[gumby]

Hey kids, if you plan to play with Pu, what the author fails to mention is that it is not only radioactive but actually poisonous (chemically) as well.

On the other hand, another little known fact is that you can weld it, which isn't true of all metals.

[vixen99]

Unthinking, I'd always gone for Ralph Nader's 'the most toxic substance known to mankind'. http://atomicinsights.com/how-deadly-plutonium/ tells a different story. Point being - 'During the Manhattan Project in 1944 and 1945, 26 men accidentally ingested plutonium in quantities that far exceeded what is now considered to be a lethal dose. Since there has been a consistent interest in the health effects of this brand new substance (first discovered by Glenn Seaborg’s team at the University of California in 1940), these men were closely tracked for medical studies. Forty Years Later As of 1987, more than four decades later, only four of the workers had died and only one death was caused by cancer. The expected number of deaths in a random sample of men the age of those in the group is 10. The expected number of deaths from cancer in a similar group is between two and three.'. On the other hand, better play safe!

[dboreham]

Not sure they "discovered". Strictly speaking the Berkeley team first isolated, or produced Pu. Its theoretical existence had been known for a while prior (which is why they were trying to produce it). I mean, it wasn't that they were walking around and picked up and chunk and wondered what they had discovered. The project was entirely for the purpose of producing something every Nuclear Physicist knew must exist. They succeeded in making a small piece, which nobody had done successfully before.

[anfractuosity]

That's interesting with respect to welding. I just assumed all metals could be welded, do you know the reason why some can't out of interest.

Also is plutonium welded for any application, out of curiosity?

[petee]

One reason certain metals can't be welded is how their crystalline structure is altered by the process, creating a weak or brittle weld/HAZ (heat affected zone: weaker metal surrounding the weld/filler metal altered by heat)

Some metals also have difficult or impossible cooling rates - welding stainless to carbon steel will make a weak weld that is almost guaranteed to crack while cooling because one metal cools and contracts much faster than the other.

The topic is fairly complex, but there is a good textbook/reference for welders put out by the Lincoln Arc Welding Foundation called "Metals and How To Weld Them" that goes deep on structure and metallurgy, in a readable way.

[reitanqild]

I just assumed all metals could be welded, do you know the reason why some can't out of interest.

Not a welder but spent some time in farming school and on farms:

IIRC Not even all steel can be welded (i.e. at least not in a practical way using standard tools.)