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Comment by sfink | Hacker News Reader

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.

Very reminiscent of the supposedly renewable & sustainable bamboo products that are anything but. I love bamboo, but flooring should make you think "plywood" not "waving groves of fast-growing giant grasses". It's another glue and epoxy thing.

Update: https://phys.org/news/2021-10-hardened-wooden-knives-slice-s... is a much better source.

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Curious about your opinion on bamboo products. I assume you're referring to modern bamboo desks, shelves, and other items that are made from Chinese bamboo and made in China. They typically slice the bamboo grass pieces into ~8 sections, then use planing machines to create planks※. These are then pressed and glued together to make products. These products are then shipped overseas using the same methods as other products.

If the glue used is either sustainable or they don't use very much of it, and the bamboo is grown locally, what makes it less sustainable than using wood? And certainly more less energy-intensive than steel.

※ I am not a woodworker, don't know terminology.

The usual complaint I see against bamboo products is that they use hard bamboo that grows like trees, but promote a sustainable image based on the idea of soft bamboo that grows like grass. I haven't heard it's less sustainable than wood, just not any more sustainable.

Kg of wood per hectare-yr would be a good measure of how much useful wood is created, and also how much carbon is locked up in it.

Time is a critical factor (ie, the "yr" in your metric). Bamboo grows _incredibly_ fast.

density (a critical factor of hardness) is normally inversely correlated to growth speed. Faster growing woods/plants are softer.

It takes 4-5 years to grow according to the article, and you can make Strand Woven Bamboo out of it. You can get a feel for the hardness of Strand Woven Bamboo here:

    https://planettimbers.com.au/2014/06/25/timber-wear-tear-and-hardness-including-janka-ratings/

Quoting:

    "Even though a Janka rating of 8 is considered ‘hard’,
    many Australian timber species achieve ratings of 12
    and above."

Strand Woven Bamboo has a Janka rating of 14.

As it happens I live in Australia, and so have tried to bang the odd nail into an old house, which are often made from Australian hardwood. Almost all of us live in new houses made from pine, and so all make the same mistake. If you are lucky, and after more than a few bent nails, some old codger will take pity on you and tell you it isn't possible. You have to pre-drill.

Soft bamboo (which is useless for products like these) grows incredibly fast.

Why can they not be hardened? Or otherwise used?

Different species. Bamboo is actually a family of 1,400 individual species, not one individual plant. The grassy and woody varieties are just different plants with different material properties.

As a general rule, the structural properties of wood can’t really be changed without just injecting a shit load of petroleum products[0], which isn’t really what we’re after here. If a type of wood, bamboo or otherwise is too soft for an application, then there really isn’t a way to “harden” it. This is the reason we tend to use hard species for flooring, such as oak, as you need to rely on the natural characteristics of the wood for strength and hardness.

0 - For example OSB, which is basically 5% oil by weight. Even still, our ability to adjust some properties is limited. OSB is strong and cheap, but it’s not that much harder than the wood species it was made from, and hardness is a desirable property for flooring to resist dents. Also, OSB is ugly.

Some good photos of the process here[1]. The figure that's generally quoted for the time it takes for a mature timber bamboo culm to grow from a shoot to ~20m to be harvested is 3-5yr. Obviously each one is small compared to a large tree, but a stand of bamboo can produce a lot.

1; https://www.bambooimport.com/en/how-is-bamboo-lumber-made

That's an amazing link, with unadorned and unpolished shots of the factory where the bamboo lumber is made. Very interesting.

Well, the glue is a renewable resource, old livestock and milk. That's why Borden used mascot Elsie's spouse Elmer as a glue mascot.

https://en.wikipedia.org/wiki/Animal_glue

https://americacomesalive.com/elmers-glue-the-surprising-sto...

I'd be very surprised if animal glue was used in any engineered wood. Even in fine woodworking it's a niche product; it's expensive and generally doesn't work as well as other glues.

On the other hand, it is reversible. https://woodworkingparts.wordpress.com/2010/08/17/hide-glue-...

"The significant disadvantages of hide glue – its thermal limitations, short open time, poor gap filling capability and vulnerability to micro-organisms – are offset by several advantages. Hide glue joints are reversible and repairable. Recently glued joints will release easily with the application of heat and steam. Hide glue sticks to itself, so the repairer can apply new hide glue to the joint and reclamp it. In contrast, PVA glues do not adhere to themselves once they are cured, so a successful repair requires removal of the old glue first – which usually requires removing some of the material being glued."

What % of engineered bamboo flooring is stuff other than bamboo (like glue)? From looking at the side when installing it, it seemed like very little.

Quite a bit actually. Bamboo cant be cut into planks, so it's typically ripped into really thin strips and then laminated.

Even then it's little enough that I haven't been able to discern the glue even after close inspection.

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.

They even made a film with this car. It's called: Up in Smoke.

The Trabant - a classic example of cheap East German engineering. Woefully crash 'un'resistant, and a body made of cotton.

Guy in my state on YouTube has one and takes it to car shows, or used to. (https://www.youtube.com/watch?v=UhpIgM6TpwA)

As an aside, the article mentions:

> After the material is processed and carved into the desired shape, it is coated in *mineral oil* to extend its lifetime.

I was thinking how, surely, mineral oil isn't food-safe and well-fit for use on a utensil. However, it turns out that while low-grade mineral oil is proved carcinogenic, the high-grade version is not believed to be so, unless dispersed in a mist. And apparently, we consume quite a bit of mineral oil due to it's use in the baking industry (though that figure comes from 1961)

https://en.wikipedia.org/wiki/Mineral_oil#Food_preparation

Mineral oil can be found in most pharmacies marketed as a laxative. It's a common oil to use for cutting boards and other applications in proximity to food.

Right, another instance of where the mineral product is to be much preferred over the so-called natural one is with turpentine.

Mineral turpentine is to be much preferred over the natural one because the latter contains organic wood terpenes many if which are toxic and proven carcinogens - after all it stands to reason that they're dangerous, as trees have evolved to produce them to fend off or poison insects that attack them.

I find it somewhat distressing to see so many carpenters and woodworkers using terpenes-laced turpentine because they believe 'natural' is better.

It's time this dangerous myth was dispelled.

It depends on what you mean by mineral oil. Without definition it's about as useless as saying I've painted something in 'color' rather than specifying what color one used.

Whilst flammable, and for the simplest ones, even explosive - most small straight-chained alkanes as often found in mineral oils are reasonably innocuous in that they're not considered organically poisonous (at least in small amounts), however that can change greatly the moment you add certain additives to change their properties (as is often done in commercial products).

The most notorious and outrageous example being when Thomas Midgley Jr added tetraethyllead to gasoline/petroleum in the 1920s thus managing to poison most of the population to at least some extent.

Since the article talks a lot about replacing small plastic utensils, it seems plausible that they're not targeting structural applications at the moment, so the point about glue could be moot.

But will we see a wooden laptop?

Reminds me of the one video I saw of this man spraying different things with some sort of polymer that was virtually unbreakable. He'd spray a cinderblock wall and then hit it with a sledgehammer. The wall would break, but the polymer would hold... so yay?

That said, It seems like the sort of thing you'd want to spray asphalt shingles with.

Rhino shield probably

https://www.youtube.com/watch?v=DWkYRh6OXy8

Remember that everything that's always outside will be subjet to death by the sun.

Well it didn’t involve any epoxy, just a chemical bath in readily available chemicals and a pressure step. The energy requirements seem significantly lower than steel processing.

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