The itch

Totally jonesing to build a new bike. I just got a new tool post for my mini lathe, and I could not be happier with the results from that investment. It cuts, it faces it knurls, and all with much more rigidity and precision than the little runty thing that I've been using thus far. Fabulous.

I've got about 3 bikes in mind for the coming months, and I constantly wish for more time to work on them.

Bike one: potential custom frame for a bike club friend of mine. Could be cool. He's deciding on whether or not to make it a track bike or a road bike. I'm kind of hoping that he'll want a track bike, since I haven't had a chance to make one of those yet.

Bike Two: cyclocross frame for myself. I have long thought that Bamboo would be ideal for CX since it soaks up so much vibration. My hangup here is that I would want to run a tapered headtube, and I don't have a source for that yet. None of the aftermarket fork manufacturers currently offer a tapered steertube CX fork. I was also thinking that I could go with something with an aluminum steerer to avoid excess brake chatter and frame flex, but I don't know if I want to bother if I can't do the type of job that I want.

Bike 3: actually two bikes for a guy that I met through the bike shop. He has in mind some sort of upright dirt trail bikes, a matching (kind of) set for him and his wife. This project will develop a bit over the next few months I think, but I'm looking forward to trying to build two of the same thing.

Some Advice on Bamboo

Selecting bamboo: For most of the stuff that I've found around here, the best pieces are the sections closest to the ground to about 6 feet up. These have the thickest walls. Go for wall thickness at least 5 mm for main tubes, 3.5 to 4 for things like seatstays etc. The major issue with bamboo is not so much the actual break strength, but the flexibility. It's not so stiff, which is why I've done most of my bikes with carbon bits. The other issue for you will likely be finding exterior diameters that are appropriately sized. The outside fibers of the culm are the strongest, and so it's not a great idea to whittle those away too much to fit it inside of a lug. The other thing, is that there aren't any dead straight pieces of bamboo in the world, they all have some deviation to them, making it a bit more interesting to find the right size/shape. This works fine with my construction methods, but I am guessing that you're planning on taking a stab at a bike somewhat similar to the Panda Cycles model.

As far as the treatment goes, I followed a process somewhat like that in the bamboo forums website: heat treat with a blowtorch when green, then air dry for several months, or torch first and then 2 hours in the oven at about 200 degrees. Some pieces will crack for sure with this process, but that's just part of the game, better crack in the oven than on your bike.

When torching, you'll see the color of the outside change, it'll look like it's fading in sudden increments. Oil will also rise to the surface at this point, so you should wipe this off with a rag. Once cooled and dried, i take a razor blade and scrape off the outside of the bamboo, mostly for aesthetics, but also because epoxy doesn't stick to the waxy skin.

For bonding bamboo to other stuff, make sure to sand the joint and wipe down with some acetone or similar to remove excess oil. I use the West Systems Six10 glue because it's cheap (ish) and strong as shit. 3M DP 420 is supposed to be the best, but it's super expensive, and for my purposes not so necessary.