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Crushed wood is stronger than steel

nature.com

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Re: Crushed wood is stronger than steel

#171

Post by ivanhoe »

washadjeffmad wrote: post #169
ivanhoe wrote: post #101

Earlier quoted context omitted.

Then you could just use a metal plate or glass, but we use the wood in order to protect the blade of the knife also. You'd have to re-sharp the chef knifes every few minutes if they were used on the surface harder than the blade.

You should, and it's called steeling. There's a foil edge on very sharp knives that will wrinkle and fold after use on anything, even tomatoes, making the knife feel dull. It's not, and it doesn't require removing metal as with grinding or sharpening, but you can steel to realign that edge or strop to hone it depending on the blade and angle. Even if you don't work with blades often, you've probably seen this depicte…

Obviously I meant the stone sharpening, not using the knife steel. And as for the material, many sources say that plastic actually contains more bacteria and that end-grain wood is more gentle to a blade than plastic. On the other hand plastic is easier to clean when it's new, but it's also more prone to cuts than wood and they quickly get dirty (at least in my limited experience). IMHO every board needs to be scraped or sanded from time to time to remove the top layer completely, that's the only way to keep it clean.

Re: Crushed wood is stronger than steel

#172

Post by Serow225 »

jacquesm wrote: post #144
Serow225 wrote: post #133

Earlier quoted context omitted.

I work at Red Wing Shoe Company, and our office has this type of flooring on the first floor: https://i.imgur.com/arWH5NR.jpg

That's gorgeous.

The labor cost to do it today would be substantial, I'm estimating it's around 4k-5k sqft of 2"x4" blocks!

Re: Crushed wood is stronger than steel

#173

Post by rjohnk »

gkanai wrote: post #150
brudgers wrote: post #86

Earlier quoted context omitted.

none of those ever made it to very high levels of industrial adoption. Non-exotic methods of strengthening wood, made it to high levels of production in spades: plywood, oriented strand board, microlam and glulam beams, and medium density fiber board (MDF) are direct examples. Wood I-joists and plate connected wood trusses are less direct. From a functional standpoint, standardization of lumber grades is a social tec…

Fire treated wood is called 'shou-sugi-ban' in Japanese and is occasionally used in commercial and residential applications. Fire treated wood has the benefit of being naturally fire-resistant, insect resistant, and water/rot resistant while also being a natural treatment (as opposed to a man-made chemical treatment.) https://shousugiban.org/ https://www.treehugger.com/sustainable-product-design/materi...

HGTV's Fixer Upper had an episode where this treatment was used. They were fixing up an old boathouse and decided to use this method for the exterior.

Re: Crushed wood is stronger than steel

#174

Post by coldacid »

jacquesm wrote: post #91
brudgers wrote: post #86

Earlier quoted context omitted.

none of those ever made it to very high levels of industrial adoption. Non-exotic methods of strengthening wood, made it to high levels of production in spades: plywood, oriented strand board, microlam and glulam beams, and medium density fiber board (MDF) are direct examples. Wood I-joists and plate connected wood trusses are less direct. From a functional standpoint, standardization of lumber grades is a social tec…

Yes, engineered wood is a mainstay of construction. But all of those processes were and are set up to be able to process a large volume in a relatively short time and leave very little to no waste, and what waste there is is sold off as fuel. Plywood - especially the higher grades - is amazing stuff. I visited a plywood factory in Ontario and it really opened my eyes to how clever and precise the manufacturing of var…

Where in Ontario? This would be interesting to see for myself.

Re: Crushed wood is stronger than steel

#175

Post by freehunter »

pbhjpbhj wrote: post #135
freehunter wrote: post #130

Earlier quoted context omitted.

If we're disregarding proper maintenance, almost anything can be biodegradable too. Steel will easily rust into dust in an alarmingly short period of time, but we have 100-story buildings made of un-rusted steel lasting for a century and maybe centuries more. Compared to cars from 5 years ago rusted into oblivion even while they're still being driven.

Rusting isn't biodegrading, it's chemical. Of course the lines aren't distinct, but they seem much clearer than you're suggesting.

In this case I don't think it really matters. No one says "my car is fine, it's just rusting not biodegrading". What matters is that the car is disappearing right before your eyes through natural processes that could have been prevented with normal maintenance.

Wood, when properly taken care of, lasts forever. Steel, when properly taken care of, lasts forever. Each of them will degrade without proper maintenance, and oddly enough they both have basically the same maintenance needs. Keep them dry, otherwise oil them occasionally.

Re: Crushed wood is stronger than steel

#176

Post by samstave »

jacquesm wrote: post #164
milesvp wrote: post #154

Earlier quoted context omitted.

I too was surprised to find out just how much variety and quality of plywood there is. I always thought it was a relatively cheap, kind of crappy alternative to good lumber. But since I've started following hobby laser cutting, I've been finding out that good plywood really makes a difference if you want good results.

I've had really good experiences with birch based plywood of the better grades and for heavier applications a grade that is used in construction to make the forms for concrete casting.

Plywood: How it's made;

https://www.youtube.com/watch?v=xGnr8ATHHX8

Re: Crushed wood is stronger than steel

#177

Post by jaclaz »

Something1234 wrote: post #25
jacquesm wrote: post #8

Earlier quoted context omitted.

Engineered wood has been a thing for over 100 years. Wood has a lot of desirable properties that make it a good construction material (fire resistance for instance is much better than steel). This article is definitely missing the wood for the trees to some extent, but it is an interesting development and even if the gain isn't going to be quite as large as indicated and there are some serious questions about whether…

How is wood more fire resistant than steel? What are the metrics used for this?

The way a wooden structure behaves is very different from the way a steel (or steel reinforced concrete) one behaves, as the materials itself behave very differently.

Let's take as an example a "main" wood beam to support a normal floor (or roof).

It has been calculated to be sufficient with a cross section size of (say) 20x20 cm ( Width by Height, in some countries "square" wooden beams are normally used, in some other countries sizes with width half the size of height are commonly used), the dimensional calculation takes into account "exceptional" static loads, like snow (if a roof) or crowd (if a floor), and dynamic conditions (like earthquake) so they are over-dimensioned in normal use.

What happens in a fire is the same as if you were reducing the cross section by scraping some materials off the foot amd sides of the beam, let's say removing 5 mm at a time, so , after some time the cross section will be 19x19.5, and then 18x19, 17x18.5, 16x18, 15x17.5, 14x17 etc.

What gives a value of the resistance of a wooden (or however homogenous material) beam is its moment of inertia that is expressed in cm^4 and equates to WxH^3/12, so progressively you have:

20x20^3/12=13,333

19x19.5^3/12=11,740

...

If you graph it, you will see a progressive decline of resistance proportional to the reduction of the cross section.

Also you have to consider how carbonized wood (char) represents in itself a "defense" of the wood against fire, once the first layer of wood is carbonized by combustion, it becomes harder/slower to burn:

http://www.mace.manchester.ac.uk/project/research/structures...

Here a graph of charring rate is given:

http://www.mace.manchester.ac.uk/project/research/structures...

In practice, any wooden structure is fire resistant for 30-60 minutes, and the solution for increasing the fire resistance (if the wood cannot be protected by other means) is simply that of increasing the cross section.

"Modern" wood, like composite beams, plywood, etc., may behave differently given the presence of glues/resins, etc.

With steel the resistance is given by its tensile strength, that decreases very rapidly from around 300-400 C (easily reachable in a fire and roughly equivalent to the ignition temperature of wood):

https://www.steelconstruction.info/Fire_damage_assessment_of...

Re: Crushed wood is stronger than steel

#178

Post by jpgleeson »

euroclydon wrote: post #39
jacquesm wrote: post #6

The most expensive wooden floors have the end grain exposed facing upwards and this is then compressed down, much like the top of a good quality butchers block. Those floors are just about indestructible. The heavier such floors are used the stronger they get! The wood in the article is compressed crosswise to the grain (so they get thinner rather than shorter), using the original planks as the raw organic material t…

Do you mind sharing a picture of this done right? The end grain wood floor pics I found on Google look mostly hideous to me.

The entrance to Trinity College Dublin is an 18th century gatehouse where the floor is made of hexagonal wooden blocks that have weathered quite well.

Re: Crushed wood is stronger than steel

#179

Post by rootw0rm »

theoh wrote: post #157
noir_lord wrote: post #151

Earlier quoted context omitted.

It is, the WWII Mosquito Fighter-Bomber was made from high grade ply and it flew faster than contemporary aluminium fighters, was incredibly durable (except for some de-lamination problems in hot humid far-east environs) and was actually stunningly beautiful.

Also mostly plywood: the Spruce Goose https://en.wikipedia.org/wiki/Hughes_H-4_Hercules

Haha, that was the first aircraft I thought of too!

Re: Crushed wood is stronger than steel

#180

Post by jacquesm »

coldacid wrote: post #174
jacquesm wrote: post #91

Earlier quoted context omitted.

Yes, engineered wood is a mainstay of construction. But all of those processes were and are set up to be able to process a large volume in a relatively short time and leave very little to no waste, and what waste there is is sold off as fuel. Plywood - especially the higher grades - is amazing stuff. I visited a plywood factory in Ontario and it really opened my eyes to how clever and precise the manufacturing of var…

Where in Ontario? This would be interesting to see for myself.

Thessalon iirc on Hwy 17.
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