So this won't get lost in a silly thread, I thought it might be useful
to others
to have real data on "Skin Effect" for RF.
http://www.microwaves101.com/encyclopedia/skindepth.cfm
http://www.rfcafe.com/references/electrical/skin_depth.htm
http://www.rfcafe.com/references/electrical/cond_high_freq.htm

The first link has a very nice graph that shows how rapidly skin
depth
decreases with frequency.

The lab I worked at had walls of 1/8" copper mesh that looked to be
about 22AWG. I thought of measuring it, but decided I didn't want to
risk damaging it. I sure couldn't afford to replace a section!

1/4" rat wire will work up to at least 150MHz.

And any openings in the walls must be less then 1/10 the highest
frequencies wavelength for protection against very high RF fields,
such as EMP, NEMP, HEMP etc.

If anyone is bored enough we have a very nice flame war going on
in alt.survival. Given that we are arguing over science and unknowns,
I feel somewhat like a theologian arguing about "how many angels can
dance on the head of a needle."

Terry