On 19/11/2019 21:51, Dave Liquorice wrote:
On Tue, 19 Nov 2019 17:57:47 +0000, Andy Burns wrote:

Calor say 95 kg full for their 47 kg cylinders. Mind you they have
quite a spread for tare weight 29.5 to 57.7 kg.

Yes, just noticed that, have they switched from steel to aluminium?
I wouldn't have thought so ...

Niether would I ali isn't that strong. Look at how much ali there is
in an alloy wheel compared to a steel one. Ali might have a lower
density but you need more of it to get the strength of steel, so the
weight ends up about the same.

Perhaps older cylinders were over engineered?

Calor did use aluminium for smaller (6 or 7kg ?) cylinders in the late
'70s or '80s. They were lighter and I think that they actually held more
gas than the steel equivalents.

SteveW