Carbon Fiber "Weave" ?

Eric said:

Is the square weave pattern found on most carbon fiber components purely cosmetic or am I suppose
to believe it is kevlar weave? Is it a sticker that is clear-coated on the part (I have seen
evidence of this on a pre 1997 Trek 2300)? What is the origin of this weave look? Why do companies
feel the need for this cosmetic step (doesn't it just add weight)? And, what is the difference
between nude carbon that looks marbled (like the new campy record cranks) and the all flat black
carbon tubes? I own a 1997 Giant CFR frame that has a diamond weave cosmetic finish, a seatpost
that has a square weave finish and an icon fork that has a nude marbled carbon finish. Thanks for
any answers or any recommended websites on the topic. Eric

It's a fabric made out of Kevlar and/or carbon fiber, which is woven together into sheets. The
frame maker cuts the sheets into a pattern, impregnates them with a clear epoxy resin, and then
molds the wet fabric into a bicycle-shaped object. More or less. Thre's lots of information out on
the Web about this with photos, etc. The IHPVA Web site has quite a bit on this, and does Damon
Rinard's site.

www.ihpva.org www.damonrinard.org (or maybe .com)

Eric said:

Is the square weave pattern found on most carbon fiber components purely cosmetic

yes

Quoted message said:

or am I suppose to believe it is kevlar weave?

could be kevlar, but that's usually a markedly different color - mostly for visual contrast imo.

Quoted message said:

Is it a sticker that is clear-coated on the part (I have seen evidence of this on a pre 1997
Trek 2300)?

only if /very/ cheap.

Quoted message said:

What is the origin of this weave look?

before modern high density fiber laying techniques were developed, it was felt that this offered the
best, easiest route to reliable componentry.

Quoted message said:

Why do companies feel the need for this cosmetic step

customer expectations. some customers want to /know/ it's carbon!!!

Quoted message said:

(doesn't it just add weight)?

yes

Quoted message said:

And, what is the difference between nude carbon that looks marbled (like the new campy record
cranks) and the all flat black carbon tubes?

manufacturing route. the "marbled" look comes from small sheetlets of fibers randomly compressed
together - exactly like wooden particle board used in house construction - the stuff that looks like
it's made of large chippings. it's made on thin slices like ply would be made from, cut, then
bonded. the random orientation and thin ply provide a very difficult route for crack propagation.
same applies to carbon.

flat black is generally where there are thin full size unidirectional layers, with different
orientations per layer. this is typically what
is /under/ the woven cosmetic coat on components that have one.

jb

jim beam <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Eric said:

Is the square weave pattern found on most carbon fiber components purely cosmetic

yes

Yes and no. For a particular application, woven "bidirectional" cloth may be a better choice than
the linear "unidirectional" fabric. Also be aware that you're only looking at the top layer of what
may be many layers of a sandwich. It's up to the engineer (or marketing droid) to decide what "face"
is presented to the world.

Quoted message said:

Quoted message said:

or am I suppose to believe it is kevlar weave?

could be kevlar, but that's usually a markedly different color - mostly for visual contrast imo.

Kevlar (capitalized) is usually a brilliant yellow/gold color. If there's no contrasting color
evident, then I'd *doubt* there's any Kevlar in the outer layer. There could be some inside- but you
won't find out without cutting the component apart. This makes bike shop sales dudes angry.

Quoted message said:

Quoted message said:

Is it a sticker that is clear-coated on the part (I have seen evidence of this on a pre 1997
Trek 2300)?

only if /very/ cheap.

Yep- 3M makes preprinted vinyl with a carbon-fiber "look". You can make *any* frame look like
carbon! Personally I like wood grain, but to each his own...

Jeff