Hardened wood as a renewable alternative to steel and plastic • Hacker News Board

Re: Hardened wood as a renewable alternative to steel and plastic

#111

Post by zardo » Thu, Oct 21, 2021, 7:18 PM UTC

soperj wrote: post #94

canadian_tired wrote: post #64

Wood is renewable when you can grow it, cut it up into useful shapes, then at the end of its useful life, compost it. As soon as you add a shit load of processing and plastic and other stuff it's not "wood" anymore than gasoline is a dead dinosaur. As for things like plywood that use glue for the laminations...glue is the most expensive and important part of the product. Not the wood so much. Replacing steel? I don't…

It doesn't last so long in construction, rebar in concrete has like a 75 year lifespan no?

Plus or minus 25 years depending on the environment and maintenance. But I would disagree that 75 years is not so long.

Re: Hardened wood as a renewable alternative to steel and plastic

#112

Post by wffurr » Thu, Oct 21, 2021, 7:19 PM UTC

canadian_tired wrote: post #64

Wood is renewable when you can grow it, cut it up into useful shapes, then at the end of its useful life, compost it. As soon as you add a shit load of processing and plastic and other stuff it's not "wood" anymore than gasoline is a dead dinosaur. As for things like plywood that use glue for the laminations...glue is the most expensive and important part of the product. Not the wood so much. Replacing steel? I don't…

Exactly which step of this hardened wood process uses glue? I didn’t see that anywhere in the paper.

Re: Hardened wood as a renewable alternative to steel and plastic

#113

Post by ajnin » Thu, Oct 21, 2021, 7:20 PM UTC

EGreg wrote: post #69

canadian_tired wrote: post #64

Wood is renewable when you can grow it, cut it up into useful shapes, then at the end of its useful life, compost it. As soon as you add a shit load of processing and plastic and other stuff it's not "wood" anymore than gasoline is a dead dinosaur. As for things like plywood that use glue for the laminations...glue is the most expensive and important part of the product. Not the wood so much. Replacing steel? I don't…

Not to mention all that carbon released when the wood decomposes - no ?

Yes, that's why planting trees to offset carbon emissions is not really as good an idea as it seems, trees can live a long time but they're not immortal, and when they die they release their carbon back into the environment.

Re: Hardened wood as a renewable alternative to steel and plastic

#114

Post by wffurr » Thu, Oct 21, 2021, 7:20 PM UTC

sfink wrote: post #12

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.…

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.

Re: Hardened wood as a renewable alternative to steel and plastic

#115

Post by tedivm » Thu, Oct 21, 2021, 7:20 PM UTC

soperj wrote: post #94

canadian_tired wrote: post #64

Wood is renewable when you can grow it, cut it up into useful shapes, then at the end of its useful life, compost it. As soon as you add a shit load of processing and plastic and other stuff it's not "wood" anymore than gasoline is a dead dinosaur. As for things like plywood that use glue for the laminations...glue is the most expensive and important part of the product. Not the wood so much. Replacing steel? I don't…

It doesn't last so long in construction, rebar in concrete has like a 75 year lifespan no?

> In reality, their life span is more like 50-100 years, and sometimes less. Building codes and policies generally require buildings to survive for several decades, but deterioration can begin in as little as 10 years.

Re: Hardened wood as a renewable alternative to steel and plastic

#116

Post by icedistilled » Thu, Oct 21, 2021, 7:25 PM UTC

beambot wrote: post #44

oliwarner wrote: post #41

The graph in that composite diagram is really bothering me. Their "hardened wood" product is 23 times harder than "natural" basswood. When dried, basswood (aka lime) is an extremely soft hardwood. It's very popular with novice turners and hand carvers. When green (natural?) you can carve it with a stone. Species matters. Lignum vitae is 20 times harder than basswood.

Species matters, but so does availability. Lignum vitae is an endangered species, so it's not really a renewable alternative at the scale humanity requires.

fun fact, you can grow Lignum Vitae in SoCal in certain areas, not just in Florida. San Diego would probably grow lignum vitae well because it seems to like the random humid weeks in Los Angeles and just exists for the rest of the year

Re: Hardened wood as a renewable alternative to steel and plastic

#117

Post by adrian_b » Thu, Oct 21, 2021, 7:27 PM UTC

wffurr wrote: post #112

canadian_tired wrote: post #64

Wood is renewable when you can grow it, cut it up into useful shapes, then at the end of its useful life, compost it. As soon as you add a shit load of processing and plastic and other stuff it's not "wood" anymore than gasoline is a dead dinosaur. As for things like plywood that use glue for the laminations...glue is the most expensive and important part of the product. Not the wood so much. Replacing steel? I don't…

Exactly which step of this hardened wood process uses glue? I didn’t see that anywhere in the paper.

I have not seen the paper, but the process almost certainly does not use any glue.

It must use wood compression at very high pressures, which collapses the cell walls in the wood and results in a densified high-strength wood.

There have been various methods to make densified wood for structural applications, but I assume that this is an improved process, which makes an even denser and more homogeneous material, which ensures that even blades can be made from it.

Edit: According to Phys.org, the improvement over the previous processes is a treatment in a chemical bath that removes the lignin and other components of the wood, leaving only the cellulose, before the compression.

This removal of the non-cellulose components ensures that the densified wood is harder and with less defects than those made with the older processes.

Re: Hardened wood as a renewable alternative to steel and plastic

#118

Post by dreamlayers » Thu, Oct 21, 2021, 7:28 PM UTC

oliwarner wrote: post #41

The graph in that composite diagram is really bothering me. Their "hardened wood" product is 23 times harder than "natural" basswood. When dried, basswood (aka lime) is an extremely soft hardwood. It's very popular with novice turners and hand carvers. When green (natural?) you can carve it with a stone. Species matters. Lignum vitae is 20 times harder than basswood.

It is possible to make a knife out of lignum vitae: https://www.solidsmack.com/fabrication/lignum-vitae-ironwood...

So I guess the achievement here is that commonly available inexpensive wood can be made as hard as rare expensive wood.

Re: Hardened wood as a renewable alternative to steel and plastic

#119

Post by lindseymysse » Thu, Oct 21, 2021, 7:38 PM UTC

canadian_tired wrote: post #64

Wood is renewable when you can grow it, cut it up into useful shapes, then at the end of its useful life, compost it. As soon as you add a shit load of processing and plastic and other stuff it's not "wood" anymore than gasoline is a dead dinosaur. As for things like plywood that use glue for the laminations...glue is the most expensive and important part of the product. Not the wood so much. Replacing steel? I don't…

You can make steel with charcoal, which is carbon neutral in the end: https://aeon.co/essays/could-we-reboot-a-modern-civilisation...

What I like about this idea is it's a way to take carbon out of the air while manufacturing something. We are going to have to deal with carbon no matter what, why not manufacture things with it?

Re: Hardened wood as a renewable alternative to steel and plastic

#120

Post by adrian_b » Thu, Oct 21, 2021, 7:40 PM UTC

WalterBright wrote: post #100

spfzero wrote: post #70

Earlier quoted context omitted.

At least this material has a main ingredient that is renewable. No part of steel is renewable right? You can't grow more iron ore (though there is a lot of it lying around). Also I'm doubting "minimal processing" for steel. You have to dig up the ore with giant machines, transport huge amounts of it by train, smash it with a lot of energy and heavy equipment, melt it with a lot of energy and heavy equipment, etc., et…

> You can't grow more iron ore (though there is a lot of it lying around). We live on a thin crusty shell around a ball of iron.

The ball of iron would be Earth's core, and between the thin crust on which we live and the iron core there is the very thick mantle.

Nevertheless, the mantle is made of a mixture of iron oxides, silicon dioxide and magnesium oxide, with small quantities of the other elements, so under the thin crust, even if there remain thousands of kilometers until the iron ball, there is nonetheless what is essentially a huge amount of iron ore.