Small sphere or cylinder filled by a solvent

  1. how can I create a spheric glass ball or a closed cylinder containing a solvent as acetone or methanol?
    the ideal would be without air bubble inside and diameter in the range of 2-4 mm

    Last edited: Apr 29, 2013
  2. jcsd
  3. Danger

    Danger 9,663
    Gold Member

    Maybe you could get a professional glass-blower to do it for you. Your liquid could be used instead of air in the blowpipe (if it doesn't catch on fire or evaporate so violently that it blasts the molten glass to pieces).

    edit: Well, now that you've edited your question to include a cylinder as well as a sphere, there's nothing to it. Just buy some glass tubing, and some plate glass, then cut disks out of the plates to glue onto the ends of the tube.
    Last edited: May 11, 2013
  4. thank you for your reply.

    I surely have no experience in blowing / soldering small glass objects.
    can you address me where to buy such glass pipe or cylinders, or where I can learn how to do that?
    the solvent could be flammable or explosive so it could be necessary to reduce its evaporation by freezing into liquid nitrogen, but this is another history..

    thanks in advance
  5. Danger

    Danger 9,663
    Gold Member

    NO! :surprised
    That's just inviting an explosion.
    Let's back up a bit here. How old are you and what is your level of education? This is starting to seem dangerous.
  6. rollingstein

    rollingstein 636
    Gold Member

    Glass blowing and acetone seem a tad incompatible.
  7. Danger

    Danger 9,663
    Gold Member

    I had my doubts about it as well, but figured that it might be possible if the glob is being formed in the wet newspaper as opposed to in the flame.
  8. I am 45 y old and I am working with liquid nitrogen and helium (-270 K) from 20 years to do maintenance of superconductive magnets.
  9. Danger

    Danger 9,663
    Gold Member

    So do you plan to store these balls in liquid nitrogen until you're ready to use them? If you form them under those conditions, they will pretty much explode once they warm up.
    Last edited: May 14, 2013
  10. the idea was slowly filling the cilinder with acetone and refrigering the glass by using liquid nitrogen as external container; this is what one can do when a glass tube containing i.e. methanol has to be sealed for NMR experiments. The point here are the small dimensions... Today I will check with the phisical department if they can realize a small cyinder using PEK polymer.
  11. Danger

    Danger 9,663
    Gold Member

    Okay. Well then... check around with your colleagues as to feasibility. I very well could be wrong, but my gut feeling is that nitrogen is a bad idea.
  12. But, what is general idea? To do NMR experiments with various solutions? I would use long silica or ftorpolymer tube, connected to the pump and source of substances at one side. It would be cheaper for a set of experiments.
  13. Danger

    Danger 9,663
    Gold Member

    Experiments? :confused:

    I thought he was making party favours. :frown:
  14. Yes, the idea is generally related to NMR applications. In particolar I am looking for a way to improve the field stability in home-built probeheads for custom measures. I have to design a RF circuit around the small cylinder containing a non-viscous deuterated solvent as Acetone-d6
  15. rollingstein

    rollingstein 636
    Gold Member

    How about using a hollow thin bore cappilary needle to inject in pre-degassed acetone? The needle can easily be embedded in by the glassblower. Then either snap off the needle and seal off the exposed end by heat / electric arc etc. That should be an instantaneous weld for such a thin bore. That is if you are ok with the leftover needle segment.

    If not, post injection heat the needle segment externally and as soon as local glass melting occurs draw it out gently. Not easy.

    With 3mm sized spheres the fire risk is pretty small.
  16. It sounds interesting. But I do not think I have fully understood the steps to fill a capillary tube and weld the two ends without creating air bubbles...

    You have already successfully tested the method?

    Is there something to view/read on internet?
  17. rollingstein

    rollingstein 636
    Gold Member

    Not at all. I was brainstorming.

    It might be a total dud for all I know.
  18. 1. At the temperature of glass melting acetone will decompose. So, if you need to weld glass or especially bore capillary, you will need some gas medium, ie Ar.
    Or use some other shell material, in example ftorpolymer analogue of epoxy resin. To form acetone bubbles in the non-cured resin.

    2. solving probe substance in polar solvents like acetone may significantly widen spectrum via shifting energy levels.
    May be better to use pure gas to reduce intermolecular interaction?

    3. If those probeheads will be anyway cooled by liquid nitrogen, why not use SQUID instead?
    Last edited: May 18, 2013
  19. That's why I thought to use liquid nitrogen to cool down the cylinder containing the Acetone when the glass has to be sealed.

    In the cylinder there are no other mixed solutions/samples other than Acetone-d6, the source of deuterium for the 2H detector.

    The probes will work at room temperature and will use dry air rather than liquid N2.
  20. Today I have got a first prototype of such a cylinder in made PVC.
    Going to test the sealing...
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