G’day; Lye is also known as caustic soda, but the correct
name is sodium hydroxide - as someone else in Orchid recently
pointed out. To confuse you, further, there are many other metal
hydroxides, like potassium hydroxide which is also caustic and
there is also calcium hydroxide (slaked lime) which is much
milder, but not very soluble, so it wont do much for you. In
caustic soda, (NaOH) and potash, (KOH) it is the OH part which
is responsible for cleaning - and dissolving flesh. You see, it
really likes fats, and the soap factories use beef fat (stearic
acid) and certain plant oils and fats (like palmitic acid) to
make soap. Most dirt has an oily or fatty component, and that is
why caustic soda goes for it - and makes the fatty bit into a
soluble soap. Soap has an OH molecule sticking out one end and a
fatty molecule sticking out at the other, and that is why soap
cleans; it can join with water or fats. So, heating a dirty item
with caustic soda in a ultra-sonic bath really works well, but it
doesn’t really need to be saturated; a 10% solution of NaOH
works. NOTE OF CAUTION: I personally think it unwise to put
caustic soda, (lye) into hot water - let alone boiling water.
Caustic soda reacts violently with water, and the solution gets
very hot - sometimes above boiling point for a few moments, then
the stuff is very liable to steam out of the vessel. Dont do the
mixing in a glass vessel either - I’ve seen more than one bottom
come out of a glass vessel in which caustic soda is mixed with
water. Always mix the caustic soda into water slowly, constantly
stirring. Do it the other way round and you’ll get a hard cake
at the bottom which will get extremely hot indeed. If you do get
splashed, then use plenty of water to rinse it off; hold the
affected part under the tap. Get any in an eye and you’ll need
to hold your head under the tap for at least five - ten minutes
whilst someone calls a doctor. Mind you, if you get caustic
solutions in an eye you’ll probably need someone to hold you down
too. Bloody PAINFUL!! But cheer up, it might not happen. If
you’re careful enough. Cheers,
/\
/ / John Burgess,
/ /
/ //\ @John_Burgess2
/ / \ \
/ (___)
(_________)