[meteorite-list] Fw: Etching solution

From: Pete Pete <rsvp321_at_meteoritecentral.com>
Date: Fri, 27 Jan 2012 01:46:53 -0500
Message-ID: <BAY153-W8DF22A5066F190F070F7BF88E0_at_phx.gbl>

If I can add my experience to benefit others; many years ago, I used the instructions from the back of Norton's Rocks From Space book to do the nickel test on what later turned out to be a meteorwrong.

 

Full face shield, haz/mat gloves protecting up to my elbows, plastic body bib, a dual charcoal filter vapour respirator, and an 8 kg bucket of sodium bicarbonate standing by. And also wore a toque (Canadian, eh!)

I also made sure I had nothing behind me to trip me in case I had to make a hasty retreat.

 

Being a cautious noob, I did the whole procedure outside in an 8'x10' shed, open windows on three sides, a double door wide open, and a big fan set up at a window to exhaust the interior of the shed to the outside.

 

Not seeing results of the cherry red colour right away and since it was late, I turned the fan off and left the samples sitting in the solutions overnight .

 

Next morning with disappointment I saw the negative results and disposed of everything safely.

 

The next day after that I saw that everything metal in that shed started showing signs of corrosion, which continued until every metal surface within that shed was covered in rust!

I'm assuming that the corrosive fumes had filled the shed during the calm night regardless of the open windows and door, and had fun.

Think what that could do to your lungs!

 

Now I make sure that when doing anything with any type of acid, air is being mechanically vented and I don't leave anything unattended.

 

One further note of experience, when looking at meteorites under a stereoscope microscope, especially slices - even unpolished ones, if you wet them with isopropyl alcohol it will reveal maybe ten-fold the details.

I was using an old eye-glass cleaner atomizing sprayer filled with the alcohol and give the specimen a squirt when it started to dry while I was examining it.

 

I started waking up with severe headaches and it eventually dawned on me that I was poisoning myself by not venting the fumes away from me.

 

Now I do my ooo-ing and aaaaah-ing under a big ceiling fan, and have had no problems since.

 

Cheers,

Pete

 

 


 


> From: markig at westnet.com
> To: MexicoDoug at aim.com; meteoritesnorth at hotmail.ca; meteorite-list at meteoritecentral.com
> Date: Fri, 27 Jan 2012 00:32:10 -0500
> Subject: [meteorite-list] Fw: Etching solution
>
> Did a quick search on the internet. Read this tale from the Meteorite
> Association of Georgia regarding the hazards of mixing nitric acid and
> ethanol: http://www.meteoriteassociationofgeorgia.org/article-052007.htm.
>
> Mark
>
> Mark Grossman
> Meteorite Manuscripts
>
>
> ----- Original Message -----
> From: "Mark Grossman" <markig at westnet.com>
> To: <mexicodoug at aim.com>; <meteoritesnorth at hotmail.ca>;
> <Meteorite-list at meteoritecentral.com>
> Sent: Thursday, January 26, 2012 11:40 PM
> Subject: Re: [meteorite-list] Etching solution
>
>
> >I don't know all of the details of the etching process, but a word of
> >caution - mixing concentrated nitric acid with ethanol can result in an
> >explosion and a fire. I've witnessed the results of the reaction when
> >someone inadvertently mixed the two in a lab years ago.
> >
> > Mark
> >
> > Mark Grossman
> > Meteorite Manuscripts
> >
> > ----- Original Message -----
> > From: "MexicoDoug" <mexicodoug at aim.com>
> > To: <mexicodoug at aim.com>; <meteoritesnorth at hotmail.ca>;
> > <Meteorite-list at meteoritecentral.com>
> > Sent: Thursday, January 26, 2012 11:23 PM
> > Subject: Re: [meteorite-list] Etching solution
> >
> >
> >> PS - if you don't have a hood or other exhaust, the methyl alcohol could
> >> also be dangerous becasue the liver breaks it down into toxins and you
> >> will inhale some of it. That's another reason why I use ethanol in the
> >> oven, and frankly much more important a reason than saving a few pennies
> >> ;-) You can consider the residence time of the toxins in your system to
> >> be as long as a week, so if your are doing etxching all day long,and are
> >> using methanol nital you definitely need a very well ventilated place,
> >> and methanol is sneaky worthy of a CSI episode of an innocent who done it
> >> since the syptoms and critical second hit can be stealth and barely
> >> naseaous for the first.
> >>
> >> I know you didn't ask about methyl alcohol, but its good to see the 4
> >> common solcvent benefits/liabilities side by side, at least my take on
> >> it. Anyway, you can see why ethyl alcohol iis usually preferred. I just
> >> checkethe azeotrophes andisopropyl is only 2.3 C above ethanol mixtures
> >> so its ability to remove water would be very similar in the oven, the
> >> last thing to look up to decide theoretically approximating the
> >> penetrating ability as related to the surface tension of the alcohol
> >> (just a guess) what is the bestest alcohol would be to check the surface
> >> tension. I just did and all three alcohols are nearly 4 times that of
> >> water and within 5% o each other, so I would think that on penetrating
> >> ability they are probably all tied and would argue all factors considered
> >> ethanol is best since the worst you get is a standard hangover in
> >> standard use conditions, and to get a freak explosion from EtOH mixtures
> >> with acid is minimal compared to isopropyl.
> >>
> >> Ferric chloride of course doesn't have the toxicity not flammability, but
> >> it stains like heck and with proper respect for the reagents plus a
> >> little experience, like everything else the risks are minimized. That's
> >> another reason to start with dilute nitric which I highly recommend until
> >> you have the bugs worked out of the etching "assembly line", ie, method
> >> you find best for your work.
> >>
> >> Good luck,
> >>
> >> Kindest wshes
> >> Doug.
> >>
> >>
> >> -----Original Message-----
> >> From: MexicoDoug <mexicodoug at aim.com>
> >> To: meteoritesnorth <meteoritesnorth at hotmail.ca>; Meteorite-list
> >> <Meteorite-list at meteoritecentral.com>
> >> Sent: Thu, Jan 26, 2012 10:30 pm
> >> Subject: Re: [meteorite-list] Etching solution
> >>
> >>
> >> Craig,
> >> Let me add (the message actually got away before being finished as I
> >> write piecemeal and then send) that as far as etching it works fine,
> >> but if you look at the series of alcohols, methyl (bp = 65 C), ethyl
> >> (bp = 78 C) and isoproply alcohol (bp = 83 C), methyl alcohol
> >> (methanol) is by far the safest until you get a lot of experience
> >> working with these under a hood. "Ethyl nital" is mildly flammable in
> >> and Isopropyl nital is pretty dangerous since if can blow up in certain
> >> conditions that aren't difficult to arrange. Nothing to do with the
> >> etching results which are left to trial and error, but rather the
> >> safety which I should have mentioned.
> >>
> >> While all the alcohols work fine, keep in mind two of the factors you
> >> are working with are miscibility/penetrant ability and vapor pressure.
> >> Vapor pressure you can estimate by boiling point - lower bp is a higher
> >> vp. The higher vp the quicker it will evaporate out, so methanol would
> >> seem to have the advantage, thought it might form some azeotropes and
> >> stay in longer, as could the rest without looking this up (no time at
> >> the moment).
> >>
> >> To the series of three common alcohols you could just add water bp =
> >> 100 and consider it almost as a continuim and play with the you like
> >> which will influence drying time among other important parameters. I
> >> use methanol and later rinse with ethanol (cheaper for me), which is
> >> the reverse of good drying practice I would think, but half of the time
> >> I just use the diluted acid at 2 - 3 N.
> >>
> >> Hope that was a better answer, sorry for not finishing the first
> >> kindest wishes
> >> Doug
> >>
> >>
> >> -----Original Message-----
> >> From: Craig Moody <meteoritesnorth at hotmail.ca>
> >> To: mexicodoug <mexicodoug at aim.com>
> >> Sent: Thu, Jan 26, 2012 9:42 pm
> >> Subject: RE: [meteorite-list] Etching solution
> >>
> >>
> >> Much appreciated Doug, Thank you! I have lots of 99% around.
> >>
> >> Craig
> >> ______________________________________________
> >>
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Received on Fri 27 Jan 2012 01:46:53 AM PST