can carbon be trusted..

Northwind

Flies are more challenging, and the permits are cheaper.

There was a brilliant post on Pinkbike, where an Easton designer got annoyed about anti-carbon chat, he basically steamed in like a bull and started destroying people Mainly I remember "Yes we do use a material which isn't well suited for mountain biking- it's aluminium. If it wasn't for the fact that not everyone can afford our carbon bars we'd stop making alu bars"

Anonymous

Well, there's the catch. Of course they want to sell more carbon bars, if they're going to make more money out of it.

ride_whenever

A touch cynical perhaps yeehaa...

Aluminium isn't really suited to bars, steel is a much more logical material to use after carbon as it has a FAR more sensible failure mechanism.

Anonymous

I'll fail your mechanism in a minute

joshtp

you don't have a good mechanism failing in you

Northwind

yeehaamcgee wrote:

Well, there's the catch. Of course they want to sell more carbon bars, if they're going to make more money out of it.

Well that's true Though I suspect they make an awful lot of money off the EA bars as well, selling to poor people, OEM users and carbon cynics.

ride_whenever

My mechanism is un-failable...

Andy!

yeehaamcgee wrote:

Fly fishing? Doesn't she prefer to catch fish :?

Seemingly not. I'll never understand female logic.

Bar Shaker

Fishing rods are made from carbon for the same reason everything else is. For a given flex, it can be made much lighter. For a fly rod, lightness is everything if you want to fish all day.

For years, they were fibre glass, so going to carbon was a logical step.

Captain Turok

I'm a keen angler an I use rods made by a company called Century.

They made a big deal about a process called autoclaving, this was apparently ment to remove any void areas (bubbles?) in the carbon.

Do any bike manufacturers use this or a similar process?

john_smith

Not certain bike manufacturers are using autoclaves but if a fishing company use them would have thought bike companies would use as well. Trek make some comments on their site about keeping void count as low as possible. All the big composites companies like aerospace and automotive racing F1 etc are using autoclaves because like you mention it reduces the voids and means there is a less chance of a fracture spreading through the part causing failure when under load. These guys development budgets make cycling / fishing industry look miniscule so if they use autoclave then its for a good reason and hope bike companies start using them if not using them already.

Andy!

I would hope so.

The autoclave does 2 things:

1. provides the heat to cure the epoxy resin. It will eventually cure at room temp but you want to do it at elevated temp to maximise the properties and raise the glass transition temp.

2. they are high pressure to consolidate the layup. This works in conjunction with vacuum bagging where you get as much air out as possible using non-stick bagging films and breather film and then the autoclave is essentially a pressure oven to further compress the laminate.

Without any consolidation you will get voids and poor bonding between layers which is very bad.

On Ones manufacturers certainly do, well kind of: http://www.on-one.co.uk/news/products/q ... ntain-bike

Their process reminds me of the helicopter rotor blade process which is unsurprising really as a blade is very similar to a bike frame.

supersonic

Yep, Trek OVLC advertised this for years now.

Bar Shaker

Vac bagging and auto claving were first used commercially by the surf and windsurf board makers in the 80s. What would have been a 7kg race board could be made stronger at 4kg.

The bag is pumped out meaning you have 15lb per sq inch compressing the wet resin and weave. The excess resin is removed from the work piece and then it is auto claved whilst still in its vacuum state. The finished product has resin no thicker than the compressed weave it binds and that resin is cured to a very high strength. That the fibres are closer to each other makes the weave much stronger as there is less shear moment in a cross section of the finished product. 'Pre preg' has further reduced the resin needed and has dramatically increased the strength as the resin binds the fibres at much more microscopic scales.

All of the Chinese moulded carbon bikes will be made this way and most of the hand made 'non monocoque' ones. Those that aren't made this way will be made from vac'd auto claved tubes that are then resin glued together by hand, so will be almost as strong/light.

njee20

Yep, Trek OVLC advertised this for years now.

Optimum Void Low Compaction? Get your acronyms right SS, it's OCLV ;-)