Old goat, I ran across this in my research about the number of plies needed. http://www.sheldonbrown.com/rinard/carbonqa.htm


I am planning a bamboo build(when the weather warms up). I am going to start with some lugs from an old Reflex MTB. It is a bonded aluminum frame. The lugs will be inserted into the bamboo then wrapped in the same fashion as other bamboo builds. I don't have pictures of my frame but is a link.
http://www.mombat.org/Reflex.htm
http://www.mombat.org/1990_Reflex_Limited.htm

Goat,

http://www.bmeres.com/carbonframe1.htm
From his website, "On the top and down tubes and seat tube, there are 9 layers; on the chain stay and seat stay there are 11 layers. The high stress areas were covered with additional 6-8 layers."

Renovo wooden frames weigh from 3.5 to 4.5 pounds. I took this photo at the 2008 NAHBS in Portland where Renovo had a complete bike hanging from a scale. It weighed about 17.5 pounds ready to ride.

http://i32.photobucket.com/albums/d7...CIMG4294sm.jpg

I spent an hour this morning wrapping the seat tube/top tube/ seatstay joint area with 6k carbon tow.
This is a MESSY job! I cut the tow into 2 ft long sections so that they would be easier to handle then I soaked the tow in epoxy and started wrapping. The first few sections went on nice and smooth but when I had to start making a figure 8 around the frame tubes it was impossable to be real neat. I got 2 layers on and it started to get ugly so I called it a day and wrapped the whole mess with cut up sections of inner tubes streached tightly. I'll see how it looks when I unwrap it tomorrow. I'm using Aeropoxy with 60 min hardener but the set up time is really slow in my 60 degree workshop. Tomorrow I'm planning on sanding off any epoxy ridges and adding a couple of more layers. Wish me luck!!!

^^^
Yep, composite bikes are not made of bamboo, carbon, flax, and the like. They are really made of rubber gloves.

Good luck.
Making them pretty comes from the finishing.
Don't get discouraged.

You ain't kidding about the rubber gloves! I'm on the second box of 50. After I unwrapped the inner tubes I found that the carbon tow actually laid down pretty nice. I sanded down the rough spots and added a couple of more layers of carbon then wrapped the whole thing in inner tubes again. I have been adding two layers of carbom tow each time and then sanding the hardened carbon between each application. I plan on doing a final wrapping with hemp string as a cosmetic layer. I'll post some pictures after I'm convinced that the frame is presentable.

He guys,

Just joined the forum and stumbled upon this thread.
I am not going to build a bamboo frame myself, but me and my buddy are probably going to purchase two bamboo frames from craig calfee, build them up with touring parts and go on a big tour. Cycle from Alaska to Argentina on bamboo bikes. Gonna follow this thread, might be interesting for me concerning maintenance and repair stuff...

I'd be trying to build my own frame. The extra 3000 saved could go a long way to help out on a trip. Of course if you have that sort of excess cash, lucky you.

Aah.. Well, we're not going to buy Calfees designer bamboo bikes from his workshop in the US (I wish). No, we are getting them from Ghana, where Calfee set up a 'franchise' workshop. There he taught locals to build bamboo bikes for personal use as well as export to US/EU. He put some quality/integrity tests in place to ensure top notch frames for bearable prices. Around 650 dollars gives you a 'touring' frame. I would have loved to build my own bamboo bike, but quality bamboo is hard to come by in The Netherlands. In addition, I am no engineer and rather work a week or two in a fast food joint to get the 650 bucks then spend months on 1, acquiring the right materials. 2, studying up on (bamboo) frame building and 3 , actually building and testing the bike.

I finally have my frame ready to assemble into a bike. I'm going to build it as a single speed so that I can test it for strenth. If it passes the test I will strip it down and do some fine finishing and mount a decent drivetrain. http://bikeforums.net/attachment.php...hmentid=137372

That's a damn fine looking first frame, OG.

Nice..

The frame is ready to test but the weather is not cooperating so it got a preliminary test on the trainer!http://bikeforums.net/attachment.php...hmentid=137807

That is the coolest F*&^ING thing I have ever seen! Bamboo bike frame? That sounds stupid but they look cooler than cool. WTF? That bamboo Mt bike frame is sick!

Took the bike on a 20 mile shakedown ride today. Nothing cracked,broke, or made any unusual noises! The thing rides and fits me great!
http://bikeforums.net/attachment.php...hmentid=140707

http://www.bikeforums.net/attachment...7&d=1268075349

That deserves to be seen full size.
Old Goat, that is a beauty.

That turned out really nice.
A tip that I should have mentioned is that you can dry wrap the carbon and make it quite a bit more manageable. Mix your epoxy and paint a layer over the lug area then wrap the dry carbon over the epoxy. It will wet itself by the epoxy squeezing up through it. Then when you've completed the wrap you can paint another layer of epoxy and then wrap it with the tubing strips.
I only went through 3 pairs of gloves so it is quite a bit neater.
Enjoy your ride.
I'll be posting my latest one soon.

Here are some pictures that I took during the build of my first bamboo frame.I learned alot from this project so the next one will be easier.

Here's my latest. Set up fixed but convertible to geared with addition of cable stops etc.
http://i399.photobucket.com/albums/p...h_CIMG5917.jpg
http://i399.photobucket.com/albums/p...h_CIMG5919.jpg
http://i399.photobucket.com/albums/p...h_CIMG5920.jpg
http://i399.photobucket.com/albums/p...h_CIMG5921.jpg
http://i399.photobucket.com/albums/p...h_CIMG5923.jpg
http://i399.photobucket.com/albums/p...h_CIMG5924.jpg
http://i399.photobucket.com/albums/p...h_CIMG5925.jpg
http://i399.photobucket.com/albums/p...h_CIMG5928.jpg
http://i399.photobucket.com/albums/p...CIMG5929-1.jpg
http://i399.photobucket.com/albums/p...h_CIMG5930.jpg

<p>Problem #1. Hi modulus (stiff) lugs or wraps of carbon, steel, or whatever joining low modulus (flexible) materials like bamboo or wood are a prescription for failure. The flexible material bends against the unyielding material of the connector and will ultimately fail at that intersection. Don't have to take my word, Calfee abandoned carbon wraps for that reason. They changed to hemp for a lower modulus connector, but the result of low stiffness materials throughout results in a flexible frame, duh. In any event, I doubt the hemp solved it, because the modulus of epoxy can't get down to bamboo.</p>
Problem #2. Bamboo or wood absorbs moisture naturally and that cannot be stopped by paint or oil finishes. The force of expansion due to moisture against an unyielding lug exceeds the proportional limit of the expanding material, causing the cells to collapse at the perimeter. When the moisture content decreases, as it does seasonally, the bamboo shrinks in the connector, loosening the joint. Eventually the joint will fail, not too eventually at that. Yeah, yeah, I know some Princeton engineer is doing this, he must have slept through the materials science classes, it's just elementary stuff.

Theory and science versus practical application. Know your materials and balance their strengths and weaknesses.
I can see how a totally unyielding Carbon/Epoxy wrap and poorly acclimated bamboo could cause these problems but the key is to get your bamboo down to maximum shrinkage and use an Epoxy and Carbon with a modulus that matches the Bamboo more closely.
The trend did seem to be towards "Aerospace quality high modulus carbon" and the absolute best Epoxy there was. Then I can see the disparity causing problems.
But in practice Epoxy/Carbon is nowhere near as unyielding as you seem to think. Particularly when the joint feathers into the bamboo and distributes those stresses over a larger area.
Many things are made from natural materials that undergo moisture and temperature cycling with a bit of care. Wooden Kayaks and Airplanes, Bamboo fly rods that are 100 years old and still going strong.
It takes very little extra effort to not leave your bamboo bike lying around in a damp environment or baking in a sweltering area.
There is also Epoxy designed for materials with different thermal coefficients.

I have just begun building a bamboo bike, and have already treated the bamboo. I have been looking at carbon fiber tow, and was wondering if this one would work:

http://cgi.ebay.com/ws/eBayISAPI.dll...#ht_1469wt_283

It lists the resin it uses, but I do not know if that affects the ability to use it with other epoxies. Also it is 12k, but I don't know if that will make much of a difference. Does anyone have any opinions on this tow? It much cheaper per yard than anything else I have found.

You don't need 5,000 meters of carbon tow....unless you plan on building like 5 bikes. I don't know about 12k tow, I've only used 3k. It might be a little bit harder to work with because it is larger.

Oh, I know I don't need nearly that much. It is just that the item above is by far the best deal on carbon tow I have found yet.

Just wanted to say that bike is freaking amazing.

I just built an accessory for the frame I will be building:

http://img404.imageshack.us/img404/1634/p5200098.jpg
http://img517.imageshack.us/img517/5245/p5200097.jpg

It is not quite finished yet, as I have not finished the bamboo, but I am really pleased with the way it turned out. At first I was worried about strength, but this bamboo easily supports much more than my weight. Clamping it to the stem has not been an issue either.

I did the same thing for my bike. Did you heat treat that bamboo? It seems to be less prone to cracking if you do, but it would also make it darker.

Yes, I heat treated it and then sanded it a TON. I am still a little worried about it cracking where it is clamped, so I might wrap around that area with carbon and epoxy once I get the materials, to give it strength in that direction as well.

You should soak the inside of the bamboo tube in Epoxy and put a piece of dowel inside the portion where the clamp goes. That will help support it there.
If the piece of bamboo is perfectly round it can withstand very high crushing forces if they are distributed evenly from all sides. It's a bit like crushing an egg by forcing in from either end.

Have you done that before? I wanted to try it, but couldn't figure out a good way to do it.