Hi The same caution applies to the beryllium in beryllium oxide heat spreaders. You find them in old RF transistors and some RF tubes.
Bob On Mar 10, 2010, at 6:45 PM, Bruce Griffiths wrote: > There's at least one known case where someone attempted to grind a beryllium > mirror substrate using conventional methods without proper control of dust > resulting in his death. > > Bruce > > Neville Michie wrote: >> Just in case anyone finds a beryllium brick somewhere and tries to use it: >> Beryllium is very very poisonous. >> cheers, >> Neville Michie >> >> On 11/03/2010, at 10:08 AM, Bruce Griffiths wrote: >> >>> p...@pseng.org.uk wrote: >>>> Looking at the specific heat of metals: >>>> http://www.engineeringtoolbox.com/specific-heat-metals-d_152.html >>>> Wouldn't Beryllium be better instead of aluminium? >>>> I could foresee a few problems though eg machining holes at home, never >>>> mind where to get a block from. >>>> >>>> Phil >>>> >>> Actually in this application minimising the volume of the metal block >>> rather than its weight is probably better so one should use specific >>> heat*density as a figure of merit. >>> >>> METAL Specific heat*density (W/J/cubic cm) >>> Aluminium 2.46 >>> >>> Beryllium 3.29 >>> >>> Copper 3.49 >>> >>> Silver 2.41 >>> >>> Iron 3.87 >>> >>> Thus copper and iron are better choices than Beryllium they also poses >>> fewer machining diffculties >>> >>> Bruce >>> >>> >>> _______________________________________________ >>> 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. > _______________________________________________ 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.
