Sunday 17 December 2017

The finished bike

The bike has now done loads of miles in good and bad weather. My first trip over a cattle grid was a bit nerve-wracking. I am really proud of it and I really enjoy riding it - I can't wait for the lighter days of Spring and Summer. The bike is great.

I've learnt loads from doing this and am much more confident and capable at bike mechanics now. The project has been great in that respect alone.

I'd like to point out how helpful the chaps at Bamboo Bicycle Club have been. As you can see, I made a few errors (including one biggie) and they were really helpful. I really didn't feel I was on my own.

I'd definitely recommend it - nothing about the process is hard and even if you do make a mistake, you can correct it. I don't have any great DIY experience and it really wasn't any problem.

Video 5 - the finished bike


Fitting out the bike



Bamboo Bike – fitting out
You might want to keep this old Bamboo Bicycle Club guide for reference. It contains details of the sizing of the tubes etc: http://bamboobicycleclub.org/Downloads/WORKMANSHIP%20GUIDE.pdf

Now my frame was finished, I started the process of fitting it out. I was canibalising a ten-year-old Orbea Enol (ebay £102).

Front derailleur hanging
I used a front derailleur (the bike has two cogs on the front). I bought a 34mm hanger/braze-on for £6 – however it was much too small in diameter for the seat-post. I got round this by sawing half-way round the arms of the hanger and then bent the stumpy arms to make sure they were a snug fit round the circumference of the seat post (although, of course, this only goes about half way round the seatpost as it isn’t now long enough to go all the way round).

 I then drilled three holes in the hanger and roughed up the rear of the metal with the green dremel grinding bit. I then used epoxy glue to glue (and screw) the hanger to the seat post (taking care to position it correctly). I made the holes in the seatpost for the screws by hand with a bradawl. I practised this by doing a dry run of the hole-making on an off-cut of bamboo. It was surprisingly strong. Remember to remove the waxy bamboo finish from the area of the braze-on before sticking it on. Take take care to ensure the derailleur positioning will be just right.

Steering
The steering tube in the kit is a 1 1/8 inch standard threadless tube. You will need to fit a headset on this – I would recommend buying the unit and taking it to the Local Bike Shop to fit. Perhaps you could do this yourself with some bits of wood and a hammer but I read some scare stories about getting this wrong. I thought “why risk your frame for a £15 job?”.

You need a 1 1/8 thread-less external cups Lo-profile headset. I went for a M Part In-Line Lo-Profile Threadless Headset.

Note: If getting the LBS to fit this, also take along your fork- they can also fit the bearing run on the fork at the same time – saving you an awkward job. Foolishly, I didn't do this and found I needed to replace the bearing race on the Orbea fork with the one that came with the headset. This was new to me – I carefully used a chisel to start to prise up the race from the fork. Take care not to dig into the metal of the fork with the chisel - but once the race starts to rise, it can easily be worked up with an old screwdriver. This was quite an easy task. The harder part was putting the new race on the fork.The bearing race is pretty snug at the base of the fork and it is easy to damage it (hence the LBS have proper tools). I managed to fit it by using the old Orbea heaset – I put the fork into the Orbea steering tube and hammered the fork in (using a piece of wood to receive the hammer blows). Slowly (I mean slowly), the race worked its way onto the fork.

Also, before taking the frame and fork to the LBS, make sure the hemp around the top of the tube is flat and that no hemp is raised above the top of the metal tube (the headset gets pushed into the top of the tube).

At this point I realised that I needed some Steering Spacers (you might also need some – they are cheap and you might want to get some in advance). Remember it’s standard 1 1/8 inch fork. I also needed a new steering stem (the one on the Orbea was at the wrong angle). The Bamboo Bike Club seem to suggest a 90mm stem long with a 7 degree rise, so I went for that. If you also need to change the stem, you need to make sure the stem order fits the handlebar – I had to use some maths here to find the right size. I wrapped some tape round the handlebar and then unwrapped it to work out the circumference of the tube. I then divided that figure by 3.142 (pi) to get the diameter of the handlebar. Handlebar sizes all seem to be given in diameters rather than the circumference.

Fitting the rear brake
My next problem was the rear brake. I positioned the brake (using the wheel and the old frame to work out exactly how high the bolt hole needed to be above the top of the tyre. I had a few problems. One problem was that the bolt on the brake was much shorter than the thickness of the bamboo. Perhaps there is a way to change the bolt length on the brake, or perhaps I could have used an old front-brake (on older bikes they have longer bolts). Anyway, I have solved the problem for now by drilling the hole exactly the same diameter as the bolt. I then screwed in the brake, using the thread of the bolt to carve a thread into the hemp and bamboo. This seems to have worked, although I don’t have a nut on the brake bolt at the moment. The direction of travel of the wheel means that the brake is always pushing against the frame, so it’s not going to suddenly spring out. I think I am OK for now (I might just glue the bolt in place if I get any issues).

The other issue I had was that the hole I drilled for the brake bolt wasn’t exactly straight. Consequently, the left-side brake block was tucked inside the frame – it wouldn’t spring back. I solved this problem by buying some shorter old-style brake blocks and hack-sawing a few millimetres from the tip of the block. This works perfectly and my rear brake functions very well.

Seat Post
I had problems with the seat post slipping. This turned out to be due to the clamp on the canabalised bike being the wrong size. According to the “finishing guide” you need a 27.2mm seat post and the seat clamp needs to be 28.6mm. The seat post on my Orbea was 27.2 mm, but the clamp was too big. I ordered a 28.6mm clamp and some Weldtite tft carbon fibre gripper paste from ebay. That’s all working fine now.



Video 4 - finishing the frame


Learning points - part 2



Applying the hemp
Applying the hemp and epoxy is very messy – I recommend you use small batches of glue. I also recommend wearing clothes that can go straight into bin when you’ve finished (I didn’t do that and now have very stiff sleeves on my overalls)!

Check the underside of the wrapping as you go – I left two big gaps on the underside when wrapping the headtube joint. I had to add more epoxy via a second gluing 24 hrs after the initial gluing. I also added more hemp & epoxy to the bottom bracket area which I felt looked less strong than other areas. When doing a second gluing, take care not to get epoxy in the inside of the metalwork (especially the bottom bracket). I used sponges tightly wedged into the metal ensure they stayed clean.

To wash the epoxy from your hands I found vinegar very useful. You could use white spirit and then rub with moist wipes (of the type you find in packs of kitchen/surface wipes). If you get any epoxy anywhere it shouldn’t be, you can get it off with vinegar if it hasn’t fully cured.

Don’t make the mistake I made – I had to go out after the hemping process and ended up leaving the wrapped epoxy for about 7 hours before I came to take the tape off. It was almost fully set by the time I came to unpick it. As a guide, if you are doing it outside, I suggest that at around 20 degrees leave it for about 3 to 3 ½ hours.

Make sure you use good quality tape and wrap the electrical tape the right way round (i.e. with the non-sticky side against the hemp) – I messed up one of the chainstays, and owing to the fact that it had set, it was extremely difficult to pick off the tape. Avoid using very thin tape - if it breaks and struggles to come off the roll easily, it might be to thin and could be difficult to get off the lugs.

When you come to clean up the fully dried hemp lugs, gently prising the reluctant tap off with a 1/4 inch thin chisel worked really well (again from ebay). Also, this is where a dremel and sanding drum might come in handy - if the epoxy has fully hardened, you can just sand off any rogue electrical tape - easy.

Sanding
I decided to smooth and paint the hemp lugs. I used a dremel and also sanded by hand. Don’t file down the hemp too much as that would affect the strength. I didn’t file much of epoxy at all (only the odd spiky lumps really). I then applied Autocare easy-sand car body filler (£6 from ebay or Wilco). I then sanded the filler and applied primer, applying two coats of primer (using a poundland brush-set). I probably should have done more sanding and filling but got a bit bored and wanted to get it finished. It is probably best to have more patience than I displayed.

Painting
I then painted the lugs black (a poundland primer and two coats of black car paint applied with a brush). The paint I used was cheap auto paint from Poundland (although I used ‘spray paint’ I sprayed batches into a tub so I could apply it as a liquid with a brush. This was done only because it was the cheap option. The finish was perfectly adequate (for me).

Decals/Stickers
I made my own decals using powerpoint and some print-yourself adhesive acetate sheets (from ebay). Standard printer ink isn’t waterproof (laser printing is waterproof) so I stuck a clean piece of the adhesive acetate on top of the printed sticker sheet. I’m hoping that the sandwiched sheets are waterproof.

Lacquer
I finished the bike by applying lacquer finish by spray to the whole bike frame (before attaching the wheels, forks etc).

Frame weight
The cleaned up frame weighed about 2.7kg and felt reassuringly strong. 

Video 3 - hemping the joints


My big mistake

My biggest mistake became apparent only after I had hemped all the joints and put the rear wheel on.

I clearly hadn't got the rear drop-out jig straight. You can see this in the Video 2 where I had stupidly tried to get it straight by wedging a stirrer under one corner of the jig. If you get the drill whole fairly straight and screw the jig tight to the board it should be self-straightening.  I made a real rooky mistake here.

It wasn't until it came to put the bike together that I realised the the rear wheel rubbed badly on the frame. It was completely wonky. The problem was on the non-drive-side drop-out. Thinking about it, with this kit, any rear wheel alignment problems are probably going to be on the non-drive-side (the design of the jig means that he drive-side is pretty-much always going to be correct as it is very closer to the mdf board). The non-drive-side is quite some distance from the board so there is more scope for something to get our of alignment on that side.

So, I got out my Dremel, (and some sanding drums) a ¼ inch chisel and my junior hacksaw and took all the epoxy off the drop-out. It took about 2 hours of work. When I re-positioned the drop-outs, I used the rear wheel to get the exact position. I bought some more epoxy tacking glue from ebay. I checked the positioning many times before I re-hemped the lugs. I would definitely recommend carefully using an actual wheel to check the rear drop-outs before and after tacking and before hemping the lugs.