[meteorite-list] ACID FOR ETCHING: QUESTION

[mark ford]

Hi Charles,

 

The strength of the ferric Chloride solution is quite important, it
needs to be a reasonably concentrated solution, (too slow and it doesn't
give such good results, because the reaction slows after a few minutes,
presumably because the surface becomes less 'clean' and doesn't react as
quickly, so you need to etch it within a minute or so.).

 

 Personally, I have directly compared Nitric Acid etching to Ferric
Chloride etching, and found Ferric to be noticeably superior (This is
consistent with (I think) 'O' Richard Norton's article in Meteorite
magazine some years back, he also discussed tint etching, which uses
various chemicals to bring out features by coloring them.

 

No too falls are the same however and I have not tried it on anything
other that Gibeon, Campo, Sikhote, Brahin (and a couple of others). I
expect the differing Nickel contents will produce varying results with
both methods, experimentation is the best policy! ...

 

Best

Mark

 

 

  _____  

From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of
Charles Viau
Sent: 25 November 2006 04:51
To: mark ford; meteorite-list at meteoritecentral.com
Subject: Re: [meteorite-list] ACID FOR ETCHING: QUESTION

 

While Ferric Chloride is safer, it is much slower... and it seems (to me
anyway) that the etched definition is much lower....

 

I have found a good source for small quantities of nitric acid to be
jewelers, especially those that plate gold.

They mix hydrochloric with nitric to make aqua regia, an acid powerful
enough to dissolve gold. Very dangerous stuff and certainly not an acid
that you would ever use on a meteorite, unless you want to see it
disappear... however many will sell you a small amount of nitric if you
ask. Again, they use the pure stuff so be real careful... take it home
wrapped in lots of paper in a box.  Dilute it!  Typical is a 5% Nitric
solution using 100% denatured ethyl alcohol  (not the isopropyl type in
water) or 1 part pure nitric in 19 parts alcohol.     

Standard chem. 101 safety statement : Add acid into alcohol!, not
alcohol into acid! , wear goggles, use latex gloves and do it in the
garage, not the house...

 

CharlyV

 

  _____  

From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of mark
ford
Sent: Thursday, November 16, 2006 10:25 AM
To: meteorite-list at meteoritecentral.com
Subject: Re: [meteorite-list] ACID FOR ETCHING: QUESTION

 

Try Ferric Chloride much better and safer.  - Available from electronics
stores

 

 

 

  _____  

From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of
jwb7772 at netzero.net
Sent: 16 November 2006 01:45
To: meteorite-list at meteoritecentral.com
Subject: [meteorite-list] ACID FOR ETCHING: QUESTION

 

Hi to all list members!

     It has been a long time since I have needed a new bottle of nitric
acid.  So long that the last time I bought a bottle, it was at a drug
store.  Really!  Short of going 25 miles to a collage chem store, where
would be the best place to get a bottle of acid?  No one around my town
has any!  Any help would be appreciated.  Thanks,  Jim Balister


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