[meteorite-list] Water cutting question

From: Michael Mulgrew <mikestang_at_meteoritecentral.com>
Date: Tue, 20 Nov 2012 15:23:09 -0800
Message-ID: <CAMseTy0GUmJCeNVPx0A24Y7VjBgBJiUonHsbMYPij0H7BkBbvQ_at_mail.gmail.com>

Ed and list,

I do not know of an exact way to calculate, but a few minutes at
around 29 inches Hg of vacuum (sea level), especially on a hot plate
and with a little aggitation, will remove about all of the dissolved
gasses.

Michael in so. Cal.

On Tue, Nov 20, 2012 at 2:45 PM, Ed Deckert <edeckert at triad.rr.com> wrote:
>
> 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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>>
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>
Received on Tue 20 Nov 2012 06:23:09 PM PST


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