Im interested in using honeycomb aluminum panels for some projects but curious why its so freaking expensive?
IshKebab•Jul 6, 2026
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.
post-it•Jul 6, 2026
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.
Forgeties79•Jul 6, 2026
You sound like someone who hasn't explored the upper limits of what aluminum foil can solve!
whynotmaybe•Jul 6, 2026
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
bluGill•Jul 6, 2026
Your local recycler probably doesn't want al foil even today when recycling is a big thing.
IshKebab•Jul 6, 2026
Read this guy's ramblings and give me one cool application that he has found. Lots of "maybe it could do this!" and "it can do <completely useless thing>!"
Forgeties79•Jul 6, 2026
Aluminum foil makes a great, cheap light bounce for photography on the fly. Your photos will instantly look better either reflecting to the back of their head 180 from shot, or as a fill for their face.
roughly•Jul 6, 2026
The trick to being a good hacker is acquiring a sufficient supply of useless information, such that when that information is suddenly not useless, you have it at hand.
Which is to say, it's your job to figure out what the cool applications are.
nyeah•Jul 6, 2026
What's really thin is the oxide layer on the surface
When exposed to air at room temperature, or any other gas containing oxygen, pure aluminium self-passivates by forming a surface layer of amorphous aluminium oxide 2 to 3 nm thick,[4] which provides very effective protection against corrosion. Aluminium alloys typically form a thicker oxide layer, 5–15 nm thick, but tend to be more susceptible to corrosion.
wolfi1•Jul 6, 2026
it usually is not only aluminium oxide but a mixture of aluminium oxide and aluminium hydroxide if it is normal (read: moist) air
t1234s•Jul 6, 2026
This was on S01E01 of How It's Made. Probably one of the best segments in the shows history.
vessenes•Jul 6, 2026
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!
wgd•Jul 6, 2026
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.
delichon•Jul 6, 2026
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.
0-_-0•Jul 6, 2026
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.
whilenot-dev•Jul 6, 2026
I made an artwork in 2013-ish, where I attached an aluminum foil to a good DC motor. I mounted it from the ceiling with 2 stepper motors to control height and one orthogonal axis. The motor would unwind the foil by accelerating quickly in either direction (CW/CCW). By changing directions it would also create folds and stabilize the emerging shape: https://imgur.com/a/gaRKGtQ
I always imagined an additional stepper motor to cover an area like a delta 3D printer and liked to think about the difficulty in creating the 3D software, and the need to find a solution to simulate the unwinding-into-shape through some physical model.
This is optionally followed by a pressurized furnace for sintering.
toast0•Jul 6, 2026
My college had a 'rapid prototyping' machine circa 2000 that worked in paper. Roll out a layer of paper, cut through the top layer, something something glue, roll out the next layer, etc. No reason that couldn't work with aluminum foil.
secretslol•Jul 6, 2026
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.
MezzoDelCammin•Jul 6, 2026
any tips on how to reliably get that "thicker gauge" one? I've been craving it since maybe 20y ago when I got a roll from my old stint in a restaurant. I've tried buying some rolls by "heavy duty" labels and these days it's just as likely to be one of those thin "look at it funny and it tears".
dofm•Jul 6, 2026
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.
1970-01-01•Jul 6, 2026
>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.
That would be hell on everybody's box-cutters (and fingers). I already cut myself too often on shipping boxes.
bluGill•Jul 6, 2026
aluminum foil is generally not something you can recycle. Not that it can't be recyled, but the oxide to pure aluminum ratio is high and so you don't gain much since you need all the energy of refining in the first place to get back to something usable.
Amazon needs stronger boxes than foil anyway. Cardboard is likely best for them.
cperciva•Jul 6, 2026
the oxide to pure aluminum ratio is high
For some definition of high? Standard foil is around 20 um thick while the oxide layer only goes about 10 nm deep.
codazoda•Jul 6, 2026
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).
unchocked•Jul 6, 2026
Worth noting that aluminum is the most abundant metal of the Moon’s highland geography, thus excellent for bootstrapping beyond Earth.
0xWTF•Jul 6, 2026
Amazing. This reads like someone left Hunter S. Thompson alone with a roll of Reynolds Wrap.
jstanley•Jul 6, 2026
> 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?
cdu1•Jul 6, 2026
I think the implication is you can use it to reflect additional light onto your photocell, improving the power output for a smaller cost than purchasing an additional cell.
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).
ceejayoz•Jul 6, 2026
Yup. The very tip of the Washington Monument was made of aluminium, which made it faaaaaancy. Two years later, not so much.
badc0ffee•Jul 6, 2026
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.
jagged-chisel•Jul 6, 2026
1) all of them
2) glass dish
badc0ffee•Jul 6, 2026
I use a glass/Pyrex dish, but put foil on top. I guess you could use a fitted glass lid instead, depending on the container.
ceejayoz•Jul 6, 2026
I've only seen people concerned with it in antiperspirants, where it's a salt. (And to be clear, I think it's BS.)
As with NaCl, it's at least possible that the salt and the pure-ish variant aren't quite the same thing.
br0ceph•Jul 6, 2026
i heard aluminum food containers are often coated with toxic liners, like plastics, bpa, and pfas.
If Alzheimers isnt a risk with pure aluminum metal, id say those liners are a huge risk.
Are kitchen foils coated? Im pretty sure cans are most of the time.
badc0ffee•Jul 6, 2026
"Plastic" in general isn't toxic as a liner. It's used in plumbing, and in zillions of containers for potable water and foods. When you get food from even a nice restaurant, they probably marinate meat in a plastic container, and squeeze fruit juice into a plastic container.
I've also never heard of a plastic/Alzheimer's connection, only one claimed with aluminum.
goda90•Jul 6, 2026
>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.
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.
18 Comments
1. Recycling was a vague concept in the 80s & 90s
Which is to say, it's your job to figure out what the cool applications are.
https://en.wikipedia.org/wiki/Anodizing
When exposed to air at room temperature, or any other gas containing oxygen, pure aluminium self-passivates by forming a surface layer of amorphous aluminium oxide 2 to 3 nm thick,[4] which provides very effective protection against corrosion. Aluminium alloys typically form a thicker oxide layer, 5–15 nm thick, but tend to be more susceptible to corrosion.
I always imagined an additional stepper motor to cover an area like a delta 3D printer and liked to think about the difficulty in creating the 3D software, and the need to find a solution to simulate the unwinding-into-shape through some physical model.
EDIT: unwinding GIF here: https://imgur.com/a/VP3gEiv
https://postimg.cc/Q9vjhdrk
https://postimg.cc/9D1Vzphj
https://mantle3d.com/
https://mantle3d.com/how-it-works/
This is optionally followed by a pressurized furnace for sintering.
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.
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.
Amazon needs stronger boxes than foil anyway. Cardboard is likely best for them.
For some definition of high? Standard foil is around 20 um thick while the oxide layer only goes about 10 nm deep.
A photovoltaic cell is a solar panel, and a piece of aluminium does nothing, am I missing something here?
2) glass dish
As with NaCl, it's at least possible that the salt and the pure-ish variant aren't quite the same thing.
I've also never heard of a plastic/Alzheimer's connection, only one claimed with aluminum.
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.
https://youtube.com/watch?v=urglg3WimHA