I take back what I said about ampouling.

Sealing ampoules turns out to be nontrivial, especially when the contents of the ampoules are under vacuum.

The theory is pretty straightforward. Heat the glass at the desired sealing area, rotating slowly. This time, heat a bit more - the glass will melt and bend "inwards". Now, when I was watching other people do this, the glass melts in a nice ring and a few repeated twists will seal the ampoule. A few more twists will free the ampoule, and then just tidy up the sealed end with a bit more heat.

When I do it, the glass softens quickly and drastically. It's still possible to seal the tube when this happens - when all the glass in the heated area has more-or-less merged, twist the ampoule until the closed end comes off. Then just tidy up the end as before.

It turns out that it's really easy to break the tubing by heating the glass too much. The nice thing about evacuated ampoules is that, if you break the vacuum, it makes a loud popping sound. So yea. If you break an ampoule, everyone within hearing range will know it.

And let's just say that I've managed to break every ampoule handed to me today during sealing. Yay me. Fortunately, the reagents in question can survive in air for a reasonable amount of time (during which the sample gets re-evacuated and re-sealed by my supervisor), but we'll see what happens during characterization.

I'm not sure why it's so hard to seal ampoules without breaking the vacuum. One complication is that the ampoule comes with the vacuum line attachment (I'm not sure what the glass connection to the Schlenk line is called). The attachment is a bit unwieldy, so it's a bit harder to turn the glass tubing evenly. Making glass ampoules is much easier since the first step (pulling tubing apart) gives rise to a nice narrow opening that's easy to close, whereas in sealing ampoules there's no pulling step, so the opening is relatively large and hard to close. Other than that, I don't know.

More samples tomorrow, more opportunities to break ampoules. Yay?

[Edited]
Nine new ampoules. Two stayed intact all the way. The optimist will say that 2/9 is infinitely greater than zero; the pessimist will say that 2/9 is still crap as an average. Hm.

[Edited again]
Five more ampoules. All successfully sealed - woot! Now let's see if this ability is permanent or some fleeting thing.