Wheels on fire

That damned seat post is coming out! Caustic soda (Sodium Hydroxide) mixed in water, when it reacts with aluminium, produces hydrogen. Like this: 2Al(s) + 2NaOH(aq) + 6H2O → 2Na+(aq) + 2[Al(OH)4]- + 3H2(g)
Obviously this means absolutely nothing to me because I just cut and pasted it from the web. But it does catch fire if you put a match to it. And that's all you need to know if you like a bit of visual excitement.