Somewhere between woodwork and framebuilding: bamboo bike #2

VERY, VERY NEARLY FINISHED

So life has a way of filling up what you thought was free time, and I've not quite finished yet. But it's tantalisingly close, probably closer than you could easily tell from photos on the net and I'm going away tomorrow for three weeks, so here's the nearly finished product, and how I got there...

Polishing the CF, a dead end...
The CF was all in place and sealed, so I just had to get it to a finished state. I decided I would polish the epoxy - first I smoothed it off very lightly with wet 1200 grit wet and dry, and then I polished it with Autosol.

Polishing process by comatus1649, on Flickr

Autosol is a metal polish, but it's pretty good at this as well. I used loads of it, but it came out nicely, better than I had expected in fact:

Polished CF by comatus1649, on Flickr

And it looked better than that in really life. Unfortunately the finish didn't last very well - it seemed to be mostly down to the protective coat that Autosol deposits, and it dulled quite quickly. I also found that the bottom of the BB was getting scuffed pretty easy, so I decided that I wanted to put another protective coat on top. I was going to clear coat the epoxy, but decided not to because of its tendency to yellow, peel and generally be a bitch to get right in the first place. So as I was going to be using Gorilla Glue to seal the bamboo I decided to give that a go (cleaning off the polish residue and roughening it up with 150 grit first), and I was pretty pleased.

Sealing the bamboo

As mentioned before, bamboo has a naturally waxy finish which protects it for a while, but decays after about 6 months when it's dead, so I decided to take it all off (hell of a job) and replace it. I chose to use Gorilla Glue because I had it about, I knew it was very UV-resistant and tough, and because it's been used a little in bamboo rodmaking with good results. It is a bit finickety to use, and I'm not sure whether I'd be bothered with it again. I would probably just use spar varnish. However, it did come out well. You have to apply it very very thinly - I used a slice of washing up sponge to put it on very lightly. Put on too much, and this happens:

Ooops by comatus1649, on Flickr

The same foaming action that makes it great as a glue is not what you want for a finish. It's also worth adding that you don't wet the surface as you would if you were gluing it - the humidity in the air is enough to make it go off very slowly, leaving a nice smooth, glossy and hard finish.

Gorilla glue drying by comatus1649, on Flickr

Bottle bosses
To make this bike as much of a jack of all trades, I wanted to put bottle bosses on. I wish I had bought more, but ended up only putting enough for one cage on the downtube. I nearly just put one on the seat tube because I personally think that position has some advantages, but I didn't have a spare cage and bottle to test and I was worried about clearance with the sloping top tube. So one in a conventional location it is.

I also put two other bosses in strange locations for other purposes - one is on the back of the seat stay wishbone - this will provide a very nice neat way of mounting a rear rack. Drilling a hole here was incredibly difficult but now it's in it actually looks quite neat. The second odd one was on the back of the seat tube, at the point where the wheel will be closest to it. My rationale - I want to run full mudguards because life's too short not to. But I didn't put a chainstay bridge in for cosmetic and ease of wrapping reasons; this boss here will allow me to bolt the mudguard to the seat stay about 5 inches above its end (I'll have to drill another hole unless I have the mudguard ending early). I will have to see how this works out - the rear wheel clearances are relatively tight so it should work alright, and look nice and clean. Of course, it might be a terrible idea. But there have been 6 or 7 things I've done on this bike for the sake of experimental innovation so that I will know not to do them again (or potentially know they're a good idea).

The holes for the bottle bosses were drilled with gimlets first and then with an awl. I thought this would be the most gentle way but still cracked the sodding downtube very slightly. Take it very easy, boys and girls. I don't think the crack will spread but I will add a little more glue to seal it.

So this is where the frame is, essentially finished:

Finished (nearly) by comatus1649, on Flickr

When I get back, I'll finish it totally - one more go with 1200, then more Autosol, then beeswax or similar all over. That should give me the durable shiny finish I want... For now you'll have to be content with smartphone pics, but when I'm happy with it I'll get some proper arty ones. And then it's a matter of building it up (Christmas is on the way, thankfully...)!

Thanks for reading!
Ben