They look like this.

blue rubber butyl stoppers

We have to do a lot of gas sampling and these are really difficult to assemble. I've been scouring the internet for advice but there are none. Do you have experience with these? Have you found a good way to put them on that doesn't destroy hands, hearts, and dreams?

To clarify, the hard part is putting the blue stoppers in the tubes in the first place. Once they go thoroughly in, we can crimp them with our hand crimping tool. Since the time I posted this, I find a (little) better luck using a piece of cloth / putting the cap and the glass vial between a vice. With too much pressure, I actually broke a vial and glass shattered everywhere. The best way to put them in is with a twist, but that usually comes with an expense of bruised hands after extensive use.

Wish I had a camera on me, but they look somewhat like this:

enter image description here

  • $\begingroup$ does application of some lubricating agent to the tops help or would that interfere with/contaminate with your gas mixture in the bottles? $\endgroup$ Commented Aug 12, 2014 at 22:12
  • $\begingroup$ Alternatively you can try heating the blue top perhaps in warm/hot water and see if that helps! $\endgroup$ Commented Aug 12, 2014 at 22:35
  • $\begingroup$ Well these will be gas samples, so I'm not sure, but we are trying to stay away from too much contaminates. Thanks for the idea though! It should make more sense to heat up the bottles first, and we may give that a shot. $\endgroup$
    – dot_zero
    Commented Aug 14, 2014 at 0:49

1 Answer 1


From what I can tell from this machine (https://www.youtube.com/watch?v=TwRtsAG5Oy4), the blue caps are put on the bottles first, then a loose version of the aluminium neck seals are put around the top of the capsule, which is then pressed in the machine to seal the lid hence if you use many gas sampling techniques, it might worth investing in purchasing a similar machine/technology to seal your samples, which would be the most efficient in the long run.

EDIT: as pointed by @user137 there are also hand crimping tools, which you can use, which are considerably cheaper, which as @user137 pointed out, can be found here

  • 1
    $\begingroup$ That looks expensive, you might be able to get away with a hand crimping tool. This site has a wide variety : vialcrimpers.com $\endgroup$
    – user137
    Commented Aug 12, 2014 at 15:48

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