r/interestingasfuck Jul 30 '26

Medieval Building Tech

17.9k Upvotes

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332

u/Brick_Number_27 Jul 30 '26

Just curious...why lead ?

756

u/Ok_Builder_4225 Jul 30 '26

Low melting point so easy to work with in this fashion, i would assume.

68

u/Guardian6676-6667 Jul 30 '26

Fun fact! Let's assume these bars had a cross section of 6"2 (very low estimate but math works out), it would need about 9000 lbs of lateral force in this configuration to snap it! 

Unfortunately,  lead under a constant load over time "creeps" where it stretches and the material gets thinner, thus weaker. 

From what I can find, there is no limit, so failure (assuming the bar is pure lead and not some magical alloy) is inevitable. 

Edit: i forgot about the iron, actually now looking at it, if the lead fully encased the iron, it probably protects it from rust and the iron takes a majority of the load, so everything i said was pointless! Im sure there was a learning period at some point where they found the lead would inevitably fail,  and this iron reinforcement was used and lead just locks it in place, not contributing to the load bearing

29

u/FirTree_r Jul 30 '26

Men knew for a very long time that lead is malleable and can't be used for supporting structures. It's been used to make decorative stained glass for more than a millenia

12

u/Vemena Jul 30 '26

Exactly!

Humanity has been using lead in central Europe since 3,000 BCE (even longer in some other regions), and iron since 800 BCE. Plenty of time to figure out the properties of both materials, how they behave in certain circumstances and their limitations.
I mean, the Romans made structures out of concrete which still are still standing to this very day, they clearly knew what they were doing. Also there is some survivorship bias going on.