Hi all,
I have to be honest, I have no idea what material the amber-colored tubing
we use is, natural rubber?, latex ? All I know is that it does not crack,
fracture, fray, or explode and we have been using it for years. It is nice
and thick-walled, flexible, and fits snugly on both our magnets (old with
narrower port and new with wider port) without adjustment. I position the
transfer dewar close to the magnet for filling and thus only a short length
of tubing is required, obviating the need for insulation and, since there is
little weight, the tubing mostly does not crimp at the port (occasionally may
have to hold it for a bit till it is cool to preclude crimping). On the exit
side I use a long piece of tubing, both to stop liquid nitrogen spilling
onto the magnet and to collect the expelled liquid nitrogen in a styrofoam
box when the magnet has filled up. With this extra weight, to preclude
crimping at the exit port, I use a short piece of 90 degree angled PVC
piping that is available at any hardware store that the tubing is threaded
through.
Regards,
K. Klika
________________________________________
> From: main_at_ammrl.groups.io on behalf of Jan Lang via groups.io
> Sent: 05 January 2026 18:37:07
> To: main_at_ammrl.groups.io
> Subject: Re: [AMMRL] Real Natural Rubber Tubing
Hello,
we are using reinforced PVC tube (softenned PVC, both the inner and outer parts)
for drinking water (a kind of a „garden hose“ as well) like this
https://www.gumex.cz/h/1125-hadice-na-pitnou-vodu-a-tekute-pozivatiny-01283?Filter=True
either 10/14mm diam. or 16/22 diam. (inner/outer) for different magnets.
It is rigid and brittle when cold. It has to warm up (either naturally or with
a heat gun) to become flexible again.
It breaks once upon a time (in several monts/a year), so we cut a new piece. At
a price of ~ 1USD/m it is much cheaper than the Bruker set. It does not disintegrate
in an „explosive“ manner into many small pieces.
The Bruker PTFE coversion piece and a chunk of silicon is useful when using
the thinner hose for two magnets with different inlet diameters. The silicon
chunk can be bought separately too.
Best regards,
Jan
> From: main_at_ammrl.groups.io On Behalf Of Michael Groves via groups.io
> Sent: Monday, January 5, 2026 4:44 PM
> To: main_at_ammrl.groups.io
> Subject: Re: [AMMRL] Real Natural Rubber Tubing
I'll second the PTFE. It stays nice and flexible with LN2 flowing through
it. Bruker sells a kit
https://store.bruker.com/products/nitrogen-refill-set
with a chunk of silicone tubing on each end and the PTFE in the middle. And
an adapter for the larger fill ports on the newer Bruker magnets. People
definitely have to replace the silicone tubing occasionally but that PTFE
stuff will last a long time.
Cheers,
Mike
On Monday, January 5, 2026 at 08:23:33 AM MST, Plant,Daniel via groups.io wrote:
A friend of mine uses PTFE...haven't tried it but it sounds good...for fills.
(wasn't the original poster asking about N2 vent tubing...?)
....Yea we stopped using the rubber connections because it eventually fractures
and can shoot pieces out when it does. We have been using bellowed PTFE for
a few years now. The lower end of the temperature range is -450F. It is a
little costly but worth it. They last a few years but will finally start
leaking on the magnet side from strain. I buy a 6 or 10 foot section and
then add a 1 foot section to the end so that it can be replaced if it fails
preserving the lengthy piece. The ID of the of the tube in the link (.47”)
snuggly fits most of our magnets nitrogen turrets so no need for the rubber connector.
https://www.mcmaster.com/51155K68/
________________________________
> From: main_at_ammrl.groups.io on behalf of Cathy Clewett via groups.io
> Sent: Monday, January 5, 2026 9:21 AM
> To: main_at_ammrl.groups.io
> Subject: Re: [AMMRL] Real Natural Rubber Tubing
Hi all,
The pipe insulation may work well for the purpose described, and be aware
that some of this material is magnetic. Way back another lifetime ago, we
used to use it to insulate heating air going to our probes. We found that
the material was magnetic and affected our shims. It also has a tendency to
pill and shred with repeated use. I would suggest being careful with it
around magnets.
Cheers!
Catherine F. M. Clewett, Ph.D.
Asst. Director Magnetic Resonance
Chemistry Instrumentation Center
University of Wisconsin Madison, Department of Chemistry
1101 University Ave Room 2201c, Madison, WI 53706
clewett_at_wisc.edu, (608)262-8196,
https://pbcic.chem.wisc.edu
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Received on Mon Jan 05 2026 - 12:36:30 MST