[meteorite-list] Water cutting question

From: Ed Deckert <edeckert_at_meteoritecentral.com>
Date: Tue, 20 Nov 2012 17:45:58 -0500
Message-ID: <BDD68F62CA214C22A1D39D701E4F7A7E_at_MAINPC>

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" <mikestang at gmail.com>
To: "Pete Pete" <rsvp321 at hotmail.com>
Cc: "meteoritelist meteoritelist" <meteorite-list at 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 <rsvp321 at 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: mikestang at gmail.com
>>> Date: Tue, 20 Nov 2012 11:17:37 -0800
>>> To: raremeteorites at yahoo.com
>>> CC: meteorite-list at 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 <raremeteorites at 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 <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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Received on Tue 20 Nov 2012 05:45:58 PM PST