Aluminum foil (2021)

I wasn't expecting to see Dernocua at the top of HN today with 53 comments. You can download Dernocua as a whole from http://canonical.org/~kragen/dernocua/ if you're interested.

I'm happy to answer any questions. (Well, almost any.)

>...and conductive, rivaling copper.

That isn't true for either thermal or electrical conductivity. So I don't know what is meant here.

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.

> 50¢/m² is 50¢/kWp in a solar concentrator, or 0.05¢/Wp, which is noticeably cheaper than photovoltaic cells, currently around 18¢/Wp, 360 times more expensive.

A photovoltaic cell is a solar panel, and a piece of aluminium does nothing, am I missing something here?

This was on S01E01 of How It's Made. Probably one of the best segments in the shows history.

At my previous job we made >1m wide 8um thick copper foil by electroplating it onto a giant titanium drum from blue copper sulfate solution. It was quite impressive.

>Alternatively, though, it might be possible to stiffen the foil by making the equivalent of corrugated cardboard out of it, maybe using aqueous boric acid (US$1.70/kg according to Potential local sources and prices of refractory materials) or borax as the glue. The surface tension of water is ample to hold aluminum foil in place until the water dries.

Hello Amazon? Billion dollar idea here. This needs more attention. You could have fully recyclable aluminum boxes instead of cardboard. Imagine your box supply chain literally being a circle.

Photographers and cinematographers are like: ohhh let me sit you down and tell you all about my love of blackwrap.

Aluminium foil is amazing stuff. Aluminium foil adhesive tape, in particular, is incredibly useful.

Being a multi-domain kind of geek the random tapes section of my tool drawers also contains mylar tape and fashion tape (or "tit tape" as a friend calls it) but the aluminium foil tape has proved to have many useful applications.

It's non-toxic and food safe, and yet a significant number of people on the internet still act like it's poison that will give you Alzheimer's. I wonder how many of those people touch their lips to the lid of an aluminum beverage can. Or how they might bake a lasagna at home.

I just skimmed and read parts but I really enjoyed reading this. It's like my own handwritten notes which are just stray thoughts about a subject. Maybe I should publish more of those and I love the idea of just musing about a single thing, like Aluminum Foil (though it's very interesting stuff).

>Robert Lang recommends laminating tissue paper on one or both sides of kitchen aluminum foil to make “tissue foil”, which for years he considered the ideal origami material.

The sculptor Kim Beaton likes to champion foil as a "metal clay" for sculpting. Keep it full of air pockets and it's easy to shape. You can use hot glue to put parts together, and then cover it in other clays for fine details and coloring. She does quick demos for tour groups at Weta Workshop in New Zealand.

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.

Um, what? I'd like to see a sketch of this 100,000 part compiler very much. I have no idea what he/she is talking about here, in the slightest. But I am intrigued!

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.

Worth noting that aluminum is the most abundant metal of the Moon’s highland geography, thus excellent for bootstrapping beyond Earth.

Aluminum is honestly a miracle material that has no business being as inexpensive as it is (of course, this is only since the invention of the Hall–Héroult process, before which aluminum was one of the most expensive metals known despite making up ~8% of the crust).

Amazing. This reads like someone left Hunter S. Thompson alone with a roll of Reynolds Wrap.

Im interested in using honeycomb aluminum panels for some projects but curious why its so freaking expensive?

There's even a song about it:

https://youtube.com/watch?v=urglg3WimHA

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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.