This made me wonder about a 3D printer alternative that builds things by folding a thin sheet of metal into arbitrary shapes instead of extruding filament.
I appreciated the paean to aluminum foil in Project Hail Mary where (spoilers) the hero uses it as bowling pins and to reproduce astrophage to eventually save two worlds. It's right up there in the pantheon of useful things with duct tape.
I was enjoying the ADHD hyper focus writing, kind of following along, then:
> If we figure that the foil can meaningfully change direction every 20 μm, then we might think of an aluminum-foil machine as being made of “moving parts” on the order of 1000 μm² (50 μm × 20 μm), 1000 “parts” per square millimeter of foil; a roll of kitchen aluminum foil is enough to fabricate some 4 billion “parts”. A bootstrapping compiler might require 100 000 parts and thus a square centimeter of aluminum foil, cut and folded around into a shape a couple of millimeters in diameter. If it were doing only one thing at a time, and needed 10 seconds to construct/assemble each moving part, it would take about 12 days to recompile itself. This is probably adequately fast, barely, but probably not adequately robust against errors. It would probably be better to design it to have more parts and do many things at once, enabling it to be faster and correct errors.
I've read a lot of his other writings so that context might be informing my reading here but it sounds like he's pretty straightforwardly discussing the potential of aluminum foil as a uniform-feedstock-slash-construction-material for a hypothetical self-reproducing microfabricator.
Another thing not mentioned on there about aluminium foil is how clean it is. We work with a laminar flow hood and pull a fresh layer of foil anytime we are working to create a clean base to work on. I can guarantee you that if you run a swab over a fresh sheet of foil and smear it onto sterile nutrient agar that it won't grow anything - that said, we use costco foil which is thicker gauge and not the budget thinner stuff which is definitely inferior.
This was on S01E01 of How It's Made. Probably one of the best segments in the shows history.
Im interested in using honeycomb aluminum panels for some projects but curious why its so freaking expensive?
This is pretty much just rambling about how amazing aluminium foil is because it's so thin and that might enable all sorts of wonderful imaginary applications. Very HN. It's aluminium foil.
[delayed]
That's the neat part though, isn't it? It's a product that's so good that there's no everyday alternatives to it. I was researching cat litter options recently and cat owners do a lot of thinking and talking about litter, because there's a variety of different materials, none of which are solidly better than all others in all situations. But aluminium foil is so good that we don't even think about it, because it's by far the best product for every application that we use it for.
You sound like someone who hasn't explored the upper limits of what aluminum foil can solve!
Has a kid, my mom used to pack my lunch in aluminium foil and everyday was a challenge of trying to make the perfect aluminium ball and throw it in the trashcan[1] on the first try!
1. Recycling was a vague concept in the 80s & 90s