RogueRose
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Methyl vs Ethyl vs IP alcohol's in soap recipe
I've come across a number of recipes for melt and pour soaps and most call for ethanol (some say use strong vodka in place - although they don't call
for any reduction in H2O when doing this....) and some people have stated they have substituted rubbing alcohol (IPA kind, not ethanol type) in place
of ethanol and some have said they use denatured which was a high content of Methanol. Some state that Methanol can be used instead of ethanol. As
you can guess, some have said IPA and methanol don't work.
The problem is that I can't be certain that any of these people have really known what they are talking about due to some clues in the conversation
giving concern that they know the difference between the types.
The recipe is to make the melt & pour soap base which is later used to make the melt & pour soaps with more ingredients & melted once
again for the final soap product.
The recipe calls for:
Water
lye
palm oil
Coconut oil
castor oil
ethanol
glycerine
sugar water
The ethanol is about 12% or so (by weight) of the recipe.
I'm not sure if other recipes can use various alcohols, but I'm wonderinig how often it can be replaced for applications like this.
[Edited on 1-10-2015 by RogueRose]
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Darkstar
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Seems like everyone's confused, including you! 
Isn't melt-and-pour soap the kind that's already made, where you just melt it and pour it into the mold of your choice (hence the name)? The "recipe"
you're describing isn't for melt and pour soap, by the way, but to actually make soap from vegetable oils.
I've made soap a few times in the past and have never used any sort of alcohol. All you really need is fat and some NaOH or KOH. (in addition to any
coloring agents or scents you want to include) Just make sure you use an online calculator to determine the correct amount of NaOH/KOH to use based on
which oils you're using and their weight. Using too much will leave a bunch of unreacted lye in your soap. Not pleasant. Most people use slightly less
than stoichiometric amounts (superfatting).
Also, as far as the glycerine is concerned, glycerine itself is actually one of the main byproducts of the soap-making process. Saponification of the
triglycerides in the vegetable oils yields three molecules of the corresponding fatty acid salt and one molecule of glycerine. You can either leave
the glycerine in to give the soap better moisturizing properties, or remove it by salting it out. Some people do add glycerine to their melt-and-pour
soaps, though, as a lot of manufactures of melt-and-pour soaps remove it so they can resell it on its own. That might explain why it's on the list.
But if you decide to make your own soap, the reaction will produce plenty of its own glycerine.
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Sulaiman
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I can't comment on the chemistry because you did not give any
but personally, I would not make soap using methanol due to it's toxicity
not only would you be applying it directly to your skin
the methanol will slowly evaporate, building up methanol fumes.
And if a child was to ingest your product it is quite possible blindness could result
I use methanol, with ventilation, it is not scary toxic but there is a potential for harm.
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RogueRose
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I should have clarified the in the OP. This recipe is to make the melt and pour base soap.
Also, I'm not sure if the alcohol stays in the soap as I think it is cooked out as all the products are mixed together and heated to 170 degrees or so
for like 2 hours (maybe up to 4 hours) and then it is poured into a mould. The result is the melt and pour base which is later used with other
additives to make the end product soap.
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Fulmen
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I don't think it matters much, it's most likely there as a solvent. I don't see how it could react with any components in the mix.
We're not banging rocks together here. We know how to put a man back together.
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deltaH
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Do not use methanol containing solvents, this is a terrible practice!
Propylene glycol is a very safe, low-cost and readily available alcohol that can be used. Make sure you buy propylene glycol and not ethylene glycol,
which is toxic!!!
Here's a thread describing how to prepare propylene glycol melt and pour soaps, their associated problems and fixes:
http://www.soapmakingforum.com/showthread.php?t=31220
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