Shaving soap with NAOH and KOH?

[dosco]

How do you calculate or using BOTH KOH and NaOH in the same recipe? On soapcalc, using the same oils calls for 26.6% NaOH or 33.3% KOH. Not that common sense always works in soaping, but it would dictate one would calculate the recipe twice based on the Percentage of oils used (e.g. 40% of total oils with KOH and 60% with NaOH) then blend the two. Does that make sense? Is there a calculator online that allows you to combine the two in the same formula? Am I making this more complicated than it needs to be? Why am I asking so many questions? Is anyone reading this? Am I being paranoid? What was in those 'shrooms I just smoked?

I don't know if there is a calculator to allow for both but the way I do it is to split the recipe. I also use HP. There are a couple of ways to split the recipe, my way is to formulate and saponify the batches separately (KOH+stearic, NaOH+lard+CO). While hot I then bring them together for the final mixing.

The reason for this is that I want my shave soap to have certain finished properties. I want the KOH to only saponify the stearic, and I want the superfat to only be coconut oil. I also want certain percentages of constituent fats/fatty acids (I currently use 50-25-25 stearic-lard-CO). So I use soapcalc to determine the KOH+stearic formulation, then I use soapcalc to determine the NaOH+lard+CO formulation ... making sure all the time to keep the mass of the fats/FAs in the proper proportions.

When I go to make the soap I start by melting the lard, then adding all of the NaOH+water. Once suitably thickened I add the CO.

In a separate pot I melt the stearic and then add KOH. This stuff reacts almost instantly and is "done" (enough for mixing) very quickly.

I've read on other threads of the same formulation method (separate recipes) but then mixing everything in 1 pot. This will work but I don't like it for 2 reasons.

1) the SF will be a mix of stearic, lard, and CO. Which may be fine (functionally it is not a problem) but I happen to like CO as *the* SF.

2) The KOH will saponify the stearic, lard, and CO. My understanding is that the "secret sauce" that makes shave soap "good" is the potassium stearate.

As they say on the shaving forums, YMMV.

-Dave

 

[LBussy]

Dave the separate saponification may be a placebo effect ... maybe not, but see this thread we had a week or so ago:

http://www.soapmakingforum.com/showthread.php?t=49216

This calculator does mixed lyes:

http://summerbeemeadow.com/content/advanced-calculator-solid-cream-or-liquid-soaps

 

[DWinMadison]

So, You mix the KOH directly into the stearic with not dissolving in water? Will that work in CP?

 

[LBussy]

No .. almost positive he did not mean it that way. You have to dissolve the lye in something.

 

[IrishLass]

So, You mix the KOH directly into the stearic with not dissolving in water? Will that work in CP?

Ditto what Lee (LBussy) said^^^.


IrishLass

 

[dosco]

So, You mix the KOH directly into the stearic with not dissolving in water? Will that work in CP?

No. My apologies for my imprecise language. I meant KOH+water solution.

I suspect it is unlikely you'll get stearic to work with CP.

-Dave

 

[The Efficacious Gentleman]

Unlikely is an understatement!

I'm still not sold on how much a saponified soap will interact with an additional oil to be honest. Eagerly awaiting Dr Dunn's results on that.

Dave - even if you do one pot hp you can still selectively superfat - work out a lye neutral or 1% sf recipe, cook it up and then add in co to the amount you want (50g for a 5% sf in a 1kg batch) and there you have it.

Just for info, both this method and the method Dave usually follows have an interesting effect - While this is a superfat of 5% it is not likely to be a lye discount of 5%. When selectively superfatting, the amount of lye used is not the total required minus 5% (keeping the 5% example) because of the different SAP values.

 

[dosco]

I'm still not sold on how much a saponified soap will interact with an additional oil to be honest. Eagerly awaiting Dr Dunn's results on that.

My thoughts on my approach is that after I've added *all* of the lye water to only 1 of the fats, by the time I add CO the lard has *mostly* saponified. I'm going to guess that *mostly* means something like 80% to 90% ... and although I'm not a chemist I do recall from my college chemistry that the rate of reaction - being an exponential function - results in a small amount of saponification over a long time. Much what I've read about here and elsewhere about "curing." So I realize that my approach probably yields a small amount of lard as SF, but I'm speculating it's on the order of less than 1% and with a 5% SF that's not much.

If the lard was fully saponified I am dubious that there would be any reactions at all with the CO. But there is no way for me to know if the lard is fully saponified due to the massive excess of lye. I'm banking on the fact that CO appears to react very slowly (based on my observations making CO-only soap) and that by the time I've added the CO to the mostly saponified lard-soap that I'm guessing that what I've said in the previous paragraph is true.

Dave - even if you do one pot hp you can still selectively superfat - work out a lye neutral or 1% sf recipe, cook it up and then add in co to the amount you want (50g for a 5% sf in a 1kg batch) and there you have it.

If I were using 1 lye I would definitely try that. Similarly if I were using *zero* stearic I would also try that. But because shaving soap needs potassium stearate it makes sense to me to use the 2-pot approach or the 1-pot with addition of finished stearic-only soap (sort of a rebatching method).

The conversation about cations switching species is interesting. I do know a teeny bit about metallurgy (the "lamellar" comment brought back some memories from my last job) and heat treatment and it is interesting to note how one can make various metallic compounds go in and out of solution by heat treatment. Seems like a parallel here with soap.

On a similar note, do the Na and K ions switch between their respective FAs or do they switch with all FAs? In other words if I were to make a soap with KOH and NaOH would the metal ions switch only between the stearate molecules? Or do they switch between the myristate, stearate, and all other salt molecules?

And how much switching are we talking about? I would posit that it is a small amount at room temperature and there is more switching as the temperature increases.

Cool stuff.

Cheers-
Dave

 

[LBussy]

I suspect it is unlikely you'll get stearic to work with CP.

There is a new soaper on B&B (she's not on here) that makes a CP shaving soap with SA. I'd guess she melts, mixes in oils and cools it to where she can work with it. It would almost have to be "warm process" but ....

My thoughts on my approach is that after I've added *all* of the lye water to only 1 of the fats, by the time I add CO the lard has *mostly* saponified.

My first HP soaps were "done" in 20 minutes by zap test. Depending on how long you are going there I would agree.

So I realize that my approach probably yields a small amount of lard as SF, but I'm speculating it's on the order of less than 1% and with a 5% SF that's not much.

Since I add my SF after a 2 hour cook, I doubt very much I have any unintended fats as SF. Still as we said in a thread on B&B - I smear more grease on my face eating BBQ than I do shaving.

On a similar note, do the Na and K ions switch between their respective FAs or do they switch with all FAs? In other words if I were to make a soap with KOH and NaOH would the metal ions switch only between the stearate molecules? Or do they switch between the myristate, stearate, and all other salt molecules?

The way the literature I've found reads, the cations are free to switch around with any available FA. Since only reacted FA's are available (SF would not be in solution) I take that to mean between the saponified fats.

And how much switching are we talking about? I would posit that it is a small amount at room temperature and there is more switching as the temperature increases.

I've no reason to not believe the laws of physics would not hold here. Still, the assumption is that it happens at the molecular rather than macro level so a couple here and there, likely not enough to change the character of a soap used within a year. I don;t have a way to test that but it seems reasonable.

Since I've absolutely no reason to use NaOH in my shaving soap I also don;t worry about it too much. :grin:

 

[The Efficacious Gentleman]

It's strange - I actually get better results from my mixed lye soap than my KOH.

 

[LBussy]

It's strange - I actually get better results from my mixed lye soap than my KOH.

Yes, it is strange.

My pure KOH soap is now as hard as most mixed lye soaps (within an hour of cooking), and still loads like an Italian croap. I could probably puck this soap, although it would need a touch of curing/drying. I just prefer tubs and tins.

The only folks who seem to have trouble with it are those who are used to low-solubility soaps and/or don't use enough water. Those are the same folks who have trouble with MdeC I think.

I was always "going to try this" but never got around to using both lyes. In the spirit of us badgering Irish Lass to try a soap without dirt, I should really do this in an upcoming session.

 

[DWinMadison]

It's strange - I actually get better results from my mixed lye soap than my KOH.

"Better" as in a better shave soap?

 

[The Efficacious Gentleman]

Not necessarily. But from my two soaps I get better shaves from the mixed lye one. Your mileage will vary!

 

[IrishLass]

. In the spirit of us badgering Irish Lass to try a soap without dirt, I should really do this in an upcoming session.

Well, that gives a whole different meaning to the name 'Badger and Blade'. lol


So far, for the most part, I've been using a 64% KOH/36% NaOH blend, but I really should try a 100% KOH batch of shaving croap.

I actually use 100% KOH quite often, but it's only for when I make liquid soap. The first stage that liquid soap goes through is the 'paste' stage, where the initial batter saponifies into a thick, hardened-but-pliable, translucent, taffy-like soap that can be squished and formed into whatever shape you desire. And it will remain in that hardened taffy/paste state until you dilute it with enough water to turn it into liquid soap.

Lee- maybe you should try making liquid soap out of your 100% KOH shaving soap one of these days.

Oh, just wanted to mention that with the last batch of 64/36 shaving croap I made, I mixed the 2 lyes together with all my oils/fats instead of separating them to saponify with different fats, and we found no noticeable difference in the finished croap. It behaved the same as my croaps made with the 'separate saponification' method.

I must say that I really love making these croaps. They're hard and can hold their shape, yet they are still soft enough to be squished up and pressed form-fittingly into a bowl or a cup, or whatever else you desire to package them in.


IrishLass

 

[LBussy]

Maybe someone can explain to me what benefit - real or imagined, comes from using NaOH? NaOH is harder and KOH is more soluble so if I don;t care how hard it is and I definitely want solubility, why use any NaOH?

 

[new12soap]

Maybe someone can explain to me what benefit - real or imagined, comes from using NaOH? NaOH is harder and KOH is more soluble so if I don;t care how hard it is and I definitely want solubility, why use any NaOH?

I think it depends on your formula. If you are in fact using 50% stearic acid, or a very high percentage, you can still get a soap hard enough to hold its shape and mold into a container, something putty-like. If your formula contains far less or no added stearic, you would end up with LS paste using only KOH. The NaOH gives the soap more form.

 

[LBussy]

So if a given soap is "hard enough" with KOH, why mess with two different lyes? Is there any other benefit?

 

[DeeAnna]

"...maybe you should try making liquid soap out of your 100% KOH shaving soap..."

I don't think I've ever heard anyone ever comment on this, but I realized recently that the Songwind recipe (Martin de Candre dupe) is basically a cream soap. The stearic % and added glycerin is right on the money for this type of recipe. Just add a little more water and whip it good. :twisted:

Add even more water and, yes, I agree with you, Lass, it would make an opaque liquid soap.

 

[The Efficacious Gentleman]

A wee update - used the KOH only soap with lots of water and had a top notch shave. The cat is firmly amongst the pigeons now.

As for puck vs croap, Lee, you don't have to - as you know, some people like pucks a lot. I did a 50/50 mix and my hard puck performs really well. I will make both as some people will like a puck regardless of if the reduced amount of KOH makes it slightly less effective. Let's be honest, it still have NaOH with the right fats mix so it's not a complete ruin of a shaving soap.

Dave, the comment from irishlass was what I was thinking of before, that the 2pot method to get only potster might well be a goose chase. Maybe also make up a small batch and see?

 

[dosco]

As for puck vs croap, Lee, you don't have to - as you know, some people like pucks a lot. I did a 50/50 mix and my hard puck performs really well. I will make both as some people will like a puck regardless of if the reduced amount of KOH makes it slightly less effective. Let's be honest, it still have NaOH with the right fats mix so it's not a complete ruin of a shaving soap.

I suspect Lee's reasoning is something like "we know that potassium salts are more water soluble than sodium salts, so shave soap should only be made from potassium hydroxide." Not saying that's what he really thinks but the reasoning is sound.

My first shave soaps were 100% KOH and were excellent. I started using NaOH and lard because one of the guys on Shave My Face forum sent me a piece of his shave soap made from those ingredients. I tried it and didn't notice a difference in performance ... and I can get lard and NaOH locally rather than reliance on internet ordering tallow and KOH.

Dave, the comment from irishlass was what I was thinking of before, that the 2pot method to get only potster might well be a goose chase. Maybe also make up a small batch and see?

The main purpose of the 2-pot method is to ensure CO is the SF. I am confident that it works although I have no way to empirically determine this ... so if I make a test batch how would I test it to objectively quantify the difference?

(side note: my first batches were formulated from single-oil soaps that were all made to be 5% SF ... so the final product had unsaponified tallow, stearic, and CO)

(side side note: Lee's point about the actual amount of unsaponified fat is not lost on me ... to be totally honest I'm not overly worried about it either way)