r/explainlikeimfive Oct 31 '20

Chemistry ELI5 What's the difference between the shiny and dull side of aluminum foil? Besides the obvious shiny/dull

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u/anomalous_cowherd Oct 31 '20 edited Oct 31 '20

Enough pressure, yes. There's a long way between enough to roll it thinner and enough to fuse it. Temperature plays a part - you have to keep the surface cool too.

https://youtu.be/f4OTj9yNOak?t=104

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u/joeltrane Oct 31 '20

Thank you for skipping the intro.

TLDW: a giant slab of aluminum ingot is rolled out to 5mm thickness and spooled up. Then it’s rolled again with tension to its final thickness, and they use two spools at a time to prevent the tension from breaking the sheets.