bamboobikemaker

Funny how so many folks discover bamboo to use for bike frame building. I had the idea a while back while bike riding in Asia, only to find out they've been around over a hundred years.

Why haven't they caught on in the industry?

I'm hoping now is the time. We've been working toward building a business to bring respectable jobs and skills to folks in the developing areas of south east Asia.

PhilNYC

bamboobikemaker...that is a seriously beautiful bike!

noglider 

Is it feasible to mass produce bamboo bikes? If you have a bamboo farm, you can choose the stalks you want, but how well can you control the width and thickness? Using metal that you can melt, you can shape your materials to your needs with very little waste. So maybe that's why there isn't a big bamboo bike industry.

Old Town

What kind of durability can you expect from a bamboo frame? I picture the joints working and grinding themselves to sawdust. Or are they captured in such a way they cannot work (move).

I have spent a good bit of time in the South Pacific and do not remember ever seeing or hearing about a bamboo bike. Of course I was not looking for one as I did not know they existed. Venture to guess what kind of useage is prevalent in certain Asian nations?

The pictures presented on this forum do not betray anything really different to the casual eye. I can see how I could have missed such bikes if I did not have my hands on one.

PhilNYC

My understanding is that most of these bamboo frames use some kind of carbon fiber wrap to secure the joints.

Allen

The lugs are built up on the frame out of carbon or hemp fiber usually.

bamboobikemaker

Durability is superb for a well engineered frame (including the species, age, and treatment)! Each frame is hand built, so the automated mass production is what I believe keeps the big boys from venturing here. A good set of calipers can tell you where to cut for the diameter your looking for. However, the culms are not always round, you just have to adapt and use this to your advantage.

bamboobikemaker

you can see a youtube of my project by searching for "bamboo bike by phil webb".

Contour

Hey guys, I haven't given up on this project and plan to finish during my break between semesters.

The things I am currently thinking and wondering about are, which hemp fiber, raw, sliver, or a twine? Or should I just go carbon, and if so I have seen conflicting information. Some say to use tow and to just wrap, others say that a weave would be much stronger. I have also been thinking about taking a bike and just chopping it and slipping the bamboo over so I don't have to worry about alignment issues the first time around.

Allen

The raw hemp fiber will work the same as the finer fiber. I am now under the opinion that twine may leave air pockets or pockets of resin void of fibers. I think you can make a stronger product with fiber (make test pieces and destroy them to draw your own conclusions).

I personally find TOW line is easier to work with than cloth. I am unsure the differences in strength.

Sand the enamel skin off of the bamboo wherever you want the resin to adhere.
Cutting through the skin before you cut the tube will lessen the chance of the skin splitting.
Wrapping the cut in blue painter's tape before cutting will also help.

Bamboo is not perfectly straight. I think you will still have alignment issues if you cut up an old frame and try to make an internally lugged frame.

Use off the shelf (Nova, Henry James, Paragon Machine Works, etc.) metal parts (head tube, bottom bracket, dropouts) and mount them to your jig so they are properly aligned. Fit the bamboo between them.

Miter the bamboo the same as you would using metal tubes, then tweak the fit by sanding the miters so the bamboo lines up as you want.

Contour

Well I'm trying to get away with out a jig but do you think the scratch build is better (a more precise final product)?

Mark Kelly 

I would have thought that the longitudinal fibre alignment of the bamboo tubes would compromise their torsional rigidity .

This is supported by data showing that bamboo has a typical ratio of EI / GJ greater than 8 where isotropic materials with moderate Poisson's ratios (eg metals) give values around 1.3. Since EI / GJ describes the ratio of bending stiffness to twisting stiffness, this says that the bamboo has about 16% of the torsional rigidity of an equally laterally stiff metal tube. Since the bamboo tube will have lateral stiffness less than or equal to that of a metal tube of the same diameter and weight, this gives it at best 1/6th of the torsional rigidity.

It is well known that torsional rigidity of frame tubes is extremely important for handling - you don't want the down tube and top tube twisting enough to pull the head tube out of alignment with the rest of the frame.

Am I missing something or is this another case of something which looks like a good idea but really isn't?

noglider 

Mark Kelly, you obviously know a heck of a lot about materials than most of us do. I relish your question and hope for an answer from somewhere.

Allen

I'm building off of a level table, not unlike Otto's setup here: https://ottobelden.blogspot.com/2009/...struction.html

Allen

Contour, read through this thread too: https://www.bikeforums.net/showthread...on-fiber-build

bamboobikemaker

Contour, if you're creative, you can get everything lined up appropriately with out an expensive jig system. It's not very practical, so it would not be efficient for mass production, but for one offs I'm sure you'll think of something.

Thank you,
phil

Canaboo

I made a bamboo bike recently and the process is remarkably simple. You can align by eye if you're used to doing any work that requires some experience with this. My bike tracks perfectly.
I used bamboo from a flower shop and a garden center and chopped up a few steel frames for the necessary parts.
I didn't bother with heat treating. Tests show that as soon as you heat bamboo to a darker color you significantly weaken it (although it does become stiffer).
You will notice that bamboo poles in a typical selection may be splintered and cracked or perfectly sound. Since the sound bamboo has probably been sitting for several years through a huge range of moisture and heat cycles without cracking you can be more sure it will continue to do so in the future.
Imported bamboo has already been fumigated twice for bugs so it is hardly necessary to do that.
A good finish renders it impervious to moisture and appeal to insects anyway.

For gluing I would recommend going by a proven Epoxy system. I like System 3. Resins. They have an appropriate Epoxy for every application in the process and though it may not matter they are all likely more compatible with each other than using types from several companies.
I wrapped the lugs with a combination of Fiberglass, Carbon cloth and Manila hemp(for the natural look).
You need to cover the metal parts with glass cloth before you wrap with carbon. As far as tow versus cloth, by the time you finish wrapping a lug with tow it IS practically woven.

As far as worrying about torsional stiffness, I wouldn't. If you try to bend or twist a short length of bamboo tubing it is unyielding. If you wrap your lugs well they will increase the stiffness. With the ends of the tubes locked in place and all braced against each other the accumulated strength of all the parts is incredible.
Once you build one you will start replacing all your other bikes with a homemade version. I'm working on my TT bike now.
Interestingly I'm probably riding the only bamboo bike in Toronto right now and people don't even notice it.

Aaron_F

Canaboo, can we get some photos to drool over?

Canaboo

Here's a few. Sorry it's a bit dirty from riding on dirty roads. Not really drool-worthy but a good basher for rough roads. The parts are very low end in case somebody gets the bright idea of hacksawing it to get the parts.

Allen

Very nice!
What resin are you using?
What's your build process, tape, vacuum bagging?
How much clean up did you do on your lugs? They look swank.

More, I must have more.

Seriously, that's a sweet bike.

Canaboo

Thanks. I just tacked this bike together with the same resin I wrapped it with(MAS Epoxy). I had some carbon and glass tape which I used as an initial overlay of all the lugs and then wrapped them twice with the Manila. After the first layer cured I sanded them and then applied one more thin layer of Manila as neatly as I could, sanded them again and smoothed on one more layer of resin.
I used inner tube strips in place of vacuum bagging. That compresses the matrix and squeezes out the excess resin. After it cures the tubing peels off and the surface is very smooth and only needs any ridges of resin flattened.
I did sand the ridges of the nodes down since the bamboo wasn't the greatest in quality. That doesn't weaken it if you just knock off the lip of the node and don't try to completely flatten it. The bike is very stout. I can place my hands on the top tube and bounce my weight onto it with no signs of creaking or bending.

old goat

Hey canaboo. You have inspired me to build a bamboo bike like yours. I located a old centurian road frame that I will be using as a doner fot the BB, HT and dropouts. I'm having some trouble finding a source for the bamboo. I live in MA and can't seem to find any growing beside the road. The online places seem to require a fairly large minimum order.Can anyone point me to a good source of bamboo?

Canaboo

www.bamboofencer.com has bamboo poles. Tonkin is a good choice for smooth nodes and all around strength and resiliency. It's the type used for making fishing rods.
I managed to get some up here and it is incredible stuff.

old goat

Thanks for the info. I ordered the bamboo today.I also ordered all the neccessary metal bits from Nova.I am working on drafting a full size blueprint and building a jig so that I can start assembly when the material shows up. When it comes time to wrap the joints I will asking more questions on this forum because I have not worked with composites before.

dj2wheels

AllenG, I liked the dropouts that Otto designed for his friend, they look very similar to what Calfee uses, at least in terms of the bolt adjustable angle. Been following this thread, kind of lurking, and the question that I have is what kind of drop outs are you guys using on your bamboo frames and how are you attaching them to the stays? It seems that most dropouts that I can readily find on the www are pre-made at a certain angle for the stays and not easily adjustable. I wold love to get my hands on some similar to what Calfee uses, or that Otto guy.