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xkcd #2929: Good and Bad Ideas
(imgs.xkcd.com)
Alt text:
While it seemed like a fun prank at the time, I realize my prank fire extinguishers full of leaded gasoline were a mistake.
Well, I just said carbon fiber, but to be more exact it is forged carbon SMC, so yeah, careful engineering involved. Same stuff Lamborghini is using for some structural components, so probably fairly fit to purpose.
https://en.m.wikipedia.org/wiki/Forged_composite