Posts Tagged ‘Bamboo bike’

The Yellow Bike

Posted: December 15, 2018 in Cycling
Tags: ,

A long time ago I visited a workshop in the depths of London to spend two days playing with bamboo and sharp tools to produce a bike frame. At the end of the weekend I had something that looked like a bike frame, it just needed a little bit of finishing. I took it home, put in in the shed with the intention of doing that finishing and promptly couldn’t find the time to do the finishing as life got in the way.

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Many months and a relocation to another country later the unfinished frame emerged from a packing crate and got put into a corner for a little while. Once the dust had settled, I found that I had the time to actually get the thing finished.

The first problem was working out what finishing needed to be done. It had been a long time since I’d been told and I’d forgotten what to do. I little search on the internet and a few e-mails I had the answer: Apply car body filler over the glue-soaked hessian and them sand it down to smooth off the ragged edges. Once that was done the joints needed to be pained in a suitable colour and then finally the whole lot should be covered in a couple of coats of varnish. Once that was done the frame could be equipped. It would then be ready for the road. It all seemed very straight forward.

Back in my youth I had attempted to smooth out the bumps and dents that I had put into a very old car whilst learning to drive. I hadn’t really done a very good job as the car had gone for scrap soon after. The only knowledge I’d gained from this exercise was not to put the filler on too thickly. I completely ignored this vital piece of experience and put the filler on far too thickly. This was mainly because the filled hardened far quicker that I had expected. This left a very unsatisfactory finish that I thought would be easy to sand down.

I’d borrowed an electric sander as I felt sanding the filler by hand would take more time than I had patience for. I seemed to spend weeks and week going through a sanding followed by filling cycle. Each time I sanded the filler it would result a mainly smooth but with odd ridges finish. I’d then attempt to fill the ridges on and end up putting too much filler on. I started to get the feeling that it was an almost an impossible task to get the finish that I wanted. After several weeks of sanding, chocking on the dust, applying filler, covering myself in filler and cleaning up the mess that I’d made. I got to the point where the result was “good enough”. In reality I lacked the skill to make it any better.

Next was the painting and this presented a whole set of new problems. The first was which paint to use. I had no desire to use car spray paints, which would have been the obvious choice, as I had no desire to fill my lungs with paint after already filling them with filler dust. Then there was the colour. There are so many colours to choose from. I solved the which paint problem by chatting to a man in the paint store. He recommended using paint for rusty metal work as it didn’t require a primer. The colour took a lot longer to settle on.

I put the paint on with a brush and applied as many coats as I could. I wanted the paint work to last and I had no desire to paint the frame again. It was starting to look reasonable. Finally, I covered the entire frame in a couple of coats of varnish. I now had a finished frame. All that I needed to do now was put the components on.

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I spent a long time going through catalogues and websites to try and understand what I needed to buy to complete the bike and came to two conclusions. The first was that it seemed to be extraordinarily expensive to buy each individual component and secondly that I didn’t really have a clue about what I was doing. I needed help.

I visited a few bike shops to ask for advice. The conversation usually started with them sucking air through their teeth before launching into the compilation of some of the most expensive components around. Eventually, I found a shop where the man behind the counter seemed genuinely interested. Instead of going into the list compilation stage his first question was: can I see it. I felt that this was progress.

A few days later I brought my pride and joy into the shop for his appraisal. The news wasn’t good. The distance between the dropouts at the back was “non-standard”. This may have been caused by the back of the frame being slightly twisted. In his opinion, in its current state, it would wear tyres excessively and even worse, potentially break axles as the back axle would not be parallel with the road. He felt that the metal dropouts could be modified to fix the situation but there were no guarantees. He suggested that I leave it with him so that he could see if he could make some adjustments. I left the shop feeling a little down.

I went back a few weeks later to get the verdict. It wasn’t good. In his words “You might as well chop it up for firewood”.

And so ended my bamboo bike dream.

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A Bike is Born

Posted: February 15, 2017 in Cycling
Tags: , , ,

I built a bike frame this weekend, I build it using bamboo and hemp with some epoxy resin and a few metal bits. Here are a few pictures of the stages of construction

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It all started with a jig that holds the metal head tube and the bottom bracket

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We then selected just the right bits of bamboo

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Measured them up against the jig to ensure they were just right. I’d selected a few spares as well, just in case I was visited by the catastrophe fairy

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Then the bamboo had to be cut to fit round the metal bits using a viscous cutting tool and an angle measuring thing (it has a name, I don’t know it)

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The masking tape was there to keep splinters to a minimum, splinters are painful.

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The hole is then cut at the correct angle to fit the tube. This is repeated for all the tubes…

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They can then be put into place on the jig to for the first triangle. A blob of epoxy holds the tubs in place but the tape holds them in place until the epoxy is dry. The cup of tea in the corner is a vital lubricant for the novice bike builder.

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The dropouts are then fixed into position on the jig…

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and slots cut into the chain stays and seat stays so that they fit into the dropouts.

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The chain stays are then fitted into place and fixed using epoxy

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As are the seat stays.

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It now looks like a frame but it doesn’t look like it will stay together in a strong wind.

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The frame is held together with hemp strips that are soaked in epoxy resin and then wrapped around the tubes

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Like this.

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Once the joint is formed it is wrapped in electrical tape whilst the epoxy sets

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Initially the epoxy gets warm as the reaction hardens it, then it cools. Once it is cool the electrical tape can be removed

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And there we have it, one bike frame born from a pile of bamboo, some hemp and a few metal bits. It needs to be finished and lacquered to become a proper frame and then equipped to become a real bike but that will have to wait a while.

This was all done on a weekend course with the Bamboo Bicycle Club