251–260 of 282 posts
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> As for things like plywood that use glue for the laminations...glue is the most expensive and important part of the product I've been using a lot of MDF lately, and it's interesting to think that it's just sawdust and glue. It makes me wonder: are there other fibers which could be used in a similar process which would yield better materials than MDF?
I think you just reinvented fiberglass and carbon fiber
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Does that not depend if it’s stainless or not?
I think that's only used for structures immersed in seawater. It's not that we can't design buildings to last longer, it's that you don't want to design a building to last two centuries when you know it's probably going to be torn down in 50 years no matter what shape it's in.
If a building is made harder to demolish than its neighbours it's got a better chance to survive. I plan plutonium-core concrete walls for my mausoleum to prevent future generations from interfering with it.
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Making steel is how we got here. Europe was decimating her forests for charcoal. England ran out first, then turned to coal, then needed to pump water out of coal mines...
Thanks for that history. Alas, no such thing as a free lunch.
Good reads, if this area interests you, are Fernand Braudel Civilization and Capitalism Vol 1: The Structures of Everyday Life and Vaclav Smil Energy and Civilization: A History.
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Since "table knife" means the typical dull cutlery knives (as opposed to e.g. steak or kitchen knives), I have no doubt that wood (hardened or not) can be sharpened like that.
Yeah I suspect they're comparing to cutlery knives out of the box - without any extra sharpening.
[0] as an example only a knife made out of plastic bottle material (should be PE): https://www.youtube.com/watch?v=3ZnT31JeBTg
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The heated compression step allows the cellulose to form hydrogen bonds with other cellulose fibers, which strengthens the wood and makes the epoxy redundant.
That's all? No additives during the compression? And nobody figured this out before?
I've been intrigued for a while about various modified wood technologies (eg hardened wood, transparent wood), but I'm always disappointed because it usually ends up just being a minor support structure for a very non-wood material (generally epoxy). This one shows a compression step, so maybe it's different, but I'd really like more info on whether this is actually renewable or sustainable in any interesting sense.…
I, too, would like to see "green" engineering. How to nicely tap in biosphere / organic material to make whatever we need. One old trick was hemp plastic.. I'm not sure what was bad about it since nobody tried it again since Ford made a prototype car body with it.
Guy in my state on YouTube has one and takes it to car shows, or used to. (https://www.youtube.com/watch?v=UhpIgM6TpwA)
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Yeah seriously, bury the plastic really deep away from water tables and forget about it. We clearly can’t recycle most of the stuff. Couple that with moving away from a frivolous use of plastic and I think we are golden. There are a bunch of abandoned mines miles away from substantial water tables. Fill those up.
We can’t figure out how to store a minimal quantity of radioactive waste in a purpose-built salt mine dozens of miles away from any small town. I have no faith that we can find places to store megatons of plastic waste.
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Good luck finding an oil rich asteroid. Or an asteroid with lush virgin hardwood forests. As far as I know there isn't a shortage of iron ore. This hardened wood is solving a problem that we don't have yet.
I believe one of the problems it solves is that steel has a tendency to erode over time. Hence major infrastructure failures. If structural elements can be made to the same strength as steel, using HW, which will not erode at the same pace of steel, than the expected lifetime of a structure increases and that is solving a real problem.
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The US can’t keep up with infrastructure maintenance as it is, let alone moving to materials with shorter lifespans and more maintenance
I don't think that the economy of wood is worse in the long run. It is quite much faster and cheaper to build with, and as long as it isn't allowed to be wet for long periods of time it also lasts indefinitely (there are wooden temples that are 1300 years old), and repairs are usually faster and easier than similar in concrete.
"At comparable ages and spans, smaller percentages of prestressed concrete bridges are classified "structurally deficient" than steel or timber bridges."[1]