Bamboo Bike Frame.

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.

Comments

[snotty]

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?

Anyone have an idea as to how to reduce this flex?

[jentran]

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.

[rhysc]

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.

[Minneapolis Z]

Beautiful work!  So how is this bike holding up now?  Any concerns about durability?  It seems like that would be the primary drawback to bamboo frames

[mmann1123]

Looks great.  Everyone thinking about building a bamboo bike should look at http://bamboobike.wordpress.com/

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.  Check it out. 

[Minneapolis Z]

Nice, thanks for the link--is that a PVC frame jig in that pic?

[mmann1123]

Yep PVC, but there is more detail on at the site.

[ogion]

Indeed excellent. This is one of the few real "practical" applications I've seen in green thinking. Now that's for sure renewable energy right there.

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.

Nonetheless, excellent DIY project. 5 of 5 stars from me.

[xman]

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?

[snotty]

I used some kind of non-toxic carpentry glue and hemp string. The glue was about half the price of epoxy to boot.

A chemical engineer told me that the two components of epoxy are toxic on their own but fairly safe once mixed and hardened.

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?

[Duckism]

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?

[ogion]

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?

[Duckism]

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.

[ogion]

Any carpenter or cabinetmaker can manufacture these parts, and there are tools and machines for it as well....

[ogion]

Actually...

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 "green" option to polyester and epoxi resins.

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.

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....

[xman]

Cool! Even more reason to be excited about the future!

[rorymcstay]

 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)

[huntjulien]

wats OSH?

[lughaid]

That would be Orchard Supply Hardware, www.osh.com/

[adie.mitchell]

Hi,
I'm planning on building  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? 
thanks, 
Adie

[sumrandom1]

coolest thing ever,  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,  thanks for the inspiration and for being green (minus the chemical epoxy, but i understand) :)

[huntjulien]

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

[adie.mitchell]

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.

[godspiral]

"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?

[adie.mitchell]

people use spools of carbon threads, but not cloth, as far as i know

[DreamTheEndless]

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.

[Koosie]

A Zen-bike!! Never-mind 'be one with nature', you're gonna be one with the pavement! lol Very cool idea though.

[khan0000]

Just a question about the "test" 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.

[LaFeev]

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.
And as an aside, acceleration does not increase force. Rather force causes 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.

[Kryptonite]

Depends how the seat is, and the g forces wouldn't be enough to increase his weight by all those bricks.

[baslisks]

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.

[xman]

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.

[khan0000]

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.

[CrawdadMan]

What type of hemp fibre did you get?

[ac-dc]

(removed by author or community request)

[jeff2818]

You have got to be kidding. If you are on this site at all you must know that most anything home made will have risks. I think this Instructable is great. There are now commercial bike builders ( saw one on Green Network TV) using bamboo. They are very expensive. The techniques they used were the same. Please give this guy the respect he deserves . And, if you don't feel safe building one... DON'T!

[REDandroid]

Fear is innovations worst enemy. Let's be more realistic and more positive before we start telling people that what their doing is a liability. You can be hurt by anything! Doesn't mean you should live life in a bubble of "you could hurt yourself or your fellow innovators" I appreciate this site and i don't want to see anymore of these type of comments posted, it undermines the whole purpose of the site. Please!

[ac-dc]

Strange way to put it. I have no fear when I wipe out on my mountain bike, but I do acknowledge there will be some damage done (depending on speed and terrain). I recognize there is a risk and keep it in mind, and do not suggest to other people to do things that would likely pose substantial harm. You can't, reasonably, be hurt by anything at equal levels and it is crazy to think that because it is not a 100% safe world that some things need more care and attention than others. I don't care what you don't want to read. It does not undermine at all, it helps keep people thinking about SAFETY so they can assess their skill level before starting a project, have a better result, or spend their time on something else their skill level is more in line with, and most of all live to do another instructable another day. I am not suggesting it is the same type of liability as some, in fact the opposite I was suggesting that at least when people have a frame failure from one made by a professional, they have some recourse to sue, to get at least their medical bills taken care of instead of being bankrupt for life (since interest on medical bills can easily grow faster than a young person's income). Let alone the actual physical harm. REDandroid you seem to take lightly the harm that can come, and I think it is because you don't see a lot of people riding around on alternative material bicycle frames. This is not the same thing as making a rug out of drinking straws, a failure can easily put someone's head under a multi ton vehicle. Never wrote live in a bubble, you are making things up to pretend you have a reasonable position but it is never reasonable to make things up as if you can attribute them to someone who never wrote them. No matter how many times someone says life isn't safe, it is always reasonable for at least the first person to say "hey this is really dangerous people get crippled from far more rugged frames failing every day".

[cosmopuli]

ac-dc I have built a number of bamboo bikes using an instructable as my initial blueprint. I understand your concern for safety but, I have built a road bike, a beach cruiser, and a mountain bike using this method. The mountain bike that I use regularly is able to take big drops and absorb the bumps and crashes that come from regular offroad biking. Bamboo and carbon fiber tow/ or hemp are extremely strong and if used correctly make a beautiful and durable bike. If you were to do your due diligence and research the use of bamboo in the building of bicycle frames you would see that it is a safe alternative to traditional materials. Please do your research before making comments as you are spreading fear that is not based on fact. Any bike frame is capable of failure but, if built correctly bamboo bikes are some of the strongest most vibration dampening bikes I have ever had the pleasure to ride. If you are reasonably mechanically inclined and do the proper research you can build a safe bamboo bike that can handle all of the rigors of their steel, carbon fiber, and aluminum counterparts. It's as simple as that, make sure your joints are strong enough (overbuild them) and that your bamboo is properly heat treated and left to dry for at least a month and you will have a durable bike. Any bike can fail due to poor construction but, there is no inherent danger in using bamboo, hemp, and/or carbon tow to construct your bike. Take your time and don't take any short-cuts and you will have a beautiful bike. It is quite rewarding when people ask where you got your bike and you can tell them "I made it".

[REDandroid]

Hey no harm in warning people of potential failures from poorly constructed devices, but it is not cool to completely dismisses an invention as being completely dangerous. That is the interpretation that I got from your initial post. I apologies if I misread your meaning. I'm not the author of the bamboo bike, but 'my' interpretation was that he was not pushing this to be a replacement of your standard rugged aluminum or steel mountain bike, but rather a fun project. I could be wrong... I live in Portland, deemed "bike capital" of the US by some and there are literally thousands of homemade bikes here that are built 'safe'; it's the drivers of cars that you usually have to worry about :) There are the tall bikes where the rider sits 5 or so feet or higher off the ground that I feel are not quite safe. I was hit head-on last winter and taco'd my road bike. I'm sure the bamboo bike would have shattered pretty bad. Take care.