing all together.. and made into 5 bombs and 2 pyramids.. day after.. they still fell apart .. Can anyone see where im going wrong.. before i chuck away the whole stock..?



Your recipe is good. A good tip is to add 2 teaspoons of water to your fragrance oil and stir.  If you use a blender add it in slowly so it doesn’t activate. I know it goes against the rule of no water but it’s an excellent way to harden your bombs! They will crumble otherwise.



Livx said:


> Your recipe is good. A good tip is to add 2 teaspoons of water to your fragrance oil and stir.  If you use a blender add it in slowly so it doesn’t activate. I know it goes against the rule of no water but it’s an excellent way to harden your bombs! They will crumble otherwise.


 

Sorry food mixer not blender. 

Try 2 tablespoons oil, 2 teaspoons water and fragrance and mix them all together. Then add slowly to your recipe.


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## Paul Kimberlin (Dec 17, 2018)

lsg said:


> Paul, here is a recipe I got from the book, "Kitchen Chemistry."  It seems to work for me every time.
> 
> No Fail Foaming Bath Bombs
> 1 cup Citric Acid (7.4 ounces)
> ...


Thankyou ... i may just try this recipe..i havent added a butter as yet to any bath bomb..



KathrynS said:


> I don’t know if there’s a difference between cornflour and cornstarch, but I always use cornstarch.  It sounds like the bombs aren’t getting wet enough to hold together.  Plus, (and this is big) I noticed you don’t have Polysorbate 80 listed in your recipe.  If that was an oversight, just ignore the next paragraph.
> Poly 80 is an emulsifier that helps the oils disperse in the water, and it prevents the mica coloring from clinging to skin or the tub.  It also makes the bomb more foamy.  It is a must have.  I usually add it in at 1:1 ratio with the carrier oil, which for me is the almond oil.
> If your powder isn’t holding together like damp sand, adding in a tablespoon of Poly 80 will help a lot.  In my spray bottle, I have water & alcohol.
> You just have to play with it, but the Poly 80 is a game changer.  I put it in all my products, not just the bath bombs.  Amazon has it for pretty cheap.  Let me know if that helps!


i have 3 ltrs of polysorbate 80.. i did actually put it in my first bath bombs.. they were okay.. its everything ive done since then, but as i didnt use mica, i didnt put any in.. i might just add it to every mix anyway.. Thankyou.
..
Determined to get there one day..lol..

Cornstarch is the same as Cornflour i'm led to believe, in the US its known as cornstarch, in the UK we call it cornflour.. a lot of ingredients go by different names so ive looked at loads of ingredients and made a list of what theyre called in the US against what we call them so as not to go wrong..


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## Livx (Dec 17, 2018)

Paul Kimberlin said:


> i have 3 ltrs of polysorbate 80.. i did actually put it in my first bath bombs.. they were okay.. its everything ive done since then, but as i didnt use mica, i didnt put any in.. i might just add it to every mix anyway.. Thankyou.
> ..
> Determined to get there one day..lol..



Good luck. They are difficult to master! Trust me on the water. They will get solid in an hour. I made a batch a few days ago and solid with no crumbling whatsoever


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## Paul Kimberlin (Dec 19, 2018)

Livx said:


> Sorry food mixer not blender.
> 
> Try 2 tablespoons oil, 2 teaspoons water and fragrance and mix them all together. Then add slowly to your recipe.


Trouble is though ..water doesnt mix with oil so thats a bit of a problem, i added some polysorbate 80 and it all turned to a soft runny gel.. so hopefully thats worked.. i have put them in an oven now up to 170.. and turned it off.. fingers crossed they dry out and are solid in the morning. I'm in blackpool and its really humid here.. rain in the winter.


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## Livx (Dec 19, 2018)

Should work! I mix mine water with my fragrances all the time and mine turn out ok. Just a teaspoon or less of poly not too much or they will bubble


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## shunt2011 (Dec 19, 2018)

I never use water, water can cause activation, I use 91% alcohol only of it needs a bit more wetness. Otherwise only use cocoa butter and some sweet almond oil or coconut oil with a bit of PS80.  No corn starch, I do add a bit of kaolin clay or cream of Tarter for hardness.


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## Livx (Dec 19, 2018)

shunt2011 said:


> I never use water, water can cause activation, I use 91% alcohol only of it needs a bit more wetness. Otherwise only use cocoa butter and some sweet almond oil or coconut oil with a bit of PS80.  No corn starch, I do add a bit of kaolin clay or cream of Tarter for hardness.



Water doesn’t cause activation if it’s mixed in very quickly. It’s gives the hardest bathbombs along with cream of tarter. I only use cornstarch when I’m using glitter as it makes the glitter sit nicely on top of the water.


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## shunt2011 (Dec 19, 2018)

That’s not my experience. To each their own.


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## Livx (Dec 19, 2018)

shunt2011 said:


> That’s not my experience. To each their own.



Appreciate that everyone has got their own different way of making bathbombs especially in different climates etc. I just found that adding some water helped with the hardening a lot. I used to be against water after everything I read.


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## Paul Kimberlin (Dec 20, 2018)

Right.. i made some last night using water, oil and i thing ..just a little too much polysorbate80 as, when i removed them from the oven, they had cracked.. but they are really solid. I did put in a little red glitter, with cornflour. I have just dropped one of the small ones 4cm ball, into some warm water and its taken about 6 or 7 minutes to fizz away.. maybe too much cornflour..?.. or is there a set time for them completely to fizzle out.. The previous ones id made, which ..to be honest were too soft or crumbly lasted about 1 to 2 minutes which i thought was too fast..?


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## Livx (Dec 20, 2018)

Paul Kimberlin said:


> Right.. i made some last night using water, oil and i thing ..just a little too much polysorbate80 as, when i removed them from the oven, they had cracked.. but they are really solid. I did put in a little red glitter, with cornflour. I have just dropped one of the small ones 4cm ball, into some warm water and its taken about 6 or 7 minutes to fizz away.. maybe too much cornflour..?.. or is there a set time for them completely to fizzle out.. The previous ones id made, which ..to be honest were too soft or crumbly lasted about 1 to 2 minutes which i thought was too fast..?




Getting there! should only take a few mins to fizz. The poly will make them fizz a bit longer. I’d say only about 30g or less of cornflower for your recipe and less that a teaspoon of poly. You only need a tiny amount to get good results.  I think the heat of the oven made them crack. I tried that before and same thing happened. Just leave them by a warm rad and should be ok.


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## Paul Kimberlin (Dec 20, 2018)

Livx said:


> Getting there! should only take a few mins to fizz. The poly will make them fizz a bit longer. I’d say only about 30g or less of cornflower for your recipe and less that a teaspoon of poly. You only need a tiny amount to get good results.  I think the heat of the oven made them crack. I tried that before and same thing happened. Just leave them by a warm rad and should be ok.


The trouble is though, as i live in a humid area, (Blackpool) if i leave them to dry by a radiator, there's still moisture in the air and thats why i think the outer layers were very crumbly.. the ingredients were reacting while drying out over a day..



Paul Kimberlin said:


> The trouble is though, as i live in a humid area, (Blackpool) if i leave them to dry by a radiator, there's still moisture in the air and thats why i think the outer layers were very crumbly.. the ingredients were reacting while drying out over a day..


I may try yo to reduc e the temperature of the oven to just 80 degrees rather than 170... so they don't dry out as quick.. also, i may have put in a bit too much polysorbate80 as they tended to flatten out a little on the tray in the over..


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## Livx (Dec 20, 2018)

Paul Kimberlin said:


> I may try yo to reduc e the temperature of the oven to just 80 degrees rather than 170... so they don't dry out as quick.. also, i may have put in a bit too much polysorbate80 as they tended to flatten out a little on the tray in the over..


Good stuff. They tend to flatten out if too much oil is used. 15g to every cup is good. Also,  keep your fragrance to around 2% and you’ll be good.


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## Paul Kimberlin (Dec 20, 2018)

right.. not too sure if i'm NOT using enough oil.. but they are hardening quite quick now.. heres my recipe for my tutti frutti snow pies..
500g Sodium Bicarb
240g citric acid
30g SLSA (Sodium laurel Sulfoacetate)
80g Cornflour
Pearl white mica
ice blue glitter

liquids..
5ml Sweet almond oil
3ml polysorbate80
30 drops tutti frutti FO
and added 3 - 4 tablespoons water once oils are mixed in.

This makes about 11-12 pies..

They dont look too bad.. i'd used coloured mica mixed with a little isopropyl alcohol to paint on the berries and holly and baubles..


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## Livx (Dec 20, 2018)

Not enough oil is a good thing!  it’s the water mixed in fast is the key. Cold freezing water. They look fabulous!


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## lsg (Dec 20, 2018)

Your bath bombs are very pretty.


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## Paul Kimberlin (Dec 21, 2018)

My next attempt is Jasmine cherubs.. i havent got a clue if it will work.. but.. here goes..

I had made these a few days back, i think i had tried to dry them too quick in the oven.. but rather than throw them away, i painted gold mica and turned them into Golden Earthquake bath bombs, oozing gold from the cracks.. why waste them.. a new design...


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## Livx (Dec 21, 2018)

Paul Kimberlin said:


> I had made these a few days back, i think i had tried to dry them too quick in the oven.. but rather than throw them away, i painted gold mica and turned them into Golden Earthquake bath bombs, oozing gold from the cracks.. why waste them.. a new design...



And you can always crush failed batches them up and put them into bags and call them bath dust or bath brew


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## Paul Kimberlin (Dec 21, 2018)

Pink Parma Violet Cherub Bath Bombs.. 2 turned out.. 3 lost their heads...lol.. i think the mould's are a bit too tough.. But i will try again..


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## Livx (Dec 21, 2018)

Paul Kimberlin said:


> Pink Parma Violet Cherub Bath Bombs.. 2 turned out.. 3 lost their heads...lol.. i think the mould's are a bit too tough.. But i will try again..



Pack lightly with your mix. Very nice


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## Loralei (Dec 22, 2018)

I melt a bit of cocoa butter and mango butter - leave out the soft oils.  Also, I add my liquids sooooo slowly, and mix, mix, mix... I do use Epsom salts, to soften water, kaolin clay, and even witch hazel... and mine have all turned out great (though I'm by no means an expert). 

The most important parts that I've learned is to slowly add liquids until the mixture feels like soft sand. If you can drop a clump back into your mix without it crumbling, it should be good to go.. my guess is the oils you've used are soft at room temp, so they won't ever dry properly..  hope this helps!


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## Paul Kimberlin (Dec 23, 2018)

Loralei said:


> I melt a bit of cocoa butter and mango butter - leave out the soft oils.  Also, I add my liquids sooooo slowly, and mix, mix, mix... I do use Epsom salts, to soften water, kaolin clay, and even witch hazel... and mine have all turned out great (though I'm by no means an expert).
> 
> The most important parts that I've learned is to slowly add liquids until the mixture feels like soft sand. If you can drop a clump back into your mix without it crumbling, it should be good to go.. my guess is the oils you've used are soft at room temp, so they won't ever dry properly..  hope this helps!


Thats the way i do them Loralei, i add the liquids very slowly.. mix, then a bit more and mix, i only use the minimal of oil now as a carrier oil for the fragrance oil.. so i'd say liquids are 40% Sweet almond, 3% F.Oil, 5 - 8% Polysorbitol80 and 50% water, quantities subject to the dry materials i use.. I was always told to pack tightly, although ive seen some say if you pack too tight, the bomb will sink, pack it too light, and it disperses in the water too quick..


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## Loralei (Dec 23, 2018)

Paul Kimberlin said:


> I was always told to pack tightly, although ive seen some say if you pack too tight, the bomb will sink, pack it too light, and it disperses in the water too quick..



I read about a million books/posts on BBs before making them; I pack very tightly, but I also incorporated the tip to press a little hole with my thumb in each side before putting them together - this apparently helps them float, and spin... I can't confirm that 100%, but my huge BBs did both!


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## Livx (Dec 23, 2018)

Paul Kimberlin said:


> Thats the way i do them Loralei, i add the liquids very slowly.. mix, then a bit more and mix, i only use the minimal of oil now as a carrier oil for the fragrance oil.. so i'd say liquids are 40% Sweet almond, 3% F.Oil, 5 - 8% Polysorbitol80 and 50% water, quantities subject to the dry materials i use.. I was always told to pack tightly, although ive seen some say if you pack too tight, the bomb will sink, pack it too light, and it disperses in the water too quick..



When your using moulds with the intricate designs like your cherub it best to pack slightly light because they will realise from the Mold easier. If you pack too tight they will get stuck and break. Round bombs pack anyway you want too but if you pack too tight they risk cracking in the middle. The best way I find is to really overfill both half’s of the molds without tightly packing and press together. This way you’ll get spinning floating bathbombs. They won’t fizzle out faster because the poly and the slsa will make them last longer. It’s only bombs with citric and bicarbonate that fizzle out the fastest no matter if they are tightly or loosely packed.


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