Any carbon fiber experts out there?

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I've been drooling over Velocraft's and a bunch of other carbon fiber low racers I've seen on the web for a while now and I'm starting to get that old familiar itch to try to put something together. First I'm interested in building a front-wheel-drive, low, but semi-upright seat commuter/touring bike with a u-joint above the steerer tube to decouple the steering and propulsion.

Does anyone out there know anything about carbon fiber construction techniques as they would apply to recumbent bike frames? I'm also looking for any literature or web sites that explain the hows and whys and whats of carbon fiber construction.

I have been to this site many times: carbon! (http://www.jjscozzi.com/) and it has been a big inspiration and source of info, but I need MORE!

Thanks,

TD

The best CF construction method to date is bladder construction with a female mold formed from a male plug to control the amount of epoxy resin in the CF.

"the best" is clearly subjective. Ease of construction and cost effective designs such as the Calfee Stiletto, and Lug-and-glue df's like the high-end Merlin Cielo, are examples of efficient cf construction. For homebuilders and one-off prototypes, molds and "bladder construction" is usually cost prohibitive and time consuming.

If the goal is quick and cheap it is best to bend a muffler pipe for the frame, weld 2nd hand bicycle frames or do a lug and glue construction with carbon. The end result will never be the same as a bladder construction frame. Johnny NoCom

By what pool, does your vast wisdom speak? Your a builder.. or... a structural engineer perhaps? And therefor qualified to say what is "the best" cf construction method for ALL designs? YES.. or NO? If not, your words are nothing more than personal speculation... and "pass the buck" links.

This latest bike is a speed missile and faster than a Stiletto with baloney bubble fairing or old school design Baron.

Oh really?... So tell me, what construction technique did the fastest bike on the planet employ for its cf frame?

PePe,
The fastest bike on the planet is the Varna which incorporated the male and female mold build system. No hack builder lug junk on that beauty. George Georgiev did not do the quick, cheap and easy build that most benters are satisfied with.

Cheers,
Johnny NoCom

Where's your bio?

Here we go again.... All talk and *appearently*... NO personal *hands-on* experience or design qualifications.

PaPa,
I suggest you goto this site to learn something.
http://www.kreuzotter.de/

Obviously you are in a coma and you have no clue to bladder construction or what builders have been using the bladder system. My guess is you ride some lugged TourEasy for the easy lifestyle of slow riding.

Cheers,
Johnny No-Come

More LINKS.... and no substance. All you *obviously* possess is a keyboard and the ability to cut'n paste.

Where's the beef Johnny NoCome?

Like it or not PaPa I know quite a bit about construction techniques. Cheers,
Johnny NoCome

And I know the difference between a digitally, self-taught phoney, and someone with last nights epoxy under his/her finger nails.

Cheers

Getting back to the subject of this thread, I have some questions for anyone EXPERIENCED with vacuum bagging of composite lay-ups.

I have a small diaphragm-type vacuum pump that I plan to use. I selected it over a rotary vane type pump for quiet operation and apparently adequate vacuum draw (22 inHg). The capacity is small, but for small stuff like bike frames I think it will be OK.

Questions:
1) does the pump need to run continuously or can it be turned off after the air has been drawn from the bag?
2) do I need to use a vapor/fume trap at the input side of the pump to protect it from epoxy vapors or is it generally not a problem?
3) what other little pneumatic stuff should I accumulate- valves? gauges, regulators, etc.?
4) can a pressure regulator be used in reverse to regulate vacuum?
5) I will try using a blue foam core at least initially. How does that stuff hold up under vacuum, or does it?

Finally, I was originally thinking that summer would be a better time to work on this stuff, but then I realized that the epoxy won't cure very quickly in cold temperatures, giving more working time. I plan to make a curing "oven" from either blue foam or cardboard boxes and put a heater inside. I figure once the lay-up is done and the bag pumped down and sealed properly I can then put it into the oven to cure. Is this a reasonable approach or am I missing something?

That's all for now...

Thanks,

TD

Tyler asked for "EXPERIENCED" help Johnny Nocome... that clearly disqualifies you.

Try these links Tyler:
Jim Scozzafava - www.jjscozzi.com/ (Excellent builder's resource)
Damon Rinard - http://www.sheldonbrown.com/rinard/
Portland John http://homepage.mac.com/john4bho/
Benoit - http://users.skynet.be/benoit.dery/

Hi tyler

I not going to say I am an expert,but I have built Quite a few carbon bikes.
(The mountain bikes I have made have been in races)
All made with molds. The proces is pretty simple, Design your bike make your mold plug, cast reinfoced plaster around to make the mold (reinforced plaster of paris with fiberglass window screen) I can give you more detail If you like.
I then bladder mold with bicycle tubes they are cheap and usually you can get old ones at the bike shop for free.
Some times I use vacume also my pump pulls about 27" and works well.
If you bag over foam crushing wont be a problem as long as you dont have hollow area's, atmosperic pressure on average is 14.7 pounds per square inch at sea level.I use lightweight clear bags from the hardware store.
My last recumbent frame I made the mold With a cnc router but not everybody has acces to one. It sure saved me a lot of time.

If you would like to see some of my bikes follow this link.
http://www.harnettcycles.com/index.html

Then click the bike website button on the right