Hi Michael,
Is there a method to calculate how long to leave a specific volume of water
at a specific vacuum (inches Hg) to ensure that it is degassed?
Thanks,
Ed
----- Original Message -----
From: "Michael Mulgrew" <mikest...@gmail.com>
To: "Pete Pete" <rsvp...@hotmail.com>
Cc: "meteoritelist meteoritelist" <meteorite-list@meteoritecentral.com>
Sent: Tuesday, November 20, 2012 5:08 PM
Subject: Re: [meteorite-list] Water cutting question
Pete and list,
Unfortunately the method you use does not effectively de-gas water, as
exposure to the atmosphere will allow atmospheric gasses to continue
to dissolve into solution; it is the atmospheric gasses that cause
water to be corrosive. To de-gas water you can:
- Boil it
- Sonicate under vacuum
- Use a vacuum degasser
- Bubble He through it
- Etc.
But unless you store your degassed water in an air-tight container
gasses will begin to dissolve back into solution almost immediately.
Michael in so. Cal.
On Tue, Nov 20, 2012 at 1:47 PM, Pete Pete <rsvp...@hotmail.com> wrote:
I do!
I fill all my old distilled four litre jugs with tap water and let them
sit with the caps off for about seven days.
A chemist buddy of mine said it takes about 24 hours for any chlorine and
other gasses to dissipate, but with the narrow neck and relatively small
cap opening, to be prudent, after a couple of days I give it each jug a
shake and leave it again for a few more.
Cheers,
Pete
From: mikest...@gmail.com
Date: Tue, 20 Nov 2012 11:17:37 -0800
To: raremeteori...@yahoo.com
CC: meteorite-list@meteoritecentral.com
Subject: Re: [meteorite-list] Water cutting question
Adam, Mike, Carl, and list:
The main constituents in "pure" water that cause corrosion are
dissolved gasses. Does anyone de-gas their cutting water?
Michael in so. Cal.
On Tue, Nov 20, 2012 at 10:43 AM, Adam Hupe <raremeteori...@yahoo.com>
wrote:
>
>
> 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 <a...@unm.edu>
> To: meteoritelist meteoritelist <meteorite-list@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: a...@unm.edu
> http://meteorite.unm.edu/people/carl_agee/
> ______________________________________________
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