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Folding Paper with a Hydraulic Press (medium.com)
144 points by SapphireSun on May 18, 2016 | hide | past | favorite | 31 comments

> Paper is made by bleaching wood pulp to remove everything but the cellulose, then pressing and drying it into sheets.

Nitpicking: my book on paper-making talks about fiber, "filler" and "glue" as the main components in any paper or cardboard sheet.

The type of fiber results in different qualities based on source material (types of wood, cotton, etc) and fibre length - every time paper is recycled the fibers get shorter, and less "fluffy". This is why toilet paper from recycled paper is coarser; it's also why toilet paper inherently wastes good fibers: the good stuff is made from fresh fibers. On the other end we have stuff like the paper used in newspapers. Eventually, the fibers get so short they can only be used for the type of brittle cardboard pulp you see in egg carton.

Combined with fiber length, filler materials determine characteristics like how porous paper is, or how stiff. Glue.. well, should be obvious what that does, and how different types and quantities affect paper.

None of this matters for Gallivan’s Theorem, other than perhaps the variation in compressibility that different paper types have. It might have an influence on the whole fusing-into-a-slab thing though.

This seems like an excellent context to provide a link to that book.

The Complete Book of Papermaking by Josep Asuncion[0]. It lives up to its name, and includes many of the paper/cardboard types it discusses.

[0] http://www.goodreads.com/book/show/2665596-the-complete-book...

No glue according to this source: http://www.paperonweb.com/A1010.htm

> Main ingredient of all paper is plant material. Loading or filling material such as clay, CaCO3, Talc, TiO2 etc. are used for higher brightness and better printability. Rosin, alum or combination of other chemicals is used to make paper water resistant.

I guess the book I mentioned just categorised things differently - I think the "glue" bit was mainly about water resistance and general durability. Then again, it's been years since I've read the book (and I don't have it with me to check it right now), so I might be misremembering it.

Either way, I admit that "chemical additives" would make more sense as a general label! I mean, adding a chemical to make paper fire resistance can't be called filler or glue.

Same "explosion" happens when he crushes a book with the press. Wrecks a camera. "Mayhem" as he says: https://youtu.be/PmvKlnhMjUw?t=1m55s

See, that is a significant point in favor of the above.

I had figured that the most plausible explanation was that elastic energy was systematically getting stored in the folds, largely because the folds were at right angles to each other (hence each one is a "spine" which forces the sheet to "stretch" to accommodate it). A prediction of this hypothesis is that a book would not catastrophically fail until a much higher pressure, and that it might fail like other objects do, by eventually squirting outward like putty.

It's possible that a hybrid approach is needed: this failure seems like a release of stored energy; this explanation needs to account for the energy storage in the cellular matrix (probably not that complicated) and then we have a ready explanation of why there is a catastrophic failure whenever the hydrogen bonds themselves begin to rip (as all the stored energy is released at once).

I'm not convinced that the same thing is happening here. If you look at the aftermath, it seems that the press has curved a hole through the book. The "explosion" seems to be the aftershock of the press hitting the table with force after forcing itself through the book.

You see a lot of paper debris in the air that looks similar to the striated but crumbly paper in the OP video.

You make a good point and I think it's both things, actually. 1) The bonds in the paper fracture 2) The elastic energy in the press causes the cylinder to drive downward, splattering the malformed paper in all directions 3) Which makes room for the cylinder to make it most of the way through the book.

Video has an interesting ending https://www.youtube.com/watch?v=KuG_CeEZV6w

That whole channel is full of interesting things being flattened.

This guy is a darling of reddit, and routinely gets his stuff converted to a GIF and towards the top of /r/gifs.

The guy has pretty awesome sense of humor!

The clay animal crushings are especially hilarious, the million-subscribers video is 14 minutes of clay animals getting crushed.

These youtube canals (also Cody's Lab, Red Hot Nickel Ball, Thunderfoot's science stuff, etc) are how I think education and science could work in the future. People are willing to pay and watch ads to support such content, it's much more interactive than TV shows thanks to comments, and there's very small barrier to entry. It's exciting to see how these channels will develop.

There were even already real discoveries made thanks to youtube and patreon (for example http://www.nature.com/news/sodium-s-explosive-secrets-reveal... ).

Just looked up the channels you mentioned as well as the hydraulic press one from the article and they don't look like viable sources of education to me. The Hydraulic Press and Red Hot Nickel Ball channels are purely entertainment along the same lines of "Will It Blend?" The other two are more in depth, but are still low (Thunderfoot seems to be a feminism/politics/atheism channel?) in educational value. They might serve to get people interested in science, but they're unsuitable for learning.

Is this the same as video games getting children interested in programming? Is that how it works, or do kids turn to programming because they want to make video games? If the latter then there's not much value at all in these channels. No one learns computer science from watching Call of Duty videos.

I meant the science stuff, not the feminism/atheism/mythbusting rants.

Thunderfoot made some videos on youtube sponsored by patreon. He was experimenting with alkalic metals, and discovered that the reaction can't be driven by the hydrogen reacting as it was usually explained. He went on to work on that in lab with coleagues, wrote a paper and got published in Nature. It seems like science to me, and it was crowdfunded, that's what got me excited, because it could be used to fund research that's hard to get funded by traditional means ("is cool" is a different motivation than "is useful", so there may be many low hanging fruits). The more angles the better.

As for education - it won't replace theorethical lessons, but I think it's useful to see real experiments to develop intuition about how the theories play out in real life, how the quantities look like, what's realistic and what's not. Even with the RHNB which I agree is mostly entertainment - school physic lessons often don't allow me to predict the result of a given video. Yes it's most probably useless for my life, but so are most of the lessons I had in school. I like having the intuition about how everyday stuff behaves in extreme conditions. It's the difference between knowing that water can freeze, and seeing winter for yourself.

It's that part that was the most jarring hole in physic and chemistry lessons I had (we almost never got our hands dirty, and even if we did - it was done so fast that usually nobody got the experiments right, and there was no time to work out why for everybody, so teachers just moved on). And the stuff used in school experiments were "magical" ingredients that you wouldn't know where to get, and how to handle.

I envy the kids today that they can just look up "how to make sugar+saltpeter rocket". When I was a kid I tried it many times and it never flied (no textbook mentioned you have to have fresh dry saltpeter, or that you can dry old saltpeter in electric owen - it was just a formula and warning that could as well mean "burning 1 gram will destroy your home" or "burning 1 kg will be slightly inconvenient").

> (Thunderfoot seems to be a feminism/politics/atheism channel?)

That's why the GP is saying Thunderfoot's science stuff.

It's interesting when he try's this with aluminum foil:


My guess, he's not so much folding it as reshaping and mixing the metal under intense pressure in much the same way you might work dough ... (yeah, bad analogy... )

> much the same way you might work dough

No its a good one. Reminds me of how they made "Damascus" Steele by pounding different layers together.


Too bad aluminum is too soft for this technique to provide any advantages.

...or perhaps that should actually be tested. Would this kind of processing change the mechanical properties of aluminum in any significant way?

Funny. He actually calls it Damascus Foil in the video.

I missed that! Maybe it was subconscious.

You can see something like that being done here.


> What happened here? To be certain, I would need to repeat the experiment myself with a few more tools, like a thermocouple and an electron microscope. But I have a guess.

Someone please give this guy access to a hydraulic press, a thermocouple and an electron microscope. I want to see the evidence!

Interesting. I didn't know that the energy we can create with such a simple tool was enough to tear apart chemical bonds. In my head these bonds are somehow a few magnitudes stronger.

When you cut something with a knife or rip it apart with your hands you're also breaking chemical bonds. Some chemical bonds are weak enough that just normal light can break them apart. Stuff like Nitrogen triiodide decomposes whenever it feels like.

Stuff that has "nitrogen" in its name usually decomposes whenever it feels like, and humans generally don't like the results of that process - especially if they're standing nearby.

Fertilizer contains a considerable amount of it and can be handled fairly safely... Unless you get careless: https://en.wikipedia.org/wiki/Oppau_explosion

These bonds are about 1/1000th of typical chemical bonds, the article says.

Whenever you boil a kettle you're breaking the same hydrogen bonds which provide the water its surface tension.

Hydrogen bridges are intermolecular forces. The same kind we break every day when we break stuff by hand. (The strongest variety of them, but still not chemical.)

The interesting here is how they are broken, not that they break.

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