Caustic Soda 98% w/w - good for soap making?

[atetard]

Hi all,
I'm new to the soap making world. I'm a beer brewer, and was keen to making my own beer soap :mrgreen:

I have a big question though.. I read everywhere you need to use 100% NaOH, but in the UK it's really hard to find (just like distilled water...).

So I've bought Caustic Soda from Boots (chemist), but it says "Sodium Hydroxide 98% w/w" ... and that's it! The other 2% are not outlined. So I don't know what else is in it, but I assume they'd have to write other ingredients/chemicals if there were any in the pack

Anyway, do you think it's safe to use, I've read diverging opinion, but I keep thinking it's worth a try anyway. I doubt it will actually dissolve my hand when I use the final product, but just want to be sure :mrgreen:

Thanks in advance to all you experts & passionate soap makers

Antoine

 

[DeeAnna]

Most NaOH used for soaping and other non-laboratory purposes is not 100% pure. I don't quite know what soaping authority is insisting one should use the 100% stuff, because that's a pretty unrealistic expectation. Most of the analyses I see are in the middle 90 percents. The product I use is about 96%, for example.

Even if you really were willing to pay for 100% pure NaOH, by the time you opened the container a few times, it wouldn't be 100% any more due to how fast NaOH reacts with water and carbon dioxide in the air. Your 98% product is probably better than most -- it will work fine.

Oh, and the "w/w" abbreviation stands for weight/weight basis. It means there are 98 grams of NaOH per every 100 grams of product.

You may also see "v/v" which is a volume/volume basis. Or w/v (weight/volume) or v/w (volume/weight). The amount "1 tablespoon ppo" (one tablespoon per pound of oils) is a v/w measurement.

 

[Sonya-m]

Nothing to add regarding purity but I'm in the UK and get my lye from B&Q, £4.99 for 1kg or £2.99 for 500g. You can also get it in Wilkos.

Also I just use de-ionised water from the petrol station which works fine, think I pay £2.50 for 2.5 litres

 

[spenny92]

As above, it's fine. I think the stuff I get online is 99%.