monkey999's Journal: bamboo better than carbon fiber for most things

There have been a number of stories about both carbon fibre and bamboo in the news recently.
http://www.bamboobike.org/Home.html
http://www.bbc.co.uk/news/business-25833264
http://www.autoblog.com/2014/05/13/bmw-carbon-fiber-investment/
http://cleantechnica.com/2014/05/18/bmw-investing-200-million-triple-production-carbon-fiber/
So this is a post I originally made as AC, about why CF is usually a poor choice:
The real problem with 'wonder materials' is designers often don't know the basics of materials science and go for the 'strongest' material without even knowing what kind of strength they need.
There are 3 important kinds of strength:

• breaking stress This is the amount of force it takes to break a sample of a given shape and size.
• work(energy) of fracture This is the amount of energy it takes to break a sample of a given shape and size. Elastic, for example, absorbs a lot of energy by stretching before it breaks, so it has a high work of fracture, but most people wouldn't call it strong.
  It has a low breaking stress because the final force at which it breaks is low. This is where the myth comes from that 'spiders web is ten times stronger than steel' - it takes ten times the energy to break a given width of spiders web than steel, but the same is true for nylon.
• stiffness This is the amount a given size and shape will bend for a given force.

All of these are forms of 'strength' but materials that are strong in one are likely to be weak in another. For example anything that is stiff will bend by less before it reaches its breaking stress. W = Fs so it absorbs less energy before it breaks.
tldr: stiff materials generally are brittle - this isn't because they are "made poorly" but because of basic physics. It's the reason you don't make springs out of glass or walls out of elastic.
CF is an extremely stiff material - this is why its used in plane wings, where stiffness is much more important than breaking stress or breaking energy.
Most 'designers' - as opposed to engineers - don't understand any of this.
I remember when a co-worker excitedly told me he was buying a bike with a CF frame; bike frames mostly need to absorb shocks and only need to be moderately stiff. I groaned and predicted it would crack within a year. I was wrong - it took a month.
Surfboards don't need to be exceptionally stiff, but - like bike frames - need to absorb impacts and constant forces. CF is a stupid choice for them. Bamboo is tougher and is a far better choice.
For more reading I recommend http://www.amazon.co.uk/The-New-Science-Strong-Materials/dp/0140135979