Well, between scrounging expert Bill, and a local guy, I've recently gotten my hands on several hundred pounds of sheet lead. I paid the local guy 50% over what the scrap yard would give him, which is less than half what it's worth, still, so all are happy here. But it looked like it'd been in a car crash, dropped from a plane, and then had a bulldozer driven over it a few times for good measure - folded up and interlocked out the wazoo. This is well past what you can just pound out with a hammer - you have to pull and pry apart those pinched pieces first. I'm partway through the process now, so you can even tell this is sheet lead(!). The stuff that's only 1/16 inch thick is easy, but the 1/4" stuff is...not so much. Big prybars and sweat, then hammer.
The need for this and the cerro-safe mentioned under materials became obvious when in a few seconds, the fusor gave me a dose worth a year of professional rad work the other day - to say the least, we think we have a major breakthrough on our hands, but it's one I want to live to tune up even better, so...here we go with the shielding. Sadly, I actually got (estimated) about 5 years worth in about a minute - there was so much it shut down all my data aq gear as well, frying some of it, so that's a guess, but it was about a month ago, and I live on so far. But Not Good. I'm not yet ready to give up the use of my senses to learn things and use cameras in a cave and so on - yet. This is major work out in the sun. But most of this I don't want to cut up till I have a plan for its exact placement (it's a pain to have to solder it back), so I'm doing it where the guy dumped it out.