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 <edeck...@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" <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/ >>>> > ______________________________________________ >>>> > >>>> > Visit the Archives at http://www.meteorite-list-archives.com >>>> > Meteorite-list mailing list >>>> > Meteorite-list@meteoritecentral.com >>>> > http://six.pairlist.net/mailman/listinfo/meteorite-list >>>> > ______________________________________________ >>>> > >>>> > Visit the Archives at http://www.meteorite-list-archives.com >>>> > Meteorite-list mailing list >>>> > Meteorite-list@meteoritecentral.com >>>> > http://six.pairlist.net/mailman/listinfo/meteorite-list >>>> ______________________________________________ >>>> >>>> Visit the Archives at http://www.meteorite-list-archives.com >>>> Meteorite-list mailing list >>>> Meteorite-list@meteoritecentral.com >>>> http://six.pairlist.net/mailman/listinfo/meteorite-list >> >> ______________________________________________ >> >> Visit the Archives at http://www.meteorite-list-archives.com >> Meteorite-list mailing list >> Meteorite-list@meteoritecentral.com >> http://six.pairlist.net/mailman/listinfo/meteorite-list >> > ______________________________________________ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
