Hello Karen,
Good question, long answer. You might also want to search the Orchid
archives as this has been discussed in various forms on Orchid
before.
... The recipe that I have seen calls for a 50/50 mix of borax with
denatured alcohol.
I use this stuff all the time and I think you’ll find that the 50/50
thing is totally arbitrary. Use whatever ratio you like to get a
paste that suits your purposes. The alcohol is long gone before the
borax begins to melt so the ratio you mix it to has no effect on
it’s fluxing function.
... when I ask for denatured alcohol people look at me like I'm
nuts!
As someone else pointed out the “denatured” part of denatured alcohol
simply means that they’ve added something to it to make it poisonous,
ie. so you won’t drink it. In other words if you ask them for alcohol
(like folks have said, paint stores, pharmacy, etc) and you look at
the ingredients and it says “95% ethanol, 5% (whatever)” and the label
indicates that it’s poisonous then you’ve got denatured alcohol
whether the label says it or not.
Is there another name it might be known by?
Yes, many. If you have access to a decent hardware store or paint
shop ask them for shellac thinner and then read the ingredients. If
it says “ethanol” or “ethyl alcohol” then you’ve got what you need.
Ethanol is the traditional thinner for shellac and works like a
charm. It’s best if the percentage of ethanol in the “thinner” is
high, say 90 or 95%. That means that it’s relatively unadulterated and
therefore likely to give better results. It also means that when you
burn it you won’t be burning additives and releasing nasty by-products
into your air supply.
I have no problem finding isopropyl alcohol, but I think that has a
different chemical makeup?
Absolutely! And it doesn’t work worth a tinker’s damn. You’ll find
that it makes your flux clump up into nasty balls and you’ll have an
opportunity to learn some new swear words. Go ahead and try it, it’s
not going to cost you much to find out that it isn’t what you want to
be using.
The main reason that isopropyl is so useless is that it is almost
always liberally cut with water and water makes borax clump (try
adding a little water to powdered borax and you’ll see what I mean).
FWIW, there are three main types of alcohol: ethanol, methanol and
isopropanol.
It has been suggested that wood alcohol (aka methanol) is the best
thing for your needs. Given that it is poisonous, both in liquid and
vapour form, I’d suggest you might want to think twice before you go
there. Methanol is what some people drink when they want to go blind,
induce a coma or kill themselves.
I don’t know if this helps any but ethyl alcohol is what we humans
like to drink, we call it booze. It doesn’t matter whether it’s vodka
or tequila, beer or wine or anything else: the feel-good part of the
mix is ethyl alcohol. It also happens to be great in the shop because
it’s not, in itself, poisonous and it functions almost as well as
methanol in most applications.
Isopropyl alcohol is what you doctor might use to disinfect a spot
on your skin before he gives you a needle. It’s also widely used in
industry as a degreaser and cleaner. The industrial grade is usually
around 75% pure. Pharmacy grade stuff is usually around 30% pure
and may have any number of pesky things in it including methanol and
ethylene glycol, both of which are poisonous. It also includes a lot
of water which makes it useless as a mixing agent for borax flux.
Finally, there are much more effective flux mixtures that you can
brew up at home. Pripp’s is the oft-mentioned one on Orchid. But if
you’re having trouble finding simple stuff like alcohol this approach
might be more hassle than it’s worth to you. As someone suggested you
might just be better off going to a welding shop or good hardware
store and buying a pre-mixed silver solder flux.
Cheers,
Trevor F.
in The City of Light
The I’ve learned by reading this forum