I'm not mad and I don't want a Darwin Award. There, that's set the
ground rules now to the question.

We have a Sodastream which is fantastic - provided we can get hold of
replacement CO2 cylinders we can have sparkling water in unlimited
quantities without the hassle of dragging heavy bottles of water home
from the shops and the associated waste packaging.
Sadly Sodastream as a company are a disaster to deal with. They seem
to feel that they can make most money by messing everyone around by
changing the system occassionaly and making the old cylinders
obsolete. Of course they claim they haven't made them obsolete it's
just that they are now hard to get hold of - and Sodastream are the
only supplier - oh, and they now have a new system which you can buy
for a mere £50 - and the only real difference is the cylinder fitting.

So, I'm exploring the possibility of either (a) finding someone who
can refill the cylinders with food grade CO2, or (b) getting hold of a
more universal CO2 cylinder and somehow coupling it to the existing
Sodastream mechanism. Does anyone have any ideas of where to try for
an unauthorised refill? I've already tried my local BOC agent who
doesn't have a suitable fitting for the cylinders so can't refill
them.

Alternatively, and much more uk.d-i-y, any thoughts on the
practicalities and dangers of a homemade system. I guess I can find a
way to couple a cylinder to the back of my existing machine but I've
no idea what pressure these cylinders are at and what pressure the
Sodastream relief valve operates at. For those who are not familiar
with the system the Sodastream is very simple and just allows gas to
flow into the water until the pressure opens a relief valve and it
"farts" indicating that the fizzy water is ready.

Any thoughts?
Calvin