[DavidPeiffer]

For just that weight of metal...not too expensive. To get it formed into that shape, potentially very expensive.

It looks like aluminum. Someone posted 23.5" x 23.5" x ~144" as the dimensions. This comes out to be 46 cubic feet, and would weigh about 7,700 lbs. A floor of the price would be ~40 cents/lb scrap price, or ~$3,100. Ballpark 80-120 cents/lb might be a more realistic price if it were straightforward to manufacture like that (which it's certainly not).

As an industrial engineer and former employee of one of the largest aluminum plants in the world, I can safely say I doubt it is solid rolled aluminum, and bet it would be way bigger of an extrusion that is possible. And logistically, it would be far easier to transport to a remote location via helicopter if it wasn't solid. Any machining, metal forming, etc. would require specialized large equipment, and would quickly drive the cost up, potentially an order of magnitude higher than material costs.

[saalweachter]

Which is all wrong.

The monolith in 2001 had dimensions in ratios of 1:4:9 [and continuing into other dimensions...].

Why the heck would you go to all the work of putting a monolith of the wrong shape out there?

[rbanffy]

1:4:9 is too 2000's. 1:9:49 is what you want these days.

[chordalkeyboard]

Can you please explain the significance?

[shemnon42]

television ratios joke. 4:3 became 16:9 for widescreen. Further from square and closer to the "golden ratio", so make something closer with different prime squares.

1:22:33 becomes 1:33:77

[rbanffy]

In reality I was joking about fashion. The new trend in monoliths is a metallic finish and slender proportions, skipping one prime square - The original is 1²:2²:3² and the new one is 1²:3²:7² (skips primes 2 and 5). The dimensions continue, of course. In Clarke's 2010 it's kind of assumed it'd mean it'd be integers, but the new one fits better with primes.

[slightwinder]

Nobody prooved it has any relation to 2001. It's not even black, why do people even assume it must have some connection with that story?

[Zenbit_UX]

Because of the hilarious implication that the installer believe intelligent life had not yet been seeded in the Utah area.

[Youden]

> Any machining, metal forming, etc. would require specialized large equipmen, and would quickly drive the cost up, potentially an order of magnitude higher than material costs.

It seems unlikely that there are serious tolerances to be kept here, couldn't this just be cast messily using a sand/clay mould and then cleaned up with portable power tools?

That way you don't need any special equipment and you can use whatever Aluminium you can get your hands on. Hell, you can even recycle Aluminium cans.

[DavidPeiffer]

Large scale castings are also tricky. You can't cast a rectangular prism and get good results. As the metal freezes (solidifies), it shrinks. You'd end up with a very poor surface finish at best, and chunks missing at worst. The shrinkage needs to be made up for with some additional molten metal.

The fix is pretty simple though. You need directional solidification, meaning the freezing starts on one end and moved towards the other. If you apply a draft angle of 1 degree or so to the parallel faces, you will have enough difference in dimensions to get directional solidification working fine.

>That way you don't need any special equipment and you can use whatever Aluminium you can get your hands on. Hell, you can even recycle Aluminium cans.

I'd advise against mixing alloys, but you may still be alright to get something, but it will be worthless if you try to recycle it again. Mixed scrap fetches far less than sorted scrap when you try to sell it. E.g. Some alloys might allow 1-2% copper, while others require <0.01% copper. Each pound of type 1 mixed with type 2 requires lots of pig (pure aluminum, no alloying elements) to be added to get the proportions back to something you can legally call whatever alloy you're targeting.

Aluminum cans aren't a wonderful source for things like this because they contain a thin plastic film on the inside to prevent the liquid contained from having its flavor tainted. Normal recycling processes handle this fine, but cannot handle the plastic labels added on many small brewery cans. Those should be cut off prior to recycling.

------

Side note - It is incredibly energy intensive to mine bauxite, refine it through an electrolysis process into alumina, and finally alloying it into your preferred type of aluminum. It recycles incredibly well though. Recycling 1 ton of aluminum saves about 95% of the energy compared to new aluminum. This 95% savings is about 14,000 kWh. The energy intensity is part of why Iceland houses 4 smelters. With nearly 100% of electricity production coming from hydroelectric, they have incredibly cheap electricity, and it's economically viable for the likes of Alcoa, Rio Tinto, and Century Aluminum to haul bauxite ore from around the world to a tiny country with almost no manufacturing base, process it, then haul it around the world to its final destination.

[caf]

Iceland's electricity production mix seems to be typically about 70% Hydro and 30% Geothermal (which does not change the overall point - just interesting).

[DavidPeiffer]

Ah, good catch! I was rusty on my numbers from a year and a half ago when I wrote a paper on this for school. Back in the 80's they were nearly 100% hydro.

https://en.m.wikipedia.org/wiki/Electricity_sector_in_Icelan...

When I visited in 2018, we came across a 5 kW turbine installed in 1927 near a famous waterfall. It's no longer online, but was neat to see.

https://maps.app.goo.gl/pLuSyKnStd4smgCCA

[geggam]

Just a note about aluminum recycling. Humans tend to trash things instead of recycling. Out here in the desert where people dump things I have noticed old steel cans rusted to nothing mixed with aluminum cans which seem to not degrade over time.

Arguably if you are worried about the environment and account for human laziness steel cans are better for the environment IMO

[DavidPeiffer]

I've read around 75% of the aluminum ever produced is still in use today. If you machine a new surface on aluminum, it will form an aluminum oxide layer in a matter of hours. I believe (but am not certain) this effectively prevents it from degrading the way steel does over time.

Aluminum can recycling rates tend to be higher in states that offer deposit programs. Back when they were getting introduced in the 80's, $0.05/container had a lot more buying power than it does today. It's enough of an annoyance now, they'd be best off eliminating it or increasing it to ~$0.15 or so. Or since this is HackerNews, maybe we could use block chain technology to verify each can is properly recycled and reimburse with bitcoin.

[itronitron]

A classmate of mine in college made all of his sculptures out of plywood and Bondo, reasoning that they were likely to last much longer than anything made out of metal due to having no scrap value.

[rtkwe]

It would be hard to maintain a flat surface that large manually, doable but tough.

[usefulcat]

> And logistically, it would be far easier to transport to a remote location via helicopter if it wasn't solid.

Cue reddit researchers combing through old helicopter flight plans/paths from the relevant time frame? Though I would have thought an off road vehicle might be more likely; looks like it's only about 2-3 miles from the nearest road.

Edit: actually there appears to be a dirt road ~1k feet or less away

[chrissnell]

The road is Lockhart Basin Road, well-known among Utah off-roaders. I've been there, and also camped on one of the fingers of Hatch Point, directly above the monolith.

I took this one on the point overlooking the monolith: https://www.instagram.com/p/BUFR5GZF2fX/?igshid=11nr2ljs2dh6...

I took this photo not too far from the monolith:

https://flic.kr/p/8MWSQp

[DavidPeiffer]

I didn't realize it was so close to a road. I'd really like to think it came in via helicopter though, because it's a more cool and clandestine story.

[tristanb]

Sand cast and polished...

[DavidPeiffer]

As I noted in another response, you can't cast a rectangular prism and expect a good result. You'd need to add some angle to the edges to ensure it solidifies correctly, but doing so takes away from the monolith feel.

That's also a lot of polishing for the finish you would get from sand casting.

[nullc]

There is a video of it, it has a triangular cross section.

There appear to be screw holes (or rivets), so I'm going to guess that it's three aluminium sheets screwed onto an interior scaffold.

https://www.instagram.com/p/CH_iU8JgeIr/