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"Carbon Weave" fake?

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#21 ·
The thing about carbon fibers, as opposed to some other fibers, is: it does not stretch.

If you make a tube out of uni-directional carbon fibers and resin, it seriously does not want to stretch but you may be able to twist it. If you include fibers at an angle, as in woven carbon fabric or sock, it will also resist twisting.
 
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#22 ·
bigbore said:
they have to cover it with something due to the fact that it will disintegrate in the sun if you don't, and that could literally happen in a single year of riding.
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That's why they put a UV inhibitor in the resin layer, so it doesn't deteriorate itself, as well as what's underneath.

tomsmoto said:
in the context of the thread, hes asking if that layer is "fake" carbon weave. its certainly not, its straight up carbon fiber.
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It's real carbon, but wrapped simply because the real weave underneath is generally pretty ugly.

Dillontheman said:
Dont worry, the woven layer is real carbon fiber, but its more of an aesthetic layer than the structure. It serves two purposes:

1. Cosmetic Layer
2. Scratch resistance.
Thats all.

When Carbon fiber is woven, it is actually weaker than when it is unidirectional. Tomsmoto's post is wrong.

"Because carbon works best when resisting forces are in tension, unidirectional sheets are the heart of a structurally sound product. Woven fiber is used primarily as a cosmetic layer, because it provides very little structural strength."

I'll post pictures of both in a bit.
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Scratch resistance comes from the resin/gloss coat because that's what one is physically touching. The gloss enhancer is not used by companies like Easton.

The cosmetic layer is underneath that resin. The structural base carbon directly underneath.
tomsmoto said:
nope, its literally woven mat. the weave pattern gives it a lot of its strength.
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Incorrect. The cloth has little strength or utility for our purposes on its own. It's the combination of it and the resin that makes it strong. There are several different patterns and densities manufacturers can use, based on the needs for stiffness or flex. Also, more manufacturing tech is going into reducing such things as the amount of resin used and making it more consistent, along with compressing the layers more effectively.
 
#23 ·
tomsmoto said:
unidirectional carbon fiber provides... unidirectional strength. thats what you need for some applications, its not what you need for others. your statement is misleading, but nice try trying to call someone out ;)

a woven mat has more strength than your standard chopped mat mess of a composite. so yes, woven mats provide a lot of strength.. a big part of that is you have less resin and more composite. non woven mats hold a ton of resin, which makes a hard brittle weak layer.. but again, sometimes thats what you need for an application.
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I'll withdraw my last comment, as you and I are in agreement about these elements.
 
#24 ·
tomsmoto said:
unidirectional carbon fiber provides... unidirectional strength. thats what you need for some applications, its not what you need for others. your statement is misleading, but nice try trying to call someone out ;)

a woven mat has more strength than your standard chopped mat mess of a composite. so yes, woven mats provide a lot of strength.. a big part of that is you have less resin and more composite. non woven mats hold a ton of resin, which makes a hard brittle weak layer.. but again, sometimes thats what you need for an application.
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Mind telling me where you get your information from?

Carbon has phenomenal linear structural capabilities, wyhich means that it is incredibly strong in one direction, but struggles to support a load perpendicular to its orientation. The fibers work much like a load from a rope: if you hang weight from a rope it does a great job of supporting the load, but if you push on a rope, it will simply collapse. Imagine taking hold of both ends of a tube which has been built with carbon fibers running lengthwise, and trying to bend it in half. It would be nearly impossible because the forces on the outer part of the tube would be resisting your force in tension. Now take the same tube and grab a ball peen, and hemmer it. The carbon fibers will crack, because the hammer blow is a nonlinear load impacting perpendicular to the carbon fibers, which cannot resist the force as it does when the tube is being bent.

Go in and ask anyone who knows a moderate level about Carbon fiber, and they'll agreee with me.
 
#26 ·
Dillontheman said:
Mind telling me where you get your information from?
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i can has teh smart!

read what i said again man, im saying the same thing you are.. you're just trying to argue :lol:

grab a ball peen, and hemmer it. The carbon fibers will crack, because the hammer blow is a nonlinear load impacting perpendicular to the carbon fibers, which cannot resist the force as it does when the tube is being bent.
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theres videos on youtube of exactly this.. carbon frames being hit with a hammer from the side. they dont bend, or break. it holds more impact than an aluminum frame.
 
#27 ·
Maybe my example was the wrong one. Your saying the woven fiber is the main structure of the bike, whereas it is not, the main structure of the bike is multiple layers of Unidirectional carbon fiber, the woven layers are purely cosmetic. I'll post a picture of my father's S-works later.
 
#28 ·
Dillontheman:
I'm not sure about others here, but you are losing me with your argument. It looks like you are contradicting yourself, and agreeing with tomsmoto, yet trying to argue with him????

You seem to be arguing that carbon parts can only be strong in one direction, and like tom is saying, different mats and layups are intended for different applications. I did a lot of work with carbon in college. It's an amazing material, and people very often make genralizations about it that are completely untrue. Proper design, layup, compression while curing, etc can create parts with amazing strength in any direction.
 
#29 ·
in regards to the nanotube easton cranks and stuff...

nanotubes are, from what i understand, microscopic "crystals" of carbon that are attached to something akin to fiberglass. there's a skateboard company, insect skateboards, that uses nanotubes on several of their boards, and those too have the "solid" look as opposed to the carbon fiber weave pattern.

so, the nanotube pattern (or lack thereof) and the carbon weave pattern are essentially apples and oranges...similar in that they're both carbon-based reinforcing agents, but different in that they're...um...different.
 
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#30 ·
This thread is exactly why cyclists should not try to understand high-concept engineering principles, and just ride the damn things.

I see two people on this very thread that work in composites (one of them designs & builds composite bike frames!). And yet the loudmouth who read a product catalog (oh, I'm sorry, and whose dad owns a specialized) comes off as the authority. Typical.
 
#31 ·
I live in Wisconsin, which is the home of Trek, so I see a lot of dudes on mass-produced-but-still-well-manufactured crabon frames riding around, so I know as a fact that you are all wrong. The crabon is cut into strips and woven by blind sherpas from Nepal who have been transported to peru, where they chew on coffee and cacao all day and spit the juices onto the woven matt, which they then harden in kilns at no less than 20,000 feet of elevation for 5 years. Not only does this process produce an aesthetically pleasing, super-strong "woven" effect for Trek's proprietary OCLV crabon frames, it also allows you to just lick your frame for some instant energy when you bonk on the trail.
 
#32 ·
Dillontheman said:
Mind telling me where you get your information from?

Carbon has phenomenal linear structural capabilities, wyhich means that it is incredibly strong in one direction, but struggles to support a load perpendicular to its orientation. The fibers work much like a load from a rope: if you hang weight from a rope it does a great job of supporting the load, but if you push on a rope, it will simply collapse. Imagine taking hold of both ends of a tube which has been built with carbon fibers running lengthwise, and trying to bend it in half. It would be nearly impossible because the forces on the outer part of the tube would be resisting your force in tension. Now take the same tube and grab a ball peen, and hemmer it. The carbon fibers will crack, because the hammer blow is a nonlinear load impacting perpendicular to the carbon fibers, which cannot resist the force as it does when the tube is being bent.

Go in and ask anyone who knows a moderate level about Carbon fiber, and they'll agreee with me.
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That depends on how the carbon fiber layers are laid up. You can play a great deal with the strength properties with how the carbon is laid into the mold

-E
 
#33 ·
tomsmoto said:
i can has teh smart!

read what i said again man, im saying the same thing you are.. you're just trying to argue :lol:

theres videos on youtube of exactly this.. carbon frames being hit with a hammer from the side. they dont bend, or break. it holds more impact than an aluminum frame.
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Yeppers. I'm pretty sure that Dillontheman forgot that the fibers are layed out and it's the epoxy that holds the fibers in "tension" thus giving them their strength.

Anyways, there's all kinds of carbon fiber construction types from weaves dry or prepregged, chopped cf, nanotubes, and wound cf. They all look different too.

Also, there is a friggen huge move to fake or carbon look parts now, especially in the Pep Boys auto scene. Yall have seen the Youtube videos of how to paint fiberglass grey to look like CF? There's Youtube videos of how to epoxy single weaves onto car panels etc too, just so you can look "money" and such.

bigbore said:
they have to cover it with something due to the fact that it will disintegrate in the sun if you don't, and that could literally happen in a single year of riding.
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CF does not disintegrate, it is the material that it is suspended in that does, due to the use of cheapo poly resins. CF can stand up to thousands of degrees F, you know they make brake rotors out of CF right? It's the resins that hold it all together that have problems with temps.
 
#35 · (Edited)
Hello All,

I work in technical sales for a company that makes epoxy resin systems and urethane coatings for making preimpegnated CF and coating all kinds of composite products; commercial sports equipment in particular. I have been in nearly every composite manufacturing facility in China, Mexico and in the US. So I have some expreience and am somewhat knowledgable in composite fabrication.

A good portion of sports related products are made from unidirectioanal prepreg. Engineers design layup schedules that allow them to build in stiffness here, flex there, hoop strength, compression strength, impact resistance and a host of other desirable properties. On a bicycle once all of the flags of carbon are in place and have been cured the parts come out of the oven and are demolded and generally look terrible. They are then sanded which exposes the dreaded "pinhole". Pinholes are filled with rein putty and resanded several times if necessary. Then after some testing and QC inspections the part generally moves onto paint. A urethane coating is applied which protects the bare carbon part from UV degridation. After the base coats are applied the parts move to graphics dept. Where graphics are applied via screen printing ot some form of decal. Then back to paint for clear coat. often times designers will choose a graphic that depicts carbon weave or they will leave a window of unpainted carbon to show off the natural weave, if there is weave to expose.

Weather your carbon or carbon/ti/aluminum bike has woven graphic, complete paint or clear coated carbon is of no consequence. What does matter is the design, materials spec and quality of fabrication. Unfortunately you can have the best design but if the manufacturer is not babysitting the Chineese factory, more often than not the factory is sourcing cheaper materials and cutting corners in the manufacturing process. This is not a knock on Trek or Specialized, just a fact of doing business with Chineese manufacturers. If you want to see well designed and manufactured CF parts check out the fly rods made by RL Winston and Sage...unbelievable works of art in my opinion. It would be nearly inpossible to duplicate that level of quality in a Chineese factory.

That being said I am seriously considering buying a Specialized Rubaix road bike.

John
 
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