The Natural Philosopher wrote:
Andy Dingley wrote:
On 17 Oct, 18:41, Bill wrote:

Towards the end of the 5 years the copper tubes started to fall off.
Inspection showed that the solder had changed to what looked like a
crystalline form - sort of like a really terrible dry joint, but much
more obvious.

Web search for "grey tin", and the story of how Napoleon was defeated
in Russia because his army's trousers fell down.

Hmm Wiki states that bismuth or antimony may be used instead of lead.
Bit they are ,are they not, aabout 1000 times deadlier than lead?

Maybe - I really don't know - but medicines such as Pepto-Bismol contain
bismuth subsalicylate. And bismuth-containing medicines were used by Dr
Barry J. Marshall and Dr J. Robin Warren in their work on Helicobacter
pylori.

And your self-same source says this of Bismuth:

Scientific literature concurs with the idea that bismuth and its
compounds are less toxic than lead or its other periodic table
neighbours (antimony, polonium)[22] and that it isn't bioaccumulative.
Its biological half-life for whole-body retention is 5 days but it can
remain in the kidney for years in patients treated with bismuth
compounds[23]. In the industry, it is considered as one of the least
toxic heavy metals.
http://en.wikipedia.org/wiki/Bismuth

--
Rod