[meteorite-list] Etching solution
From: MexicoDoug <mexicodoug_at_meteoritecentral.com>
Date: Fri, 27 Jan 2012 03:11:05 -0500 (EST) Message-ID: <8CEAAE259F66001-F84-42A77_at_webmail-d019.sysops.aol.com> "explosive" Definitely caution when playing around with corrosives is of the first order...that said, sure, ethanol is a racing car engine fuel and under the right conditions can combust; But people drink it even straight... Many things we do have risks associated with them some very serious and definitely we must respect all reagents especially corrosives like nitric acid. For example, many people enjoy fireworks. Yet, fireworks are explosive and dangerous if you put them near sparks or heat,or try to light them with a charcoal grill. And obviously gasoline combusts too yet mechanics and Dads everywhere use it to clean hands and metal parts and also have arc welders nearby. Or sulfuric acid inside a car battery - don't get it on your bikini when working on the car! If you are going to use anything, it needs to be done with respect and a quick read of the MSDS of whatever chemicals you are using... (and don't trust everything you read on a discussion l;ist posted at 3 AM) It is not a good idea to have concentrated nitric acid and ignore the label, for example and my heart goes out to Anita on that. Depends the kind of person you are. When I make my smoothie in the morning I use fresh cherries as one of 18-20 ingredients and a preparation that takes an hour. It's life threatening if I accidentally put a pit in my blender (which can easily liquify meteorites, it's so powerful) due to the specialized needs of a family member who cannot eat. So I double count the cherries first, count the pits as I punch them out, and then count them once again when I dispose of them. No shortcuts, All common sense! Bart Simpson's pet python once made nital in an episode of The Simpsons, which is amusing if you haven't had a bad experience you can't laugh about.... I think the writers were Caltech rejects that had to go to MIT and have to do this to humor themselves, this wasn't the only snarky chemistry episode. (episode: Stop or my Dog will Shoot!) Here's the link: http://video.i.ua/user/810302/8185/35583/ it take a little time to stream, but once ready the scene is at the 17:49 minute:seconds mark. ... and that' why in my summary which I did much too quickly to be complete, I suggest that you use water, that is to say, NitH20,. or as it's commonly known just dilute Nitric Acid, rather tha alcohols to develop your method. Nothing wrong with water, it is really getting a bum wrap and it is GRAS ;-) It is what everyone that is using FeCl3 is using as a diluent, too. For the HNO3 the 3.0 N concentration works best for me. Absolutely no need to buy concentrated acid and you can avoid all the issues of what to add to what and no need for Hazmet backup. You can buy it already diluted, get the same benefit of a nitric acid etch (alcohol doesn't etch, it's only a carrier and diluent). Just crank up the oven to the higher end of a safe drying temperature. That's the only real benefit of alcohol in my opinion - it allows a cooler drying which can povide a nicer (lower oxdation residue on the virgin etched surface, but now we are staerting rally to split hairs...IMO. Speaking of diluents, there's no reason nital (alcohol) is special as a diluent. Besides water, I'm suspecting Nitric + acetone (Nitkeytone ?) and any number of other solvents would work fine if not be hiding a secret for even a better etching solution. Sure acetone is flammable and can give you the willies too, you can't win but that doesn't stop women who understand the chemical they use from putting it on their fingernails ;-) granted not with acid, though I bet some do inadvertantly mix it with salycilic acid solution when disolving excess skin ;-), which if not used properly could chemically remove a lot of flesh ... Kindest wishes Doug -----Original Message----- From: Mark Grossman <markig at westnet.com> To: MexicoDoug <MexicoDoug at aim.com>; meteoritesnorth <meteoritesnorth at hotmail.ca>; meteorite-list <meteorite-list at meteoritecentral.com> Sent: Fri, Jan 27, 2012 12:32 am Subject: Fw: [meteorite-list] 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 >> ______________________________________________ >> >> 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 03:11:05 AM PST |
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