
The Lightest Metal Ever (2015) [video] - lisper
http://www.boeing.com/features/2015/10/innovation-lightest-metal-10-15.page
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GordonS
I thought this was familiar, and a search revealed it was posted here twice
back in 2011... so, not exactly new.

[http://insights.dice.com/2011/12/13/ultralight-metallic-
micr...](http://insights.dice.com/2011/12/13/ultralight-metallic-
microlattice/)

[http://newatlas.com/ultralight-micro-lattice-
material/20537/](http://newatlas.com/ultralight-micro-lattice-material/20537/)

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ljf
Even this article is a year old (2015) but yes this has been around for a
while.

Interesting none the less.

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staticfloat
Does it bother anyone else that the audio is so highly edited? They're
literally stitching together sentences that she did not say. I'm used to
videos cutting phrases together, but they're cutting individual words together
in a way I've never see^B^B^B heard before.

~~~
maxerickson
You probably just don't notice when it is done in stuff with higher production
values.

To me the most likely explanation is that they wanted a certain (short) run
time and she only did 1 take.

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imagist
So my response is _don 't do that_.

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glibgil
Don't do one take? Uh, if I was her I wouldn't do more than one take. I might
not do the shoot at all. I wouldn't get paid more by doing a promotional video
shoot. Why would I care? Why would she?

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avmich
Presenting your ideas is an important part of most, if not all, high
complexity works. If you're an engineer - present your ideas and results, so
you can get better feedback, if not more appreciation. If you're a product
person, explain the results to practically anybody - improves conversations
which lead to better mutual understanding. For executives it's even more
straightforward - remember how many hours Steve Jobs spent preparing demoing
first iPhones?

~~~
glibgil
What you describe is the type of stuff that is largely unimportant. This is
not a commercial for a retail product, it is for an unapplied manufacturing
technique. It doesn't mater who you wow with this stuff. It has an application
or it doesn't. In fact, for all the good this video does, they should have
just wrapped an egg it the stuff and dropped in from a building. 15 seconds of
potentially viral video would have done a better job than this video. The
video is fine for telling an engineering story, however. She and the hack
videographer did a fine job for a low-stakes presentation. It's fine, really

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imaginenore
The title should say "lightest metal structure".

Lithium is the lightest metal. (Though technically Li-6 isotope is even
lighter)

[http://scitation.aip.org/content/aip/journal/jcp/27/5/10.106...](http://scitation.aip.org/content/aip/journal/jcp/27/5/10.1063/1.1743927)

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Kenji
When someone talks about 'light' metal, I assume they incorrectly refer to the
weight of a solid cube (cm^3) of the metal, that is, the density. A wireframe,
to me, is not a metal. It consists of metal but its structure, including air,
is not a metal. I don't say my cupboard is made out of the lightest wood in
existence because if I divide its volume (including the air inside!) by its
weight, it's lighter than any cube of wood.

~~~
VLM
Ironically, balsa wood, pine, and oak are all just boring same ole cellulose
and lignin composite surrounded by varying amounts of nothing. Used to be
surrounded by water when the tree was alive.

Yes yes there are trivial details in that pine is 1% pine tar and oak has 1%
whatever dyes and stuff to make it darker color, but to one sig fig or to 10%
accuracy, its all the same.

~~~
harperlee
You make a very good point, but we can amend
([http://paulgraham.com/disagree.html](http://paulgraham.com/disagree.html))
the GP's argument to say that such macroscopic holes are not very impressive.
Now if they were as small as those in balsa, and invisible to the eye... then
on a macroscopic level it would appear to be superlight metal. It could also
help that the holes are sufficiently small as to not percolate
([https://en.wikipedia.org/wiki/Percolation_theory](https://en.wikipedia.org/wiki/Percolation_theory)).

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grondilu
Question: will it ever be possible to wrap a thin impermeable film around a
structure like that, suck out the air inside and end up with a lighter-than-
air solid in order to build vacuum airships?

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sandworm101
Theoretically yes, practically no. But why bother? Supporting the walls by
filling the space with a gas lighter than air would be more efficient.

~~~
knodi123
Theoretically, no, not this particular substance.

But anyway, the reason people are fascinated with the idea is that vacuum is a
renewable and abundant resource. Heck, space is almost completely full of it.

All of the lighter-than-air gases I'm aware of have downsides, like hydrogen's
permeability and flammability, or helium's rarity and price.

~~~
VLM
Hot air is lighter than air, and aerogel like low density materials have some
weird property where the thermal conductance is lower than bare gas when the
mean free path in the aerogel is shorter than the mean free path in bulk gas.
In other words they're better hot air balloons than actual hot air balloons.

Something interesting to think about is if they don't leak heat energy very
well, and the exterior is something heat proof (steel foil?) you can heat up
the air inside to arbitrary temps until radiative glow exceeds the other
thermal losses. So if you think nylon hot air balloons are high performance,
imagine balloons with much higher lift per volume. A liter of air weighs about
a gram so its always going to take a large piece of aerogel to lift me (I
weigh quite a few grams) but ...

A hot air balloon sized piece of aerogel is not economically viable right now,
even for the military... or is it?

~~~
knodi123
Low-density materials surrounded by a thin shell are still going to weight a
lot more than air surrounded by a thin shell. Also, you have to look into how
this is going to be heated. For a hot air balloon to work, all the air inside
has to be hot. If your balloon is filled with an amazingly efficient
insulator....

Also, the reason airships use lighter-than-air gas is because then they don't
have to carry lots of heavy fuel for heating air. Things like fuel, and pipes
to carry heat throughout your aerogel, will rapidly eat up any efficiencies
you gained.

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ythl
Basically cardboard made out of metal?

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davesque
I feel like the video was a bit sales-oriented. Is it just me?

~~~
zerohm
Yeah, call when you have a really cool application / problem solved. Also the
Astrodome is probably 99% air.

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Graphon1
tough crowd! no love for basic R&D.

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davesque
I'm not saying I don't like basic R&D. Quite the opposite actually.

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terrage
21st Century Chainmail! Our forefathers would be proud.

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markwaldron
Does the lack of centering with the play button bother anyone else?

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sandworm101
That, and the constant background hiss in the audio. I get that they are going
for a windy/airy feel, but it comes off as a poor recording.

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nightcracker
It's... 3D chicken wire? Not terribly impressed. From the video it shows that
it's also super weak. You won't be building airplanes with this stuff.

This obsession with super light materials that "are strong for their weight"
seems a bit useless to me. It never seems to scales to something that weighs a
medium amount while maintaining its strength to form something actually
useful. Supposedly, spider silk is incredibly strong. But if you can't scale
that strength there is no point to it.

At least aerogel has purposes for extreme insulation, but as this is made out
of metal I don't see use there either.

Nevertheless, I applaud progress.

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baldfat
If the exterior is rigid and the inside is filled with this material it could
be strong enough for many structural projects. As was shown in the video our
bones are created in the same way. I think the issue will be cost.

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13of40
Yeah, when I read about this before, I think they were making it with a 3D
laser sintering technique, which comes with some baggage. Mainly it's slow and
with current technology I don't know if you'd be able to print a continuous
sheet of it versus the cubes they showed in the video.

