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Carbon fiber question
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John Canfield
(jcanfield) - F

Locale: Cascadia
Carbon fiber question on 11/12/2011 11:25:10 MST Print View

I am interested in making bike panniers with carbon fiber frames in them. There is no major requirement other than shape. They will be flat panels and slightly trapezoidal.

My question is-
What is the easiest way to layup carbon in this simple application? Can you buy it in "finished" form?


Colin Krusor
(ckrusor) - M

Locale: Northwest US
Carbon frame on 11/12/2011 12:00:41 MST Print View

You ask about "lay-up". Does this mean that you plan to do the lay-up yourself? There are a few BPL members who have experience with composite layups, but you might get more detailed advice on a composites forum. People there could answer specific questions about prepreg tapes, vacuum bagging, etc.

It would be much easier, I think, to use stock carbon tubing for the frame. I think you could find nylon, Delrin, or aluminum joints in many configurations, or you could machine them yourself if you have access to the equipment. If you want flat composite panels, these can be purchased off the shelf from a handful of online suppliers. Sandwich panels with hex accordion spacers in aramid, carbon, or aluminum are available, as well as foam and balsa. They are all fairly expensive.

Edited by ckrusor on 11/12/2011 12:06:32 MST.

Dale Wambaugh
(dwambaugh) - MLife

Locale: Pacific Northwest
Re: Carbon fiber question on 11/12/2011 12:27:58 MST Print View

I haven't dealt with them, but this company looks good: Very expensive stuff!

If you are going to lay up your own, consider making channels (bumps) in the material rather than dead flat sheets, which can make them much stiffer for the weight. FYI, epoxy can be nasty to work with and some people are allergic.

Vacuum bagging is a popular technique, but with a flat panel you could do it with a squeegee and some sort of weight/press/clamp concoction. The idea is to end up with as little epoxy as possible-- a "dry" layup. It would be fairly expensive to do just a couple small panels. Kevlar is another material that would perform well. Do some searching on canoe and kayak construction and you will find all kinds of tips and techniques for laying up high tech fibers.

For the project you have in mind, some sort of thermoplastic or aluminum sheet may do the trick nearly as well. You could add a lot of lightening holes and work with basic tools.

John Canfield
(jcanfield) - F

Locale: Cascadia
carbon on 11/12/2011 12:52:51 MST Print View

Thanks for the great information. I'll look into making a vac. system. I have done a little lay up in the past, but thought there was a potential alternative that would be easier/cheaper for production.

Duh. Google.

warren mcclintock
(the_gr8t_waldo) - F
carbon fiber on 11/12/2011 22:41:46 MST Print View

a few years ago i bought a few rolls of carbon graphite (carbon fiber) in yarn form from aircraft spruce and specilty. in yarn, all the strands of carbon are oriented in the same direction.( not like woven mat'l at all! even if you look at arrow shafts, you'll see that they are woven as well)) i'm thinking this is what youre looking for as it makes incredably strong structures! the different sizes are just the thread count, per yarn. i was using it for a aircraft wing spar. and since the lay up was gravity assisted, it was relitivly easy for this. the yarn was mounted on a rack that allowed it to spool off..from there it ziz-zaged thru a home made bath of epoxy. and when it exited, it was about .124 dia and pretty well wetted out and could be layed into a mold. building stryofoam works very well for a mold . i haven't done any vacume forming so can't coment on that part.if you'd like more information i'd be glad to help as i am doing the same thing for a front pack- my project is on hold untill late spring. i should add that...there's nothing easy or cheap about grp projects. and unless well thought out, it will be heavy as well.

Edited by the_gr8t_waldo on 11/13/2011 15:21:19 MST.