Thanks to everybody for the suggestion. I used Marley solvent cement (a remainder from a previous diy drainage job) and it has provided the best result (over a number of other supposedly fit-for-purpose superglues). Glue dries transparent, no mess, good mechanical strength good, fast and controllable setup with a more complicate situation than just fitting one PVC pipe into another.
This triggers a second question: the glue I used - bought in Autumn
2005 - has 04/2006 as its expiry date, with an explicit recommendation from the manufacturer not to use it beyond that date. Nevertheless, I used it in my experiment all the same because I was impatient to test it and see the result.
I would not generally risk an unsound result just to save a fraction of the approx. =A32 spent on the small-size tube more than two years ago. However, I am wondering whether in your experience this expiry date issue is driven more by market greed rather than by an acknowledge technical problem with chemical instability of the glue components that would make it no more effective after its expiry date.
We all know that in a number of cases (food, medicines, materials) product expiry dates are artificially shortened to boost sales. In this particular case I suspect that if the official shelf life is 12 months, the real one could be anything in the renge of 36 months, with decreasing performances over time. My supposedly 2.5 years old glue takes considerably more than 15 seconds to become rock solid and miniclamps are needed to support the hardening process, but apart from this it delivers the expected result.
I'm just curious to see whether this empirical observation is shared by other people or I've just been simply lucky this time.
Best,
W.