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Boric acid powder and alcohol flux


#1

I have a question.

Recently, a beginning student said to me that they were taught by
another jewelry instructor that boric acid powder in alcohol used as a
flux was toxic to use. That when lit it off-gassed toxic chemicals.

Now, I know how our community has become hyper sensitive to any
workplace pollution, but I remember spending years with only a window
next to me (no fan or vent) and using boric acid powder in alcohol as
a flux with no ill effects. I have checked MSDS for boric acid powder
only to find that it can be dissolved in water to safely rinse the
eyes.

I know fluorides used to be prominent in flux and were dangerous to
inhale, but am I missing something or was my student misinformed?

Nanz Aalund
www.nanzaalund.com


#2

Misunderstanding or misinformed. If there is less than adequate
ventilation it is the fumes of the alcohol before combustion which
can be a problem especially if it is methanol. The combusted alcohol
is CO2 and water vapor, not a big deal.

James Binnion
James Binnion Metal Arts


#3
Recently, a beginning student said to me that they were taught by
another jewelry instructor that boric acid powder in alcohol used
as a flux was toxic to use. That when lit it off-gassed toxic
chemicals. 

Has other posters have mentioned, the devil is in the details…

All alcohols are not created equally, and if the person uses
denatured alcohol which was denatured with some of the nastier
denaturing agents permitted (Suggested??) see
http://tinyurl.com/23zs2gv for the EU here is a less official source
http://tinyurl.com/2asxjnz

So has you can see the actual composition is somewhat of a
crapshoot, and since some of the denaturants

If the person uses methanol AKA wood alcohol then they are in for a
world of pain as this is quite toxic when evaporated. Isopropyl
alcohol is somewhere in-between

And if you want a real world of pain (for soldering at least) in the
US the BATF has also authorized the sale of denatured rum as
denatured alcohol, imagine the fun of the denaturing agents plus the
residual sugar from the rum production bubbling into a nice
carbonized mess on your solder joint.

Best to do has Jim (and other posters)

https://orchid.ganoksin.com/t/boric-acid-vs-borax

has suggested and just buy high proof drinking alcohol (although why
someone would buy 90 -95% pure alcohol to drink (the rest is water)
is beyond me)

See also


https://orchid.ganoksin.com/t/methyl-vs-denatured-alcohol


#4

It’s about as toxic as table salt. Don’t ingest or inhale in large
quantities. I use it to bathe my eyes.

Tony Konrath


#5
I know fluorides used to be prominent in flux and were dangerous
to inhale, but am I missing something or was my student
misinformed? 

I think your student was misinformed. Burning off alcohol to leave a
boric acid coating is just burning the alcohol. So far as I know, it
releases water and carbon dioxide like other hydrocarbons when
burned. If not enough air, there might be small amounts of carbon
monoxide, but this is not especially more true with alcohol, I don’t
think, than anything else one might burn in jewelry making (like your
torch fuel gas).

Heating boric acid doesn’t produce particular fumes since you’re not
vaporizing it, only melting it to a glaze on the metal in use. At
least, if there ARE some fumes there to avoid, I’ve never heard of
them… Fluorides in more complex fluxes do indeed pose risks in some
cases, but boric acid is not a fluoride.

The main dangers of boric acid and alcohol are that the alcohol
fumes themselves, when NOT lit, aren’t good to breath, and that,
obviously, the stuff is flammable. Don’t drop the jar in your bench
pan and accidentally set it on fire, for example…

Peter Rowe


#6

of course your torch could be producing toxic gases including carbon
monoxide

John


#7

Hello,

if someone realy want to dick into it one can estate that 2,4 gr/ kg
weight vor adult people can be deadly according what I found on
wikipedia. For baby’s it is even as low as 1,4 gr/kg weight. On the
other hand, this stuff is used to conserve caviar at a rate of 4 gr/
kg of caviar.

Drinking to much water can kill someone in a day aswell but nobody
cares about having to much water.

Have fun and enjoy

Greetings
Pedro


#8
that boric acid powder in alcohol used as a flux was toxic to use.
That when lit it off-gassed toxic chemicals.

Well, Nanz, first you need to define “alcohol”. And of course some
people’s definition of toxic is too stringent for words. Boric acid
in itself is reasonably safe, especially considering that you’re not
eating it to begin with. Denatured alcohol is used in Sterno and
lanterns, among other things. Methanol burns pretty completely,
meaning it leaves CO2 and water behind. So, there’s your “toxicity” -
not much. BUT - methanol vapors can be pretty bad for you - denatured
is not a lot better, if inhaled.

And the oxidation of methanol yields formaldehyde (a gas), that’s
also bad for you. That sort of oxidation is more like quenching a hot
piece in methanol, not in burning it. All of it is tiny stuff, with
normal, intellegent care and handling, though. Pretty paranoid…


#9

Thank you everyone for the I didn’t think the alcohol
off-gasses anything much worse than water vapor and CO2. The
ingredients labeled on the alcohol was isopropyl alcohol and
purified water.

But as Peter Rowe warned: “Don’t drop the jar in your bench pan and
accidentally set it on fire, for example…”

I did do that once and had no eyebrows for a couple of weeks. Wow,
that was a good look, try explaining that on a first date.

Nanz Aalund
www.nanzaalund.com


#10

I, too have used boric acid and alcohol for many years with no ill
effect. I would love to hear from those that know. Thanks Lynda

Lynda Rasco


#11
It's about as toxic as table salt. Don't ingest or inhale in large
quantities. I use it to bathe my eyes. 

Um. No. Don’t ingest at all. Boric acid is not as benign as table
salt when ingested. And the denatured alcohol you probably mixed with
it isn’t exactly safe booze either.

Peter Rowe


#12

We used boric acid and denatured alcohol at Texas Institute of
Jewelry Technology when I was in school. I don’t think they would be
using it if it caused any grave affects.They are very very caution
minded.

I continue to use it in my shoppe today.

Angela Hampton
Hampton House Jewelry


#13

Same here, used it for 35+ years and no -ch ch ch- problems - ch ch
ch… yet! LOL

Ed


#14

This is used primarily for firecoat so you don’t get as much or any
firescale on the object.

Russ


#15
If the person uses methanol AKA wood alcohol then they are in for
a world of pain as this is quite toxic when evaporated. Isopropyl
alcohol is somewhere in-between.

If I understand correctly, borax/boric acid will dissolve in methyl
alcohol, bit it is nasty stuff. It is merely suspended in ordinary
denatured alcohol, which is less toxic. Right? So I am wondering…
presuming that alcohols mix OK, would it work to dissolve your borax
in a small amount of methyl alcohol, then add denatured, to get the
solubility and minimize the toxicity?

Noel


#16

I am wondering if anyone in Australia has either found a supplier of
denatured alcohol or knows of a substitute that dissoves the boric
acid?

Anna Williams


#17
It is merely suspended in ordinary denatured alcohol, which is less
toxic. Right? 

Time for a reality check here. I’ve found that much of our younger
generation didn’t take chemistry, and it’s a mystery (and often
evil) to them.

Boric acid dissolves pretty well in methanol, it dissolves less well
in ethanol (denatured alcohol, when it’s denatured). It’s
essentially insoluble in water, and somewhat in hot or boiling
water, which is part of why alcohol is used. I didn’t know it was
soluble in isopropyl acohol - doesn’t mean it’s not, it means I
didn’t know.

And yes, they are toxic and/or hazardous IF YOU INGEST THEM. You’re
not supposed to do that, you’re supposed to behave like an adult and
use good practices when handling ANY chemicals, from table salt to
sulfuric acid. A jar of methanol sitting on your bench top is just
sitting there, minding it’s own business. If you dip your finger into
it and then lick that finger, that would be bad (not SO bad, even)
but why on earth would you do that? It’s just stuff that needs to be
used with intellegence, and everything will be fine…


#18
A jar of methanol sitting on your bench top is just sitting there,
minding it's own business. 

It was my understanding that methanol fumes are quite toxic, that
it is not necessary to ingest it to be harmed. Am I wrong?

And, by the way, John, I am not “younger”, I DID take chemistry,
don’t consider it “evil”, actually liked it a lot, but have forgotten
most of it.

And, by the way, you didn’t actually answer my question.

Noel


#19

Denatured alcohol is simply methylated spirit in Australia —
mostly ethanol with a methanol and other nasties to make it
unpalatable to drink. Buy it at any supermarket

Jenny


#20
Time for a reality check here. I've found that much of our younger
generation didn't take chemistry, and it's a mystery (and often
evil) to them. 

This type of scientific ignorance is by no means typical of younger
generations, or limited to them. Just look at the age range of the
tea partiers and others trying to ignore the science of climate
change. Or the amazing percentage of the worlds population that still
gives credence to and believes in Astrology, while viewing with
bewilderment and suspicion any attempt to explain current
understandings of physics or cosmology. These span all age groups.
More difference, I think, between some cultures, than between age
groups.

What one might notice, though, is that a certain higher percentage
(than the general population) of the folks who gravitate to careers
in the arts, might also have done less well, or not been attracted to
the sciences. The percentage of jewelers who’ve never taken Chemistry
classes is no doubt higher than the percentage of engineers, and this
likely holds true for any age group you might choose.

Boric acid dissolves pretty well in methanol, it dissolves less
well in ethanol (denatured alcohol, when it's denatured). It's
essentially insoluble in water, 

Oh really? If this were true, John, the Boric acid in my Prips flux
would drop right back out of solution upon cooling. It does not do
so at all. Boric acid might not be as soluable as table salt, but it
does dissolve in water. Either that or what comes from my tap isn’t
water, or what’s in my jar of Boric acid powder, isn’t. And if you
go to the pharmacy and buy a jar of boric acid for use as an eye
wash, they don’t tell you to dissolve it in any alcohol. It’s a water
based solution, I promise you.