Can I use my 30.5 % solution of NaOH?

[andreja]

SO, before I found solid NaOH I bought 30.5 % solution (NaOH only), but then I saw that I need at least 38%. So, is my only solution to add solid NaOH to the solution to get the right percentage or are there some recipes where I could use this solution alone? Maybe I can use it in recipes that use a lot of solid at room temperature oils?

 

[Deda]

I've never used a purchased premade lye solution. I make my own 1:1 solution.
I've seen sold them in hardware stores.

I think the 38% you are referring to is 38% of the weight of your oil. Not a helpful number if you are using a premixed lye solution.

A 30.5% lye solution is 30.5% NaOH and 69.5% something else, hopefully water.

When you use a premix (purchased or a solution you made) you would calculate your recipe based on how much lye to saponify your oils, less your chosen superfat value. Your lye solution could be as high as 50% or as low as you choose to go. I think soapcalc recommends 28.5% A super low concentration uses way more water than you need resulting in a longer cure, more chance of DOS and possible warping during the cure.

So to answer your question, yes you can use it. Use it in any recipe you want, IF you are sure of the solution %, an exact number, not a range and you are CERTAIN that the remaining 69.5% is just water, nothing else.

It's early, my DH hasn't made the coffee yet, so if I've totally missed the boat on this one, blame it on him and the late coffee...

 

[andreja]

I think the 38% you are referring to is 38% of the weight of your oil.

Yes, exactly. I don't know why I thought it has to be 38% of lye in water solution. I am chemist for pete's sake.
But still, from quick calculation of lye solutions, I get at leat 50%, so wouldn't soap made from much more diluted lye make too soft soap that takes really long time to cure?
As for how sure I am if it's really only lye and if it's really 30.5%. It says so on the label. Shouldn't they put on, if there is anything else?

 

[Deda]

But still, from quick calculation of lye solutions, I get at leat 50%, so wouldn't soap made from much more diluted lye make too soft soap that takes really long time to cure?

I'm not sure what you are referring to? Where are you getting 50% from?

Full water soapers use a solution of 28% lye and 72% water. I soap at a much higher concentration, 40% lye and 60% water.

 

[andreja]

OMG, I am sleep deprived, but I didn't know I was THAT sleep deprived!!!
So what I did was: mass of NaOH/mass of water, where I should calculate it mass of NaOH/mass(water+NaOH).
I don't think I am worthy of chemist title.


Thanks!!!

 

[Val]

I am not certain of this but I believe Soap Calc has a place you can enter the solution water : lye so it would give you the amount to use.

If this is not correct someone please let me know

Val

 

[andreja]

MMS calculator has a choice of solution or solid NaOH. I was playing now with it and it says that we have to use at least 30% of a solution.

 

[carebear]

yes you can soap with it.

run soapcalc.com with a 30.5% solution entered. then click view/print recipe and you will see how much water and lye you need. since your solution is already made up, simply add those two numbers together and use that amount of your pre-made solution.

For example: for a 1# batch of 100% coconut oil you would need (assuming 30.5% lye solution)

Water 179.93 grams
Lye - NaOH 78.962 grams

yours are already combined in your premade solution so you need 259 grams of the solution.

 

[andreja]

Okay, now I see where I can put in my lye solution on soapcalc! Thank you!