There are 2 reasons why copper isn't used for a FV
1 Risk of poison is High , as copper can oxidise into highly poisonous compounds ( green or blue spots on the copper are copper sulphates, nasty out )
2. Too much copper is detrimental to yeast growth , usually a healthy amount is provided by having a bit of copper pipe in your mash tun or in your kettle as a hop strainer .
I think I'm quoting Palmer here but I can't remember .
It might be possible to build a fermenter out of copper and line it with high grade polythene, such as wine makers sometimes do , but where you'd get the stuff I don't know
On the dimensions of the SS conicals , I'll have to check the height again but I reckon without legs its about 750mm High , and the circumference is 111mm , but with the bits on the lid and clasps the effective diameter is likely 55 - 60 mils It should certainly fit in a fridge.
I'm still working on a caddy or legs for them though , that may add to width , but there are ways to ensure it don't .
