Hi David!

I have been using 0.010" thick Kel-F sheets for years for carbonates and
water samples with no problems with our Optima-MultiPrep.  We found that
the 0.005" thick sheets were indeed too thin.  We had no problem with wads
of Kel-F being pushed into the vials, but, as you found, the entire disk
would often be pushed into the vials.

I order my Kel-F sheets from AIN Plastics in Mount Vernon, New York:

Kel-F is also carried by San Diego Plastics in San Diego, California:

Let me know if you have any more questions.


David Wheeler wrote:
> I am about to order some new Kel-F sheets to make the septa used to seal
> the Wheaton 1mL vials used on our Micromass multiprep, for doing
> carbonates and oxygen in water.
> In this setup the needle is pushed through the blue silicone septum and
> the Kel-F disc.  I am concerned about the number of times the needle,
> instead of punching a neat hole through the Kel-F, actually punches a
> wad into the vial.  When I take the cap off the vial there is an annulus
> of Kel-F between the rim of the vial and the silicone septa and a disc
> of Kel-F inside the vial.  (I hope that makes sense.)  This used to
> happen occassionally with carbonates, where the needle is large and
> pretty blunt, but now it is even happening with the smaller water needle.
> We have been using sheets 0.005" thick.  I'm wondering whether this is a
> dud batch of Kel-F or is the Kel-F too thin.  What thichness do other
> labs use?  I'm also interested in which suppliers are the best.  Post
> comments about suppliers off-list if you prefer.
> cheers,
> David
> --
> 內躬偕爻內躬內躬偕爻內躬內躬偕爻內躬內躬偕爻內躬內躬偕爻內躬內躬偕爻
> David Wheeler
> Professional Officer
> Geochemistry Laboratory
> School of Earth and Environmental Sciences
> University of Wollongong,
> Wollongong, 2522, NSW
> Australia
> Phone   02 4221 4586 (office)
> 	02 4226 5903 (lab)
> Fax 	02 4221 4250
> E-mail	[log in to unmask]
> 'These days, if a scientist can't get
>  an answer by isotope analysis, he ain't hep'
>                        - Isaac Asimov, 1959
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