Yes I have. Plug one end and pour Epoxy into the hollow. Let it sit and soak in for about ten minutes or so (depending on pot life of your Epoxy). Pour out the excess. Soak a pre-fitted piece of dowel and then slide it into the bamboo tube so that it ends up centered. Allow the Epoxy to cure. It is a good idea to cure the tube lying flat and roll it periodically as the Epoxy sets up so that it doesn't pool on one side of the tube. You can also cap the ends of the tube. You may just be able to fit some wooden nail or screw plugs which you can buy pre-made from any Home Depot etc.
That will give it a finished look to match the general natural look.
eta: Here's what i mean by screw plugs or "buttons": http://www.widgetco.com/wood-buttons

Haha, that's awesome. I'll see if I can find those.

Some great looking bikes in here. I'm planning a build right now. In fact I harvested some bamboo locally today.

I am also doing a preparation step that I haven't seen employed yet. I put the cut whole bamboo plants into water. This way they will continue photosynthesizing until all of their carbohydrates are used up. This is done in hopes to reduce chances of any type of microorganism thriving on my frame material.

Now I need a donor frame!

I've been working on mine for the last week, and now the frame is completely tacked and ready to be wrapped. The BB shell, dropouts, and head tube were all taken from an old steel Astrale frame. More pics to come soon!

http://img819.imageshack.us/img819/1272/p6090245.jpg


You can see the bobbin of CF in back to the right. It is freaking massive- I decided to go with the 5000 Meter roll of 12K Tow.

Make sure you work some glass into the BB and Head tube to prevent corrosion. Not sure it's as bad with Steel/carbon but it won't hurt. Looks like you may have been able to get a bit more insertion into the chainstays with your dropouts.
You can always build up an epoxy fillet with some fairing compound and blend that juncture before you wrap it. You can usually buy wood flour, chopped or milled glass, cotton fibers etc to make a thickened mixture to fill in areas and blend curves.

How close to the bottom bracket shell do you guys cut the chainstays off?

I gave it about an inch on the chainstays, including the lug. If I had done any more than that I would have had to cut slightly wider diameter bamboo, which would have cut down on wheel clearance.

I just recently built a bamboo frame. It turned out decent for my first one, only there is a little flex on the top tube and down tube so I think I need to use a larger diameter bamboo. Anyone know the best way to take off the existing fiberglass and epoxy/resin so that I can reuse the existing steel parts? Thanks in advacne

^^^
A drimmel.

I'm getting really close to finishing my frame. All that is left is sinking a shim for the seatpost and finishing the bamboo. What do you guys recommend to get a semi-gloss or satin coat? I'm afraid something traditional like polyurethane would be too brittle and crack.

http://img809.imageshack.us/img809/4596/p7050335.jpg

That's looking real good, TC.
I've always left mine unfinished (poly on the carbon, nothing on the bamboo) and I think Calfee uses spar varnish on his frames.

If there is no practical reason to clear coat it, maybe I'll just do a really fine sanding of the frame then.

The black bamboo I've used has a real thick silica skin, sort of it's own clear coat.
If you are going to sand the bamboo I'd coat it. Otherwise I'd just sand the lugs and coat them.

The black bamboo I've used has a real thick silica skin, sort of it's own clear coat.
If you are going to sand the bamboo I'd coat it. Otherwise I'd just sand the lugs and coat them.

Roughly how much carbon tow goes into one of these frames?

I always sand the bamboo(mostly to remove cosmetic blemishes) and coat the entire frame with Epoxy. Ideally that should be lightly sanded and coated a with a UV resistant Varnish as Epoxy breaks down under long term sun exposure.
I actually didn't bother with that with the first few frames since the total amount of time that a bike is in direct sunlight isn't necessarily that long.
I just wanted to get riding it. It can always be varnished later.
I would still recommend coating the bamboo in some way. It's very hygroscopic and the more stable you keep it the less stress you'll get on the frame through moisture cycling.
You can get a surfboard building epoxy that is more UV resistant and that's probably a good shortcut.
I figure it takes about 5 ounces of 6k Carbon tow to make a frame. Depending on your technique of applying it you may use much more initially and then sand a good deal of it away.

What sort of length does that come out as?

Also, would 12k tow work?

There is 1200 yards or so in a pound of 6k so you can do the math ;)
Many people use the 12k and honestly I think I'll go that route the next time. It's harder to wet out with Epoxy but it builds up faster.
The 6k can have you feel like you're trying to wrap something with dental floss.

The thing I would worry about for coating the frame with epoxy, is it being too brittle and cracking. Also, the West epoxy, with fast hardener specifically says that it is not intended for clear coating. West Systems does have a hardener though that is meant for this.

I used 12k tow, and I did not have trouble wetting it out. All I did was do a lot of fairly thing layers. I got 5000 meters of it, because it was relatively cheap in that size off ebay, and after finishing it looks like I have not even used any of the bobbin.

I though about using epoxy that way but if with some sanding and varnishing you are good to go, why add the weight of lots of epoxy?!
Just me.

Please comment on my project:
HERE

Epoxy suitable for wetting out composite material is not brittle. A carbon bike is technically a continuous Epoxy coating.
There would be no reason for it to crack or flake unless you actually break the frame. A thin layer of Epoxy does not weigh a lot. It's just easier to coat the sanded lugs and continue with the coating onto the rest of the frame.
I don't use WEST but the unsuitable for clear coating remark has to do more with the clarity of the finish. That's for when you build a wooden boat and want it to look like it's just wood.
When you're wrapping carbon lugs you want the slowest hardener you can get to allow more working time anyway.

I use tung oil, but I'm not sure if it has any UV protection.



Question: Does anyone think it would be possible to use bamboo in a fork? Would this result in certain death?

If you read Malk4vi4n's thread, he is planning on making one. I am looking foreward to that, as I am interested in doing this as well.

http://1.bp.blogspot.com/_urSQl6wUA5...booBicycle.jpg
It's doable, but I would not use it for more than coffee shop rides.

I've used a bike tube as a bladder to layer the inside of a tube with carbon to stiffen it. I would be worried about the amount of flex otherwise.

To clamp the seatpost, did you guys just clamp it directly to the bamboo, or did you sink a metal shim or piece of seat tube?

Piece of seat tube.
I scored the outside of it and roughed up the interior of the bamboo so the epoxy would have a good surface to stick.

So here is my bike:

http://img231.imageshack.us/img231/1307/img0290s.jpg

I'm seeing a lot of flex in the frame. Is this normal? Should I add another pole to the front triangle?

Flex is a problem with bamboo.
Try wrapping your chain stays with carbon.
Other than that there is not a lot you can do with this frame.
On your next frame use a larger diameter of bamboo for the main triangle.

It's a learning process and your next frame will be better than the first.
Having a first frame that is rideable is a great start.
My first is hanging on the wall with a shattered down tube.
It's a never ending experiment to build the perfect bike.

Bamboo requires Aluminum size diameter for optimum stiffness. Yours looks more like a steel bike.
I've never had a problem when using bamboo of larger size for at least the downtube.
The necessity of stiffening the rear triangle doesn't seem to be a problem. Short pieces of bamboo are virtually flex free. I shorten the chainstays as much as possible. The frame I posted has a rear triangle that's borderline too stiff.
I do select slightly thicker walled pieces for the drive side of the triangle.
I'll get some pics up of my latest.

I didn't have that much bamboo to work with. I just had to go with what was available.

I just bought another batch of bamboo, and the diameter on these ones are about 1.5 inches. Hopefully that will work out better.