[meteorite-list] Water cutting question

[Adam Hupe]

Who knows what chemicals lurk in tap water?  By purifying it, you are removing the unknowns.  I have 
seen, for lack of a better term, Lawrencite disease creep up, especially with tap water that contains chlorine which seems to accelerate the 
problem.  I have had no issues cutting with purified water as long as 
the contact time has been minimized.  I guess purifying it could make 
the water more acidic but I also monitor the PH level and have not seen 
much of a difference.

Other alternative coolants such as  mineral oil, pure ethyl alcohol or 
kerosine do not appeal to me anymore, mainly due to fumes, ignition or 
the smell left in the specimens. 


Adam




________________________________
From: Carl Agee <agee at unm.edu>
To: meteoritelist meteoritelist <meteorite-list at meteoritecentral.com> 
Sent: Tuesday, November 20, 2012 9:35 AM
Subject: [meteorite-list] Water cutting question

I have been following the thread on cutting irons in water. My
question is, why distilled or purified water rather than tap water? I
was under the impression that purified water, i.e. ultrapure water, is
much more corrosive than mineralized water like spring water or tap
water. In fact, ultrapure water is so corrosive it is often used in
clean labs as a cleaning medium for surfaces. Also, the pharmaceutical
industry no longer uses stainless steel tubing for ultrapure water
because of corrosion -- they use Teflon or polyethylene  instead I
believe.  Wouldn't pure water be worse on iron oxidation than
"mineral" water? I can understand using pure water to cut down on
trace element contamination for geochemical srtudies, especially on
stones, but I don't see how this helps for keeping irons from rusting.
Also, while we are at it, what is the best blade for cutting irons?

Thanks,

Carl Agee
--
Carl B. Agee
Director and Curator, Institute of Meteoritics
Professor, Earth and Planetary Sciences
MSC03 2050
University of New Mexico
Albuquerque NM 87131-1126

Tel: (505) 750-7172
Fax: (505) 277-3577
Email: agee at unm.edu
http://meteorite.unm.edu/people/carl_agee/
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