Help with lye premix

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Well-Known Member
Aug 1, 2009
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Pickens, SC
I'm trying to master batch lye for the first time :?
If I want to use a 50% solution (half lye/half water by weight -cooled and bottled in plastic (chlorox bottle ?)

If my recipe calls for
water 1032 g and lye 383 g = 1415 total

I would use 766 g of lye premix (383*2)

and subtract the NaOH weight from water amt (1032-383= 649) 649

So I would use 766 g of lye premix and 649 of water - Is this right ?

Thanks in advance for your help.
I normally soap with 33% solution, so what I do with my 1:1 lye solution is calculate the lye I need and then pour 2* that amount of my MB, and then add water (or aloe juice) = to my lye weight.

I only use the calculation above when I want to soap with a different concentration than 33%
Thank you all. And yes Susie. I hate math too but was determined to sit down and figure this out. It wasn't hard , my brain just resisted it ! LOL
Had a little problem with the process. I weighed and measured the lye/water. I stirred well (or so I thought). The next day - I had not only the small amount of surface crust but some clear sludge in the bottom. I kept gently prying and stirring until I was able to get it all liquid enough to pour into a storage bottle. IS it okay ? Did I not stir enough ?
Thanks Charlotte
Charlotteda, when you made your 50/50 solution, did you happen to add back the amount of water that evaporated when stirring/dissolving? That's what I do. I weigh everything before and after so that I can keep track of how much water loss I have from evaporation when mixing the solution. I usually have a loss of about 6 to 8 grams of water to evaporation. In a less concentrated solution, 6 to 8 grams of water might not be so much, but in a fully saturated 50/50 solution, especially one that has cooled off, 6 to 8 grams can be more critical. The crust on the top is just sodium carbonate, which I never worry about, but the stuff on the bottom may very likely be lye (lye always sinks to the bottom)....unless you also added silk to the solution or some other additive?

If it were me, I would just stir in a little bit more water at a time until the stuff on the bottom dissolves.

IrishLass :)
Thank You

Irish Lass & all,

Thank you for the reply. I never thought about evaporation.:???: I soap in another building so I usually mix the lye and go back the next day to soap.

I did as you said and added just a tiny bit of water and kept gently stirring and prodding until it was all liquid.

Thanks Charlotte

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