Help on big caps / sources please

Got tired of the yahoo ads, so am asking for help
1. Source of 20,000 uF / 80 or 100 vdc caps?
nothing around vancouver, new or surplus.

2. Have some rated 50v, can I safely series these
and expect them to be exposed to only about 1/2 the
total voltage each, without need for the Lexan
housing? (since these are surplus, I did my
30v trials with the power supply outside, and me
behind the metal garage door < grin >)

Thanks / mark