I built a bamboo bike frame over the summer. It's super fun, both to build and to ride. I was inspired by Brano Meres' excellent Instructable, ayasbek's Instructable, and, of course, Craig Calfee's bikes. My method is slightly different, so I decided to document it. Beware: I underbuilt the bottom bracket joint and it cracked; I'm currently looking at vacuum bagging to make the joints much stronger. I will update this Instructable once Bamboo Bike Mk. III is done (this one is Mk. II).

DISCLAIMER: If you try this, it's your fault if it breaks and you get hurt. Frame failures are no fun, and if you build this and your frame fails, it is very possible you will get hurt. Don't blame me.

The basic process will be:
1. Get materials!
2. Design the frame
3. Heat treat the bamboo
4. miter the tubes; the head tube and the bb shell will be metal parts that fit inside bamboo sheaths.
5. Tack it all together
6. Reinforce the joints
7. Build up a bike
8. Ride!

Step 1: Materials and Tools

Materials you'll need:
- bamboo, of the appropriate sizes. I got mine from OSH. They had " 1" Bamboo ", which in reality ranged from .75" to 1.25" in diameter, and " 1.5" Bamboo ", which in reality ranged from 1.25" to 1.875". I used .875" for the rear triangle and 1.5"-1.75" for the front triangle. It's definitely strong enough.
- hemp fiber, or fiberglass, or carbon fiber. I used hemp fiber from hemptraders.com. Fiberglass is cheap and available at OSH. You can get carbon fiber ( and fiberglass, too) at fiberglast.com .
- epoxy resin and hardener. 10 minute pot life worked well. I got mine from West Marine, and it's available at fiberglast.com too.
- 5-minute epoxy. Or 30-minute, or 2-hour, it really depends on how patient you are. I got them from OSH.
- a head tube and a lugless bottom bracket shell. I got mine from novacycles.com .
- dropouts. I got mine from ebikestop .
- expanding foam. I'm not sure if it is needed, but Brano Meres seems to think foam does good things, so I put some in the rear triangle. It helped keep the dropouts in their place when it was all getting tacked together. It's light and cheap, and I got it at OSH.

Tools you'll need:
- a propane torch, or a heat gun. This isn't necessary if you can breathe fire. It's for heat treating the bamboo. Mine is from OSH.
- a hacksaw or a coping saw. This is for mitering the bamboo, and for cutting the tube to length. Mine is from Home Depot, I think. You probably have one already, though.
- if you have a drill press, I hear you can get an attachment that holds a tube at an angle so you can miter quickly and accurately. thavinator posted this link in the comments which points you toward where you can buy them.
- a half-round wood rasp. This is for mitering the bamboo. Got it from OSH.
- tubemiter.exe . Invaluable when mitering. Mitering tubes. Not so useful for mitering other things.
- a Dremel. Useful for everything. I bummed one off a friend, but I was almost done with the frame at that point. This would have made things go much faster.
- disposable gloves. Epoxy is bad for you, don't touch it. Costco sells these in bulk. Your local drug store will carry them too.
- a mask; epoxy and sawdust and the like is bad for you. Don't inhale it. OSH.
- a jig. I got aluminum from OSH and built the almost jig by dr welby . Well, you technically don't need one, but I found it to be very useful. You'll also need clamps if you use a jig.
- calipers are nice to have. I "borrowed" mine from my school's robotics lab. Harbor Freight carries them cheap, though. Measuring tape is also important.
- a protractor is important to have. Angles are important to get right.
- a Sharpie, or something else that marks up just about anything.
- trash bags; they are useful for making the joints.
- scissors.
- a camera, so you can document your work.

You'll also need bike components. I bummed around and got some free, and bought some for cheap. Total cost of the entire bike: about $300.

Step 2: Design!

I CAD'ed my bike in SolidWorks, to make sure that I had clearance for everything. You can try to copy a bike you particularly like, or draw something out on paper. Then set up your jig according to your design. Simple, yet very important.

I don't actually know much about frame design. I did a little bit of Googling, a lot of looking at pictures of bikes, and a bunch of poring over the geometry charts published by bike companies. Then I used SolidWorks to check for clearance. You don't want to finish your bike to find that your pedals almost scrape the ground, or, worse yet, hit your rear triangle!

I "tested" my bamboo for strength by stacking bricks on it, sitting on the bricks, and then leaning to one side. It was so rigorous. My bamboo withstood about 300 ft-lbs of torque.

I found a picture online that has the names of the tubes of a bike frame. It may be useful to you.

Step 3: BB Shell, Heat Treating

I cut a short piece of bamboo to act as a sheath for the BB shell, and then used a rasp to increase the inner diameter until the bamboo fit over the BB shell.

Heat treat your bamboo first, as there is a little shrinkage that happens when you heat-treat. I learned this the hard way. When heat-treating, I found it easiest to have the flame be very small and be very patient. Heat treating strengthens the bamboo by caramelizing the sugars inside it, bonding the fibers closer together. It also looks nice.

Step 4: Mitering

This was easily the most labor-intensive part of building the bike. I had decided that using the joints from old bike frames was cheating, so I had to miter each joint by hand instead of just cutting the bamboo and fitting it on.

The seat tube is mitered to the seat tube at 90 degrees. Print out a template from tubemiter.exe, cut it out, tape it onto the tube, and go to town! First, I Sharpied in the line so that I could see the edge better. Then, I cut longitudinal slots down to the line, so that the bamboo would chip off as I sawed along the line. Then, I sawed along the line, and I finished with rasp work. After testing it against the actual piece I was mitering to, I did some more rasp work. And then tested again, and then some more rasp work. And so on, until I achieved a good fit. It doesn't have to be super tight, since you are tacking the two together with epoxy and not welding it, but it can't be *too* bad of a fit.

For the down tube and the top tube you will have to miter both ends, and they both have to be straight. The down tube will also have to be mitered to two tubes. My best advice is to be patient and careful. Use your protractor to check if your angles are the same in real life and in your design.

For the seat stays I used this calculator instead to make templates for the offset miters.

The bridges are very small, so they are hard to miter. I included pictures of how I did it.

Step 5: Tacking

Now tack everything together on the jig, with epoxy. Easy enough. Make standoffs for the jig as described in that instructable (but I used epoxy instead of welding it). I used string to tie the tubes to the standoffs, as I had no tube clamps and bamboo does not get attracted to magnets. It actually worked pretty well.

For the front triangle, I first tacked the seat tube to the BB shell.

Then I tacked the head tube to the down tube.

Then I attached the seat tube and BB shell to the upright part of the jig, and tacked the down tube/head tube assembly to the BB shell/seat tube assembly.

Then the top tube was slid in and tacked. For this, I actually had the front triangle (actually a front V at this point) lying flat on the table.

For the rear triangle, I filled the tubes with expanding foam first. I capped the ends with tape to hopefully force the foam to expand inwards. The seat tube was replaced on the jig upright, and the dropouts were bolted to the dummy axle. I put the rear triangle tubes into place, using the dropouts to poke holes in the foam, which held everything in place while the glue dried.

Tacking is the best, it's not very messy and your frame looks almost rideable! Don't try riding it, though, you'll just hurt yourself and your frame will be in pieces again.

Step 6: Reinforcing the Joints

This is the single messiest thing I have ever done, and also has probably contributed the most to my future cancer. Wear gloves, and wear a mask.

Masking comes first. If you haven't spread newspaper or cardboard all over your workspace yet, do so now. Use several layers of newspaper - this stuff soaks pretty well. Also, mask off the parts of your frame you don't want to have to scrape epoxy off of afterward.

If you've got vacuum bagging equipment, use that instead of this method I'm about to describe.

1. Cut up some strips of polyethylene (trash bags) and keep them handy.

2. Then get your reinforcement of choice (I chose hemp fiber) and break it into manageable chunks.

3. Mix your epoxy resin and hardener according to the instructions.

4. Soak the reinforcement in the epoxy, squeeze out excess resin, and plop it on your joint. Wrap it around and reinforce what needs to be reinforced.

5. Take the polyethylene strips and wrap them tightly around your reinforcement, so that you can squeeze out more excess resin. This will also help keep the surface fairly uniform.

6. Wait. Before the resin sets, but after it's no longer very sticky, take off the polyethylene.

7. Wait.

8. Repeat 1-7 until you are satisfied with the amount of material reinforcing your joints.

Step 7: Build Up the Bike!

Once you're finally done with all the messy stuff, cut the head tube to size and slide that into the bamboo sheath. Glue it in with epoxy. Glue in the BB shell. Don't get anything on the threads, it will be a huge pain to get the actual BB in if you screw up the threads. I used the leftover head tube stock to "shim" (a very very fat shim) the seat tube size down so normal seatposts would fit.

The rest is the same as a normal bike.

Step 8: Ride!

Get on your bike and move your feet in circles. Be happy. Don't die.
Credit me and tell everyone you meet how amazing I am when they ask about your bike.
Hello, Thanks for your tutorial wich helped me a lot! I can't say all I want to say, becausr I can't write very good English... however, I linked some pictures of the bigs steps of the project, hope you enjoy it. Greetings from Switzerland ;)
<p>Fun project. Thanks for the help.</p>
I just finished building my own road bike, take a look:<br> <br> <a href="http://www.cameronbrown.ca/blog/2013/01/how-to-build-a-bamboo-bike-part-1-plannin-things-n-fetchin-stuff/" rel="nofollow">http://www.cameronbrown.ca/blog/2013/01/how-to-build-a-bamboo-bike-part-1-plannin-things-n-fetchin-stuff/ </a><br> <br> <a href="http://www.cameronbrown.ca/blog/2013/01/how-to-build-a-bamboo-bike-part-2-cuttin-things-n-wrapin-it-up/" rel="nofollow">http://www.cameronbrown.ca/blog/2013/01/how-to-build-a-bamboo-bike-part-2-cuttin-things-n-wrapin-it-up/</a>
Do you know if carbon fiber fabric strips would work as well? I can't find a local source of carbon fiber tow. I'm in Singapore right now, and finding the materials is proving a little difficult.
I just did one using twine and got very neat and strong results. Basically just bathed the twine in fiberglass and wrapped it around the joints. <br />
Beautiful work!&nbsp; So how is this bike holding up now?&nbsp;&nbsp;Any concerns about durability?&nbsp; It seems like that would be the primary drawback to bamboo frames<br />
Looks great.&nbsp; Everyone thinking about building a bamboo bike should look at <a href="http://bamboobike.wordpress.com/" rel="nofollow">http://bamboobike.wordpress.com/</a><br /> <br /> There is plenty of detail on how to choose bamboo, how to make the hemp and epoxy joints (like calfee), how to choose bottom brakets, specifics about working with aluminum and steel, how to use an awesome online mitering pattern tool etc etc.&nbsp; Check it out.&nbsp; <br />
Nice, thanks for the link--is that a PVC&nbsp;frame jig in that pic?
Yep PVC, but there is more detail on at the site. <br />
My bamboo frame is cool. But it flexes soo much when I stand on one pedal or even torque the handlebars. Does your bike do this too? <br /> <br /> Anyone have an idea as to how to reduce this flex?<br />
Indeed excellent. This is one of the few real &quot;practical&quot; applications I've seen in green thinking. Now that's for sure renewable energy right there.<br/><br/>Though, the resin could have been furan (aka furane or furfuran) instead of epoxy. The metal pieces I understand, although there's a wood called Pockenholts (scientific name is Guaiacum officinale) which is one of the hardest woods there is. It's actually used as bearing brckets in the local steel plant. =) Ebony is hard enough as well to work as bearing surfaces, though it's pain i a** to work these woods.<br/><br/>Nonetheless, excellent DIY project. 5 of 5 stars from me.<br/>
Wow, I was wondering if there were any alternatives to the epoxy and the metal and you show up and tell me exactly what they are! Thanks! However I did a quick google, and it appears that furan is very hard to work with, "a colorless, flammable, highly volatile liquid with a boiling point close to room temperature" and "toxic and may be carcinogenic". Not to say epoxy isn't carcinogenic, but it is fairly stable at room temperature. Do you know how to work with furan as a replacement for epoxy resin? Also, the trees that yield extremely hard wood appear to be mostly endangered... so perhaps some good old steel isn't so bad? What do you think?
I used some kind of non-toxic carpentry glue and hemp string. The glue was about half the price of epoxy to boot. <br /> <br /> A chemical engineer told me that the two components of epoxy are toxic on their own but fairly safe once mixed and hardened. <br /> <br /> My problem is lateral flex. I have a lot of torsion around the bottom bracket when I stand on one pedal. Is this normal? Can anyone think of a design that would address torsion? <br />
I really don't understand about that metal thing... but hey if thats such bad thing for the environment maybe next time you can forge all the metal parts out of melting tin cans by the power of the sun? a magnifying glass maybe?
Making steel is a very dirty process, involving large quantities of energy and pollution (You ever been to a steel plant?) and making metals such as aluminum is even more dirty and energy consuming. The woods I suggested here are as hard (and sometimes harder) than steel, lighter than steel and they grow by thenselves. Is that what you ment?
yes exactly what I mean... sometimes under the great wheel of the green movement people don't actually make any sense any more.... from the look of this project it's impossible to replace all the metal part with whatever wood you are talking about. even if you could how much more time and skill would require for this project? let alone the tools that'd require for it...unless if there are company out there thats already selling the ready made parts out of wood. it's just seems really impractical I think it'd be way too expensive it'd most likely triple or quadruple the price for this project. It just seems really unrealistic to think that it's possible for our society to live with out metal. Unlike plastic, most metal are harmless to the environment and it's extremely easy to recycle. I am all for cutting down the energy consumtion for every product we make, but you also have to keep in mind that there is always the practical side that we have to think about.... after all the end product are used by people. if it has to come to a point that people can no longer afford it then we are just wasting our time.
Any carpenter or cabinetmaker can manufacture these parts, and there are tools and machines for it as well....
Actually...<br/><br/>I used to work in a plastics factory (mostly fiberglass construction for industry applications) and we also worked with a development project concerning Furan as resin in an environment project. As this project is largely classified as of yet, I can only tell you basically what I've said so far, but Furan IS in the works to be commercially available as a &quot;green&quot; option to polyester and epoxi resins.<br/><br/>The one thing with it as far as I am concerned, is that it gets a brownish color, and looks like crap unless it's painted or some such. And it smells rancid! =P The styrene fumes from the polyester resins are perfume compared.<br/><br/>Anyways. Furan, as a pure compound, is certainly what you describe, but it is a working resin to date, although hard to come by and fairly expensive as well. Give it a few years though....<br/>
Cool! Even more reason to be excited about the future!
&nbsp;Hi, first off this instructional inspired me, im now starting to build one. but i have just one question for you. how did you get the bottom bracket shell in. did you use a glue/resin? thanks. ill be using carbon tow (string)
wats OSH?
That would be Orchard Supply Hardware, <cite>www.<b>osh</b>.com/ <br /> </cite>
Hi,<br /> I'm planning on building &nbsp;one of these babies, and i was just wondering, how deep does your seatpost 'shim' go? is that what you are going to put the clamp on?&nbsp;<br /> thanks,&nbsp;<br /> Adie
coolest thing ever,&nbsp; i have seen on the green channel (year right green) when they used to still show stuff that was actually interesting when it first started about a company that creates bamboo bikes, but that was like for $7000, that totally turned me off to the idea, but with these easy steps i know i can do one myself, but i will probably do a BMX frame since i prefer those kind of bikes, thanks for the post, when end up doing it i will definitely link it to yours,&nbsp; thanks for the inspiration and for being green (minus the chemical epoxy, but i understand) :)<br />
im thinking that you might have had a nice stronger finish if you had used a bit more epoxy that sanded it down a little so it is nice and smooth then if you want you have have added a varnish of some sort
the resin in a composite material has no strengthening properties on its own. extra resin is just extra weight(though you dont want to starve the fibers of resin). you can sand, but sanding any further than the surface of the fibers, weakens the joint because the strength of these composites comes from the long fibers. if you sand into the fibers, you shorten them.<br />
"get your reinforcement of choice (I chose hemp fiber) and break it into manageable chunks." did you consider just taking a spool of hemp, making an initial knot, and keep winding tight, and brushing on epoxy as you went? I assume you used a whole spool of thread for the bike (do you know weight of hemp), and I assume that its much easier to work with than fiber/carbon sheets?
people use spools of carbon threads, but not cloth, as far as i know<br />
On a similar project I saw, the hemp joints were done a little larger than needed and then sanded down after they cured. This was a little more streamlined and also the look was just fantastic. Give it a try and see how it works. Great project.
A Zen-bike!! Never-mind 'be one with nature', you're gonna be one with the pavement! lol Very cool idea though.
Just a question about the &quot;test&quot; weight. Wouldn't velocity increase your actual weight through force/speed? I wouldn't know how to accurately figure that, something along the lines of weight x speed = force/perceived weight at contact point. I'm showing my calculative ignorance here but, just wonder how that all plays out? Great idea though and looks like a fun ride.<br/>
I've used a flexural strength testing apparatus (a machine that does pretty much what you were trying with the bricks) on different frame materials, including bamboo aluminum and steel. The machine wasn't calibrated, so the readouts were essentially unitless, however the results of each material could be compared with each other. The bamboo withstood the most amount of force out of all of the materials, which was impressive. It also sprung back into shape when the weight was removed (unlike the other materials). So not only would I not worry about the crash safety of bamboo, but I'd actually prefer it over the other materials. It deserves way more credit than most people give it.<br/>And as an aside, acceleration does not increase force. Rather force <em>causes</em> acceleration. Further if the force is constant the acceleration will be constant, not increasing. But if you're worried about crashes you should actually be looking at inertia, and more specifically inelastic collisions.<br/>
Depends how the seat is, and the g forces wouldn't be enough to increase his weight by all those bricks.
When moving on a bike, your only acceleration is parallel to the ground (unless you hit a curb or a pothole), so I doubt that the perceived weight/normal force increases. I'm not so hot on the physics either.
I was thinking in reference to impacts (which I apologize for not making clear). Potholes (big and small) and other road imperfections might cause quite a beating on the joints.
velocity increases I rather than F, acceleration increases F. So initially you will have an increase in F but in a static system you have the exact same F as you do in any other static state. The only change you should really worry about is when your acceleration is sharp. That could cause problems.
What type of hemp fibre did you get?
To stop the resin from getting in the threads, how about screwing in the cups from an old bottom bracket? Although most of them have a bit that sticks out an overlaps outside the BB - not sure if this would get in the way. I don't think the threaded plastic bit on the left of some cartridge BBs sticks out (Shimano BB-UN54 etc.). Or anything that would plug the thread up - a large rubber bung, taped up bubblewrap etc. - or instead of trying to block the whole thing you could press plasticine or blu-tack into the thread itself.
Or spray the threads with a mold release.
that's you right john!?
Well, info is risky. I'm glad this was published none-the-less.
great project tho btw.... I love the part where you put where you get everything from on the site.... I already got some bamboo this summer but I just don't have the place to build the bike tho. I also don't have a jig where did you get yours?
Yawn... go watch TV. Not much risk there.
did you know that constantly sitting by the TV can increase the risk of heart disease. I really don't know if you are being sarcastic or you are talking about yourself going to watch TV....
Nice job on the instructables. I wish I'd have known about this when I built my first one in 2008. You can see an independant review of the bike at www.lowcadence.com search his blog for bamboo bike by phil webb. One significant thing I've learned is that different species of bamboo give different ride characteristics. I am living in Thailand doing community development stuff, so the bamboo guru's here have helped me select which one to use. (I don't know what it is in English though.) My last bike was a road bike and the ride was superb. www.bamboobikemaker.com
I don't understand the need to "green" bicycles at all. Just by riding one, you're infinitely greener than any other mode of transportation. This is a fun project, but frankly, I'd be worried about people reproducing this casually. A failure at typical cycling speeds is enough force to get really hurt, even with a helmet. If you really feel the need to "green" out, recycle an old steel frame to a fixed gear. Old steel frames last 30 years+.
You can even recycle an old steel frame to a multi-speed bike! The possibilities are endless :)
Your &quot;miters&quot; are called notches or fishmouths, and the jig that would have made them much more easily is appropriately called a <a rel="nofollow" href="http://www.google.com/products?oe=UTF-8&sourceid=navclient&gfns=1&q=pipe+notcher&um=1&ie=UTF-8&ei=aoO7SonEIpWMlAfz98HBDQ&sa=X&oi=product_result_group&ct=title&resnum=1">pipe notcher</a> Beware the cheap ones if you plan to do any actual metal fabrication with them, and if you're not keen to spend the money on one yourself, look for someone who does roll cages or general fabrication, they should have one.<br/>
Thanks, that's going into the instructable for sure! I knew there must be a better way to do it...
electrical tape sticky side out also works to hold and compress the hemp/epoxy resin :)

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