Dear all

Here, in Granada (Spain), we have been working for more than 10 years
warming our kel-F traps with a heat gun without any broken, ... better said,
only one broken due to much amount of exausted reagent into the kelF trap
and when temperature went up ... Now we use to remove our exausted trap once
a week. Our traps are internal V-shape.

Rafa
>Dear Peter and others interested,
>
>As others have already mentioned, I believe, it is usually preferable to
>have the bottom cut of the Kel-F finger to be of a different shape than the
>standard V- or square-shape of the cutting tool. A spherical end is reputed
>to produce less stresses within the kel-F tube.
>
>If Peter would give is optimal cooling mixture for BrF5 distillation, I am
>sure that several of us will be interested. I guess it is so simple to use
>LN that you do not think of a lower temperature coolant.
>
>As for thawing, I have been warming the Kel-F tube slowly with a heat gun.
>In partice, we place the heat gun about 2 feet below the tube and blow warm
>air arond the length of the tube. This should be less stressing than the
>water bath... but still must introduce temperature gradients (and
>stresses?) into the tube. My experience is for a period of 4 years without
>noticeable deterioration, but Peter's adventure is well noted! Anybody else
>experienced with the warm air cooling that could give feedback?
>
>Dr. Georges Beaudoin
>Professeur
>Département de géologie et de génie géologique
>Université Laval
>Québec, Québec
>Canada
>G1K 7P4
>tel.: 1-418-656-3141
>fax.: 1-418-656-7339
>
Rafael Nunez Gomez
Laboratorio Isotopos Estables
Estacion Experimental del Zaidin (C.S.I.C.)
Profesor Albareda 1, 18008
Granada, Spain
Tf 34 58 121011
Fax 34 58 129600
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http://www.eez.csic.es/~isotopos/