[meteorite-list] Fw: Etching solution

From: Mark Grossman <markig_at_meteoritecentral.com>
Date: Fri, 27 Jan 2012 00:32:10 -0500
Message-ID: <A36931C711AD4D1A82A1CFD26EE0C6B4_at_QED>

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
>> ______________________________________________
>>
>> Visit the Archives at
>> http://www.meteoritecentral.com/mailing-list-archives.html
>> Meteorite-list mailing list
>> Meteorite-list at meteoritecentral.com
>> http://six.pairlist.net/mailman/listinfo/meteorite-list
>>
>> ______________________________________________
>>
>> Visit the Archives at
>> http://www.meteoritecentral.com/mailing-list-archives.html
>> Meteorite-list mailing list
>> Meteorite-list at meteoritecentral.com
>> http://six.pairlist.net/mailman/listinfo/meteorite-list
>
> ______________________________________________
>
> Visit the Archives at
> http://www.meteoritecentral.com/mailing-list-archives.html
> Meteorite-list mailing list
> Meteorite-list at meteoritecentral.com
> http://six.pairlist.net/mailman/listinfo/meteorite-list
Received on Fri 27 Jan 2012 12:32:10 AM PST