On Sun, 22 Jun 2008 13:11:06 +0100, MM wrote:

I don't need it to boil. Just to get hot.

You may not need or even want it to boil but if you have a decent
collector how are you going to stop it on bright day?

So this must exclude plastic (i.e. non-metal) as a material, yes?

Depends a cold water storage tank is for that, cold water. I'm sure there
will be plastic tanks out there that can cope with 100C without trouble
but I doubt you'll find them ina DIY shed or builders merchant.

--
Cheers
Dave.