The Idea

Posted: 15th May 2010 by Nigel in Bamboo Bike, Getting Organized

I am passionate advocate of environmental responsibility, and have a keen interest in alternative transportation. When I received my letter of acceptance to the Said Business School at the University of Oxford, I started thinking about what I would do for transportation. Oxford is definitely a cycling town, so a bike is the natural choice. I wanted to bring one of my nice bikes, either my Specialized Roubaix or my fixed gear, but bike theft is a big issue at Oxford, and both of those bikes are too flashy and expensive.

So in the end, I came to the natural conclusion that I should build myself a bamboo bike. Which should be as simple as

1. grab some bamboo

2. pull out my tools

3. make a bike

This blog will detail the trials and tribulations that are sure to ensue as I take on this ambitious project. I hope you find it entertaining or educational, ideally both.

[photo credits: annieo76, bre pettis, and sara.t.g on Flickr]

Standing on Shoulders

Posted: 18th May 2010 by Nigel in Bamboo Bike, Getting Organized

The following are the sources which inspired me to start this project.

I first leaned about bamboo bikes on the CBC radio show Spark

Episode 107 from March 28 & 30, 2010 had a segment on the Bamboo Bike Studio in Brooklyn, which is a really cool social enterprise. You pay just over $900 for a weekend course where you build a bamboo bike and then ride away on it. They also put some of the money from the course towards setting up bamboo bike building capacity in developing nations.

My searching brought me to CalfeeDesign which is a high end shop which builds beautiful custom bamboo bikes at prices which are largely unaffordable. They also have a lower cost counterpart, Bamboosero, which are frames built by entrepreneurs in developing countries.

Finally I came across several tutorials on instructables.com. The one I will follow will be this one, and I also found this one and this one to be valuable.

Goals

Posted: 21st May 2010 by Nigel in Bamboo Bike, Getting Organized

Once I did more research into my different options, it has become evident that I need to have very clear goals about what I am trying to achieve. This will allow me to make clear choices regarding frame design and components, among other things. I have come up with the following priorities, in no particular order.

  • Sustainable – It is very important to me that I keep sustainability in mind during the decision making process. For me, this means using used components, locally sourced materials when possible, and minimizing waste.
  • Responsive yet compliant – As an avid cyclist, I know I won’t be happy with a frame with too relaxed of geometry. However, The purpose of this bike is to navigate city streets on trips generally less than 5km, so stiff frame with full track geometry is overkill. My goal will be to strike a balance between compliance and performance.
  • Unattractive to thieves – I feel that by its very nature, a bamboo bike won’t be a hot ticket item for thieves since it will be a real challenge to sell, plus I will build it up with lower end components to make sure that it won’t be worth taking a wood saw to the frame to get at the bits and pieces.
  • Simple and overbuilt – Since I won’t have access to my tools at Oxford, I intend to build up the bike to be as simple as possible: fixed gear with a flip-flop hub, front brake, flat bars, larger tires, and an overbuilt frame.

Donor Bike

Posted: 23rd May 2010 by Nigel in Bamboo Bike, Gathering Parts

I picked up my donor bike this weekend. She’s a beauty I grabbed off of craigslist. It has changed hands twice already, but has only been on the road a couple times since it was built in 2009 so it’s in great shape. It’s a Kona Paddy Wagon, which is an entry level fixed gear/single speed. My major complaint is that it doesn’t have a sealed bottom bracket, but it will do the job. I paid $400 (as compared to a new price of over $800), and I figure I can sell the components I don’t use for more than $200.

I had to drive out to Fort Langley to pick up the bike, so I figured I would take the opportunity to do a ride over the new Golden Ears Bridge. Plus it was a gorgeous day!

Bamboo Harvest

Posted: 9th June 2010 by Nigel in Bamboo Bike, Working with Bamboo

Today was an exciting day; I harvested the bamboo to use for my bike. I had been searching around for some appropriate timbre bamboo, and I really didn’t find anything. All commercially available bamboo was from Asia, even though it grows like a week here. Fortunately I found someone on craigslist who was “thinning out his grove” and was selling some bamboo. No pictures, no prices, lots of capital letters.

It took a few emails before he responded, and then I went over there to see what he had. The ad said “grove” so I was expecting a large forest type area on a large piece of property around the back of the house with bamboo. What I found was quite different. It was a tiny property in a fairly dense residential neighbourhood about half way between my house and downtown Vancouver. The whole house was hidden behind hundreds of large bamboo shoots, which had expanded to both sides of the sidewalk. The proprietor, Jack, was a quirky fellow who answered the door with pot smoke billowing out around him. Long (did I mention long?) story short, I cut down a piece of my choosing for $15.

I pulled out my trusty calipers to ensure I got a piece which was the perfect diameter. It was also important for it to be straight, with very few branches for the first 30+ feet so that I could make the whole bike from a single shoot.Then I cut it down with a hacksaw and very carefully drove home. Fortunately I only live a few kilometres away.

As a side note, this is what a new bamboo shoot looks like.

Heat Treating Bamboo

Posted: 11th June 2010 by Nigel in Bamboo Bike, Working with Bamboo

Heat treating is an important process for preparing bamboo. Essentially it removes a lot of the moisture, making the poles lighter, and most importantly it cooks the sugars in the shoots. Bamboo is a species of grass, much like sugar cane, and is full of sugars. When these sugars are cooked, they turn from being a thin liquid to becoming hard, much like the process of turning maple sap into maple candy. The hardening of the sugars binds the fibres in the shoot, creating a very strong tube. If you think this sounds familiar, it is because it is. The same process is used with pre-impregnated carbon fibre, basically making bamboo nature’s composite.

The process I used was recommended by a few different people who have provided online tutorials on bamboo. See this tutorial for an overview and this forum for a wealth of knowledge on all things bamboo.

EDIT: for a video of this process, check out this post.

  1. Use fresh bamboo, as green as possible. Cut it to lengths that are a little longer than you need right before you heat treat, being careful not to split the bamboo.
  2. If the section is long enough that there are more than two nodes, drill them out. Otherwise the pressure in the sealed centre section will make the piece explode.
  3. Use a regular pencil blowtorch, and start with a quick once over. The goal is to draw out the wax and oils and wipe them off with a lint-free cloth. Heat the piece section by section, hot enough that there is visible bubbling on the surface, but no discolouration. Then wipe off the oil and wax before it is reabsorbed.
  4. With a slow, steady typewriter-style motion, heat the bamboo to a yellowish colour. The torch should be about 5-10cm from the bamboo. If you burn a few sections, don’t worry. Keep moving, and you will come back to darken the whole thing again in the next step.
  5. Allow the section to cool, and then go over it again. This time you will bring it to your desired colour. I went with a mid to dark brown. You can go anywhere from very light brown to almost black. If you go too dark, or you burn a section, you can sand it later and it will expose lighter wood underneath.
  6. Seal the wood with something. I used pure beeswax, but you could use any kind of wood sealer. To seal with beeswax, rub the bamboo down when it is still hot, then wipe off the excess with a lint-free cloth.

I will post a video in a couple days.

Heat Treating Bamboo (video)

Posted: 13th June 2010 by Nigel in Bamboo Bike, Working with Bamboo

Here is a video I made on heat treating bamboo. For more information about why it is important to heat treat bamboo, and for step-by-step instructions with pictures, see this post.

Donor Bike Number 2

Posted: 15th June 2010 by Nigel in Bamboo Bike, Gathering Parts

The easy thing would have been to cut up the track frame from my donor bike. It was about my size, so I could replace the steel sections, one at a time, making only small adjustments to the frame size. That, however, would go against my goal of minimizing waste. Instead, I sold that perfectly good frame so it can be used for years to come, and I am using a circa 1980 steel frame Norco road bike which has clearly reached the end of its useful life. The brakes were shot, as was the derailer and tires. The wheels needed truing, and the bottom bracket had a very significant amount of play in it. The bike could have been restored, but it was at best an entry level bike 30 years ago, so it was not really worth the cost to restore. As a side note, I just finished restoring my dad’s 70-something Guerciotti to new condition, and it cost well over $1000.

The first step was to assess what I could use which parts could be useful on this bike. My original plan was to just use the bottom bracket shell, head tube and drop outs, and I was going to get a carbon fork. However, on closer inspection, the rust on the fork is surface level only, so I will brush the paint and rust off and wrap it in the leftover carbon from my frame layup. I can also use the stem, and I will keep the chain stays, wrapping them in carbon for extra strength (and look). I also found that the headset was surprisingly usable. None of the bearings had cracked, and there was only light grooving in the bearing seat. It seemed as if it hadn’t had the bearings cleaned and greased in over a decade, but one of the great things about these old road bikes is that everything is designed to be rebuild able. Sealed cartridges are nice, but when they need to be rebuilt, you often either have to ship them back to the supplier or throw them out.

Next I had to take all the parts off, and hack off the frame parts that I will keep, and then grind off all the paint to prep them for the layup. I ran into a snag when I tried to remove the cranks. I have the right tools to remove the bottom bracket, but I don’t have a square taper crank puller. I dropped it off at my LBS (Jubilee Cycles), but being June, they were too busy to pop them off on the spot. I could only get as far as prepping the head tube. To be continued…

Mitring the Joints

Posted: 18th June 2010 by Nigel in Bamboo Bike, The Build, Working with Bamboo

To ensure a strong frame, you need to mitre the joints well, and it is a fairly challenging process. When you join two square objects, it is pretty straight forward. You just cut a straight line and bam! you are good to go. Joining two tubes is more complicated, since you have to cut a curve into one so that they fit. When those tubes are different sizes, not perfectly round, and several join together at different angles, things get a little tricky. For this stage in the build I relied on my good friend Nicholas McFarlane and his dad John, who have a basement full of wood tools and a great deal of expertise.

After a little brain storming, we decided to use a drill press. By using a hole cutting bit, we were able to drill a hole the size of the tube to be joined to and at the correct angle. Since the angles were all fairly rough, and I was cutting everything over length to allow for fine tuning later, the process only took an hour or two once I got going (after some excellent training from the McFarlane’s of course). Essentially the steps are as follows:

1. measure the size of the tube to be joined to and select the right bit size

2. measure the angle and set up that angle on the drill press

3. drill out the desired hole size at the desired angle

Next I had to measure it all up again, and file by hand to create a perfect fit. This took a long long time. Seriously, it took a while. But in the end, I think did a pretty good job.

Building the Frame (pictures only)

Posted: 18th June 2010 by Nigel in Bamboo Bike, The Build

Last night Jame Kay and I put together the frame and did the wet layup. I will do a complete post later, but for now you can look at the pretty pictures. Read the rest of this entry »

Tacking the Frame

Posted: 22nd June 2010 by Nigel in Bamboo Bike, The Build

Once all the sections of bamboo have been heat treated, cut to length and mitred, and once the metal sections have been prepped, then you are ready to prep the frame for a wet layup. A wet layup takes several hours, and requires the frame to be held at different angles and loads to be applied as the carbon is laid up. To ensure that you end up with a nice straight frame, you need to create solid bonds at each joint.

First we had to figure out how to get the frame to be straight in all the appropriate dimensions. If we end up building more in the future, then we will build a jig, however I think for a one-off a jig is a bit overkill. That being said, a using a jig is really the ideal way to do this step, so the following is not so much a set of instructions as it is an explanation of how I tacked my frame together. Please take that into consideration if you make your own bamboo bike.

I had decided to use the steel chain stays from the donor bike partly because of the tension, compression and torque loads that are applied on them when riding, and also to help with getting the whole bike to be straight and true. It was a trade-off because I had to compromise with a longer than desirable wheelbase, and I would have liked to build the whole bike out of bamboo (I even treated, cut and mitred bamboo chain stays), but in the end I think I made the right choice.

We (Jame Kay, who was invaluable in this phase of the build, and I) started by tacking the seat tube the bottom bracket shell, which was conveniently already attached to the chain stays. To get it to set straight, we put on the rear wheel, put a spacer between the wheels and the seat tube, and sighted from behind the wheel to ensure it was straight up. Once we were satisfied this would work, we popped the seat tube off, slapped some 5-minute epoxy on the joint, and then taped it all in place. Read the rest of this entry »

The Carbon Fiber Layup

Posted: 27th June 2010 by Nigel in Bamboo Bike, The Build

Once the frame was tacked with 5-minute epoxy, we were ready for the layup. Here is what you will need for a wet layup:

1. Carbon fiber tow, basically 5mm wide unwoven carbon fiber (find it on eBay)

2. Epoxy resin and hardener suitable for use with carbon fiber

3. 100 grit sand paper

4. Cheap paint brushes (get at least 5, you will throw one out after every batch of epoxy sets)

5. Lots of pairs of gloves

6. Plastic masking material

7. Ideally a gram scale, but disposable volume measures will due (such as shot glasses)

I would have taken more pictures, but with wet epoxy everywhere it was a real challenge.

Start by mixing up a batch of epoxy. Be sure to follow the directions because mixing ratios vary. Also, you should be well aware of the working time, as it can range from a couple minutes to a few hours.

Next you should paint it onto the part. The surfaces should all be rough, so sand first if necessary.

Then wrap the wet surface with carbon fiber tow until it starts to look dry. Wrap a couple more layers and then paint on some more epoxy. It is easiest if you spool off 20 or 30 meters at a time onto a smaller spool so you can get around tricky corners. They key is to ensure that you wrap in all the directions where load is expected to be applied. Remember, carbon fiber is only strong in the direction of the tow, so if you don’t wrap in a direction where load is applied, the joint will fail.

The wet layup took about 4 hours, and the working time for the epoxy we used was just over an hour, so we made three pots. After 48 hours of curing time, the joints were strong!

Finishing Touches

Posted: 7th July 2010 by Nigel in Miscellany

After the epoxy had set, I was ready for the finishing touches. I sanded down all the joints with 80 grit sandpaper to smooth them out, then applied a second coat of epoxy for a nice finish. Once that had set, I put on the bottom bracket, cranks, pedals, wheels and chain, and I was all done!

Here are a few close pictures of the joints

Since I didn’t have my choice of donor bike, the head tube is too short for me. To overcome this, I got a $20 fork with a long steerer tube, and made a nice looking bamboo spacer. Now the bars are the right height. Unfortunately, I think I grabbed a fork for a 27inch wheel, which is designed for a front wheel that is 14mm smaller in diameter then the 700c wheels I am using. I was able to file it down to fit, but I can’t fit it with brakes. I will replace it with a 80s carbon fork. They occasionally come up pretty cheap on eBay, they look pretty cool, and they are light weight. I can’t use a standard fork, because the head tube is for a 1 inch threaded fork rather than the standard 1 1/4 inch threadless.

The bike weighs in at 21.5lbs. Thats fairly light, but heavier than I was aiming for. The fork I have on right now is very heavy, so I should be able to shave 1.5 to 2 lbs with a carbon fork, bringing it into line with what I was going for. It has now joined my stable.

Epoxy Coating, New Seat Post Mount

Posted: 6th August 2010 by Nigel in Miscellany

In order to waterproof and otherwise protect the bamboo, I finally decided that I would have to put on a coating. I really loved the look of the bare bamboo, but after I got my first scratch, I decided for the good of the bike I would have to put on a protective coating. Since I had lots of epoxy, I went with an epoxy coating. I sanded the all of the bamboo surfaces with 80 grit wood sand paper, and wiped the dust off with a damp rag. Then I mixed up a batch of high optical clarity epoxy, and diluted it 50/50 with acetone. The acetone thins the epoxy out, and helps it to get absorbed into the wood. It took more than 24 hours to set, and I am really happy with the result. It created a much deeper, more saturated luster, with a little gloss to it.

While I was at it, I also had to repair the seat post mount. The original method I used to mount the seat post turned out to be highly ineffective. Basically after about an hour of riding, the bond between the piece of steel and the carbon broke.

Old seat post mount: I rebuilt it by cutting off the top 2cm, wrapping a seat post in a non-stick tape, and laying up some carbon. Once it cured, I cut the carbon with a hack saw to create space for the clamp to squeeze the tube. Hopefully this will work.

New Wheels

Posted: 23rd August 2010 by Nigel in Miscellany

After riding WhamBam a few times, it has quickly become apparent that there is not enough ground clearance under the pedals when cornering. This was due to the fact that we didn’t use a jig when assembling the frame. I made plenty of calculations for the appropriate geometry, but in the end, we more or less had to eyeball the angle between the forward triangle and the chain stays. The clearance is not too bad, except for the fact that I was intending the bike to be a fixed gear, which doesn’t allow you to coast with the outside pedal down during hard cornering. This left me with two options, either go with shorter cranks, or scrap the fixed-gear idea. I went with the later option.

My first thought was to swap it over to a single-speed, especially since the wheelset I was using already had a flip-flop hub and a freewheel on one side. However, this would require building a brake mount into the seat stays, which would apply a force right in the middle of the seat stays, perpendicular to the load they were intended for. The would probably be strong enough, but without load testing, I wouldn’t really be comfortable with that setup. Imagine the catastrophic failure potential: blowing out the seat stays under heavy braking… not good.

So then I settled on a coaster brake, which would require a new rear wheel. This is the result:

New Camera

Posted: 23rd September 2010 by Nigel in Miscellany

I picked up a digital SLR camera today for only £175 ($280). Its an Olympus E-510, which was a great mid-level prosumer when it came out in 2007, and still has all the features I need. It was only used twice, and is only a year old.

Why did someone buy a $1000 camera only to use it twice? It makes me wonder how much better the world would be if the consumerism in our lives was based around leasing, renting or time-sharing nice things. It would encourage manufacturers to build our things with longevity in mind, and as soon as you realize you don’t use that guitar or table saw as much as you thought you would, then you can just return it and save on your monthly “stuff” bill.

Anyhow, enough rambling, here is a shot of whambam outside a pub in Oxford. It is processed in pseudo-HDR.

Picture of the day

Posted: 6th October 2010 by Nigel in Miscellany