On 04/06/13 00:51, Dave Liquorice wrote:
On Mon, 03 Jun 2013 22:55:35 +0100, RustyHinge wrote:

I doubt very much that the draught excluder strip is phosphor bronze,
which is a bearing material.

Also known as "Atomic Strip" still available and the ads say it's
pure copper. However the old stuff that I have (somewhere) is very
springy, far more than copper from a bit of tube or hot water
cylinder. I guess it might be cold rolled to harden it but wouldn't
that also make it brittle?

May be beryllium copper - the stuff Beatty uses for tellingbone wires.
Very springy and not distorted easily. (I use it for UHF/Microwave aerials)

Certainly the stuff I have, which is probably in the order of 50
years or more old hasn't tarnished like copper does in air. It's not
bright but it still has a bit of a shine not the matt dark brown that
copper goes in dry air. I'd say mine at least is a copper alloy of
some sort, Phosphor Bronze is what my Dad called it. Beryllium Copper
is also springy and hard but beryllium is toxic and I suspect more
expensive than tin...

Hum. Copper will alloy with a surprising number of metals to make a
range of 'bronzes': aluminium, nickel, zirconium, tin and beryllium are
the most common (I think...) but a little silver counterintuitively
hardens it to something like steel.

--
Rusty Hinge