You can't be serious. Ammonia gas or liquid is dangerous. You can buy calibrated RTDs or rent a quartz thermometer and stay alive.
YMMV, -John =============== > Hi > > If the intent is to come up with a triple point cell to calibrate your > thermometer, acetone's triple point (at 178.5K) is a bit low. I still > think I'd go with ammonia. > > Bob > > On Jan 26, 2013, at 2:51 PM, Graham / KE9H <time...@austin.rr.com> wrote: > >> On 1/26/2013 1:29 PM, Paul Amaranth wrote: >>>> Message: 4 >>>> Date: Sat, 26 Jan 2013 16:28:19 +0100 >>>> From: Fabio Eboli <fabi...@quipo.it> >>>> To: Discussion of precise time and frequency measurement >>>> <time-nuts@febo.com> >>>> Subject: Re: [time-nuts] OT, looking for a good science forum >>>> Message-ID: <5ef3f142b075fcab38182666a4e50...@quipo.it> >>>> Content-Type: text/plain; charset=UTF-8; format=flowed >>>> >>>> Il 2013-01-26 14:58 Bob Camp ha scritto: >>>>> Hi >>>>> >>>>> Platinum RTD's are a pretty good bet for -80C, they hold up well down >>>>> there. For calibration, ammonia and acetylene both have triple points >>>>> in the vicinity. I'd probably try ammonia first, but not for any good >>>> Doesn't acetylene have a bad habit of dissociate when pure liquid? >>>> >>>> Fabio. >>>> >>> Yes, it's normally stored disolved in acetone. It also spontaneously >>> dissociates >>> if pressures exceed 15 psig or 30 psi absolute. That could put a real >>> damper on your day. >>> >>> >> Just pure acetone works well at dry ice temperatures. We used crushed >> dry ice >> in acetone as an alternative when the liquid nitrogen truck was late >> making its delivery >> for the cryro lab. >> >> --- Graham / KE9H >> >> == >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.