I learnt loads as I went along and made quite a few mistakes. Fortunately, all were correctable:
Setting up the jig
I think it is important to drill your holes for the jig as straight as possible.
One good tip is to get an old CD and place the drill bit in the middle –
the reflection of the bit makes it easy to tell if the drill bit is going in
straight.
Bamboo is oval
I didn’t realised it at first, but bamboo actually has an
oval cross-section. You should factor in this fact when working out where to
mitre the joints.
The piece to use for the Downtube
Use your thickest piece of bamboo for the Down Tube
(this tube undergoes more stress than any other section).
Seatpost bamboo
Identify which piece you are going to use for the seatpost – it needs to
be the one that that is almost exactly the same size as the seatpost shim.
Although the instructions say you need to file down the inside of the bamboo to
make the shim fit, I found my bamboo piece was slightly larger than the shim. In this
scenario you should use lolly sticks (or better-still, wooden drink stirrers)
to pad out the gap when you add the epoxy glue. Don’t ram the shim in too
tightly or you could split the bamboo. Remember to leave about 20 –
22mm of shim poking out the seatpost.
Mitring
The downtube is the hardest one to do. The two joints (with the Bottom
Bracket and the Head Tube) need to be mitred at right-angles to each other.
Keep checking as you go. Remember that the Downtube will ultimately need to be
fixed in the middle of the bottom bracket shim.
I found it quite hard going to mitre by hand. You get there in the end
but I found it was easier to get going if I made diagonal saw cuts about 8mm in from
the end (remember to use masking tape when making any cut and DEFINITELY don’t
go deeper than 1cm or you could-well mess up the piece entirely).
Sandpaper
I needed more sandpaper than the supplied piece. It might be a good idea
to get some more aluminium oxide sandpaper (grade 60 or 80) – it is best to use good
quality paper.
Epoxy glue
I used up the supplied sachets quite quickly (mainly because I messed up
the rear stays). You might want to buy extra from ebay (£2 for the four tubes).
Scraping the waxy surface
I found the prospect of scraping away the waxy surface a bit daunting.
Practice doing it on a scrap piece of bamboo – it’s actually really easy
and there is nothing to worry about.
Once the bamboo is mitred
Be careful with bamboo once mitred as it feels a bit delicate.
Perhaps put some cloth on the board under the joints so that if one slips off
before it has been tacked that there is no risk of it falling hard on the mdf board and splitting?
Rear Triangle
When doing the rear triangle, I personally think it is best to mitre the
joint with the seatpost before you cut it to the exact length.
I had problems getting the mitre angle of the join correct (particularly with the
stay that joins to the underside of the seatpost). It might be that I've just got some
‘spacial awareness’ blind-spot.
Take care to follow the lines of the drawing plan when looking at where
to join the bamboo together. I messed up the rear seat stay
join and tacked it and joined it too low – a really dumb mistake and I had to
re-do with new bamboo.
Filling gaps
I had some rather bit gaps between the rear stays and the
drop-outs. I struggled with the recommended approach to filling any large
gaps in joints. The kit recommends mixing glue and bamboo dust.
I resorted to using a few bits of polymorph for a couple of the holes (however, should point out that I like polymorph and use it for loads of things).
I filled some of the very small gaps with gorilla glue (inc the gap
where the shim poked out of the seatpost – the glue is quite runny
and takes a few hours to dry but it does bubble up to fill the small gaps.
Rear bridge
I used a dremel to get the rear bridge mitring right. They are only £25 and came with lots of tools - really recommend getting one. I got one for this project and used it for
loads of things since then.
I wasn’t good at the seat stay and bridge mitreing (I did the larger
joints with no trouble at all). TBH I don’t know why I struggled as it should
have been easy.
I made the rear bridge solid by inserting a shaped piece of wood into
the cavity before I fixed it onto the bike with glue. I’m pleased I did
this as I think it has made the rear brake much stronger and helped when it came to adding the brakes.
Cutting the hemp cloth
When preparing to wrap with cloth and epoxy, make sure you cut the hemp in
the correct direction. I messed this up and cut loads of it so that it was
weak. You want to get the fabric of the weave running along the length of the
strips. If in doubt cut two very thin strips (c 5mm) from the different sides
of the cloth – then pull them hard to test. You will soon see which is the weak
direction – do it the wrong way and it just falls to pieces much too easily.
You will need lots of pots for the glue (probably need 5 or 6). You can
cut the bottom off 2l plastic drinks bottles if you run out (although I used
large yogurt pots).
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