Composite material Guru help needed

[HobbyMan]

Maby someone on this forum here knows more about this than I do. (I am clueless)

Well, I don't know much about making composite materials. I really need to know what type of resin I should use for carbon fiber construction. I need something with a very high yield stress. Also, It can't be extremely expensive. I am working with carbon fiber TOW. I am doing a tension test on carbon fiber. I have a fitting that I machined that is essentially a cone with a hole in the end. The carbon fiber TOW goes through the hole in the tip and the individual fibers are spread out and set in epoxy. When the carbon fiber is pulled, they essentially wedge themselves tighter. My limiting factor is what epoxy to use. I want to do a tension test on carbon fiber, not the strength of epoxy.
So, if anyone knows what type of resin to use for carbon fiber construction and where to get it, that would be great.

If I get this carbon fiber stuff down, I might just try and make some motorcycle parts, sidecovers, fenders, etc...
Thanks

[dpotter58]

speaking of clueless, what means TOW?

[nubee]

Hey marinarius,
This is what you need to read:http://www.webbikeworld.com/t2/carbo...orcycle-parts/

[HobbyMan]

AS I understand it, a tow is a basically a bunch of unidirectional strands of carbon fiber.

[Ivan]

Being from the RC helicopter scene, I used a lot of carbon fiber. Vic Cambell in Springfield MO made some of the most tenacious heli blades ever on the market. They were notorious for chopping the heli to bits in a crash and still being flyable. Were talking a 1+ meter rotor span turning 2000 rpm (that's a tip speed in the 300 mph range) So you can guess there is a lot of force going on in a crash.

Anyhoot, I think the modern way to handle carbon fiber is the pre-pregnated stuff that you cook to cure. The resin to fiber saturation is much higher providing much better strength. While I know this is not easy for the average joe to do in his garage, it is the industrial trend.

Your idea is way cool. I would love to have some bullet proof side covers and a fairing that will break pavement if I ever lay it over. Maybe even a carbon fiber tank with increased capacity and some carbon fiber luggage that follows the same sleek lines. Ok, I am drooling now....

[50gary]

Hobby man you are correct on the TOW! Tows are usually for reinforcing strutcures, not normally to make complete end products entirely from tows. tows are good for reinforcement because carbon is strongest when used in long and straight runs. Fabric orientation is critical for optimum strength. Sometimes single strands are filiment wound but that is entirely different. Pressure vessels are often filiment wound carbon fibre. Woven fabrics are much more common for complete structures. I recieved your email and I'll respond tomorrow.
Cheers, 50gary

[50gary]

Hobby man you are correct on the TOW! Tows are usually for reinforcing strutcures, not normally to make complete end products entirely from tows. Tows are good for reinforcement because carbon is strongest when used in long and straight runs. Fabric orientation is critical for optimum strength. Sometimes single strands are filiment wound but that is entirely different. Pressure vessels are often filiment wound carbon fibre. Woven fabrics are much more common for complete structures. Actually the preferred ratio of resin to matrix is 30% resin to 70% carbon, any more resin is parasitic and only adds weight. The strength is from the fabric. Having said that the latest is carbon nanotube reinforcing additives, these microfil the gaps and are ultra strong. Carbon is actually quite brittle and not at all impact resistant. I use prepreg carbon, vaccum bag, and elevated temp. cure (oven) this is not simple stuff. I recieved your email and I'll respond tomorrow.
Cheers, 50gary

[latexeses]

Our local JC's engineering department participated in the "human powered vehicle" competition on a national level. Finished first against MIT and other high buck universities! The shell of the vehicle was carbon fiber along with other structural components.

Tap Plastics supplied the school all sorts of carbon fiber and kevlar components and supplied a bunch of know how as well.

A phone call to these folks can't hurt. They have been more than helpful whenever I had fiberglass questions.

It is their business...

http://www.tapplastics.com/

Rodger

[latexeses]

The Bike World article is pretty darn close to the way the shell was built at the college. We used a bag that had a valve in it though. It was also much bigger.

The builders used a hard foam and lots of sanding and cutting for the "male" mold for the shell. Also something Tap could guide you to find.

[fredintoon]

Hi Sailor,
Alas that technology has passed me by. Silly me, I thought that glass/polyester was high tech.
BUT, has today's use of tow any historical linkage to the practice of picking oakum?