Blending Koh & Naoh...afraid I screwed up my math!

[ambers_artworld]

So I decided to try my hand at shaving soap tonight, using a blend of both koh and naoh. I was thinking that to determine how much of each to use, I would just do soapcalc for the full amount of both types, then multiply that number by the percentage of usage...example, if soapcalc says that using 100% koh would be 10 oz and 100% using naoh for the same recipe would be 20 oz, I would just multiply 10 x .6 (to get 60%) and 20 x .4 (40%) to come up with the amounts of each. Is this correct? I'm laying in bed wide awake thinking I waaaayy oversimplified the math and will have a caustic or gloppy mess waiting for me in the morning!! Any help appreciated!!!

 

[lsg]

A lye calculator for cream soap is what you need to use:
https://summerbeemeadow.com/content/advanced-calculator-solid-cream-or-liquid-soaps


You can melt cp scraps, add stearic acid and liquid soap to make a cream soap. Here is the recipe, but you will need to pay to view the lady's tutuorial video on the process:

Ingredients:
8 oz soap scraps
40 oz distilled water or infused water.
8 oz Vegetable Stearic Acid
20 oz Coconut Liquid Soap (this gives you the best lather, but you can
experiment)
2 oz Vegetable Glycerin
1.5 oz Aloe Vera Gel (or extract)
Follow the video as shown.
Leave the soap in a container for 1 or 2 weeks. Stir it, then leave it for up to a
month so it can settle.
Check in on it to see if has changed weekly.​

http://www.soapmakingschool.com/karmasudsclasses/classj36/

 

[fatfacedcharlie]

I regularly use both NaOH and KOH in my shaving soaps.If I want to get 60% of my lye from KOH and 40% from NaOH what I do is this: For a 500g batch, I enter the oils into soapcalc as percentages, then calculate the amount of KOH required for a 200g batch (40% of the total oils) and the amount of NaOH required for 300g (the remaining 60%), but don't forget to use the correct amount of water, just add up the water requirments for both batches. HTH

 

[DeeAnna]

Assuming you want to use 60% KOH and 40% NaOH in your recipe, then, yes, your method is correct because you are taking into account the different molecular weights of KOH and NaOH.

But even I would have used lsg's SBM link to doublecheck the calculations. :-(

 

[ambers_artworld]

Thanks so much everyone! Sounds like I should have used the SBM calc, but still a chance my soap will come out ok as long as my math was right. I guess now I just hold my breath!

 

[ambers_artworld]

So just an update, today I checked it and there is no zap, either on top bottom or center, but it seems a bit greasy and has little greasy pockets. The soap itself seems nice, with a pretty good lather right out of the mold...I'm just wondering if maybe it is the added glycerin? I added it at 10% of oils at trace, and have never worked with additional glycerin before...could that be what the slick feel and little sweating pockets are from? If not that, then I'm guessing I did my math wrong and didn't have enough lye in my mixture.

 

[DeeAnna]

Well, might want to be patient with this one. Check out Lindy and FatFacedCharlie's posts on shaving soap and see what they have shared. May get some more insight into what to expect. Congrats that your recipe worked out!

 

[bodhi]

What kind of a consistency do you get with a 60/40 batch? And congrats on it working!

 

[ambers_artworld]

Thanks guys! It's still very hard, even with KOH at 40%...next time I plan to set KOH at 60% and see how that goes. I was hoping for a semi-soft bar. I will see how the lather is after another week or two and will post an update (if I remember!)...hoping it turns out well