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From: John De Armond
Subject: Re: Acetone&kilns
Date: 2000/09/21
Message-ID: <>

Brad Shute wrote:
> I like to use isopropyl (rubbing) alcohol. See my website at:

I guess you feel that isopropyl alcohol is safer than acetone, eh?
Well, let's see.  Here are some properties for the two chemicals:

                      Isopropanol      Acetone
Formula               C3H8O            C3H6O
Boiling point         82 deg c         56 deg c
Vapor density (rel.)  2.1              2.0
Flash point           12 deg c        -20 deg c
Ignition temperature  750 deg          465 deg c
Explosive range       2.5-12%          2.6-13%
Toxicity                (3)              (3)

Let's see what these mean.  We see that the toxicity rating for both
is the same.  No safety advantage there.  Very important to this
topic, we see that the range of mixtures in air that will explode
are essentially the same.  Coupled with that is the almost identical
vapor density.  Both are about twice as heavy as air which means the
vapors would lay around in our mythical kiln just waiting to
explode.  Acetone has a somewhat lower boiling point but not enough
to matter much as far as safety goes.  And it has the edge on
ignition temperature but again, it doesn't matter because our fires
and kilns get hot enough to ignite either substance if they managed
to collect in the kiln.  Of course, the water in rubbing alcohol
will slow its evaporation down some but not enough to matter.

So we have two similar chemicals, one of which Brad screeches dire
warnings of disaster and the other he recommends.  What's the
difference?  Acetone is an aromatic substance and alcohol isn't.  In
other words, acetone has a strong odor which makes the layperson
"feel" that it is more flammable.  I guess that in this
touchy-squeezie world of political correctness, we're now doing
feelings-based science, eh?  Not!

Bottom line with both of these solvents is that they are perfectly
safe to use in the small quantities that a glass artist would
typically use them.  Of the two, I'd much rather use acetone, as
isopropanol is a rather poor grease solvent, especially when mixed
with water as in rubbing alcohol.  Pure Ethanol works much better.
(We found that ethanol, AKA Everpure pure grain alcohol straight
from the liquor store was probably the best solvent to clean very
high impedance nuclear electrometer circuits where a single
fingerprint will disrupt the circuit's operation.)  My preferred
wash for chemically cleaning glass is a detergent wash with Alconex
(available from Lab Safety Supply online), followed by a caustic
soda wash to remove any residual organics, followed by nitric acid
to remove any trace metals.  Not necessary for fusing, of course,
but very necessary for mirror making or thin film work.  For fusing,
the Alconex wash is sufficient.

> As far as John DeArmond goes, it is obvious that Mike Aurelius is right
> about him.

Coming from either you or "Spammer Mike", I consider that the
supreme compliment.

> He certainly isn't worth wasting any
> more time responding to. Although I will say that the years he says he
> spent in the nuclear industry certainly explain a lot about his safety
> attitude.

Yes, perfection is an achievement.  When you can work your little
glass hobby around to be as safe as nuclear power (no deaths, no
nuclear-related injuries, no civilian radiation exposures, no
material environmental impact), you'll have something to brag about.

> I'm sure the industry was ecstatic to have him "as Bradley County's
> radiological safety chief".

Judging by the amount of materials I've gotten donated to the
program, they must be ecstatic.  Our program was the first in the
nation to score a perfect score from the NRC on our emergency plan
and its execution.  Stop by sometime, I'll take you on a tour of the
EOC and show you the certificates.

>I wonder who bought out his lab and made him rich?

Lost track after a couple of subsequent sales but I think Bechtel
ended up with the company.

> I can also imagine the sign in his diner - "Plutonium, the
> OTHER, other white meat". Eat up and enjoy, folks.

Actually the sign is "Nuke 'em til they glow, then shoot 'em in the
dark", an inside dark joke from Y-12.  People get a kick out of that
one.  Oh, and Pu in air is a dark gray and not white.  In the glove
box in argon, it has a silvery, almost luminous iridescence unique
to the metal.  Of course, I wouldn't expect you to know that.

> The question I was responding to, from Michelle Blank, in which she was
> specifically seeking comments about kiln explosions and acetone: "I've
> been cleaning glass prior to fusing with acetone. The thought occurred
> to me that this might cause a safety hazard ie:the fumes creating an
> explosion in the kiln? Just a thought......Any comments?"

I'm still curious as to your scenario where that could occur.  One
puts glass to be fused in a cold kiln and gradually heats it up.
Obviously even if the piece were to be put into the kiln wet with
acetone, it would be long gone from air expansion and convection
before the kiln gets hot enough to ignite the vapors.

I suppose that with a perfectly air tight kiln under just the right
conditions there is a theoretical possibility of ignition.  If you'd
stated it that way, I'd have had no problem with it.  But to
screech:  (quoted exactly so you can't accuse me of changing your

> > Aarrrggghhhhhh, NOOOOOO!
> >
> > Under the right circumstances both acetone and alcohol can be
> > EXTREMELY dangerous. I PERSONALLY know of several instances where
> > explosions were caused - and people got hurt, some VERY seriously -
> > after heating pieces cleaned with one or the other. In the research
> > lab the first thing we asked if someone brought in a piece for repair
> > was, "have you tried to clean it with either acetone or alcohol?" If
> > the answer was "yes", we then recleaned it ourselves making sure there
> > was no residue. If the answer was "no" we did the same thing anyway,
> > just to be sure.

Is chemophobic wolf crying.  (Do you REALLY re-clean a clean piece
of glassware before repairing it as opposed to giving it a quick
nitrogen purge if it fails the sniff test?  Wow, what a waste of

And how does "Aarrrggghhhhhh, NOOOOOO!" for acetone reconcile with
"I like to use isopropyl (rubbing) alcohol" for isopropanol,
considering the similarity of the two substances?

And if "Aarrrrghhhhhhh, NOOOOOOOO!!!!!" is the appropriate response
to this very slight hazard, then what expression of alarm would you
use when warning about a legitimately hazardous situation.  Perhaps,
say, the novice use of the cyanide process for noble metal plating.
That's the problem with crying wolf - once you use up all the
alarmist words on slight hazards, there are no words left to
properly express real hazards.

> I'm not going to waste any more time on this thread. The information is
> there for the people who are smart enough to use it wisely.

Typical response of someone who's talked himself into a corner.  Run
and hide.  For some reason, I just don't quite believe you.

So Brad, you and your minions have slung insults, baselessly
disparaged my professional reputation, tried to cover your lack of
knowledge by quoting second hand comments from someone not involved
in this debate (and who could take anyone seriously who would offer
an allegedly professional opinion from afar?)  What you haven't done
is toss in even a shred of fact.  One can only wonder what your next
trick will be.  BTW, did you REALLY believe that stuff about getting
HF on the hand could be fatal?  Really?  Wow!


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