[meteorite-list] Etching solution

From: MexicoDoug <mexicodoug_at_meteoritecentral.com>
Date: Thu, 26 Jan 2012 22:30:40 -0500 (EST)
Message-ID: <8CEAABB2DCB5078-494-42EAF_at_Webmail-m119.sysops.aol.com>

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
Received on Thu 26 Jan 2012 10:30:40 PM PST