Friday, March 15, 2013

Fendered Carbon

In my quest for somewhat creative ways to express myself recently, I have been making stuff. One of the things that I have been working on lately were fenders for our spring training, foul weather bicycles. Sure, you can purchase fenders, which we have done, but they typically need modification and are just flimsy plastic. I've actually built a set out of aluminum which we have mounted to the tandem. They are pretty nice looking and very functional but I had my sights on wooden fenders, as a point of style.

It is no surprise that the late winter and early spring weather in New England can get quite nasty. This year has been one of those years where the roads seem to be perpetually wet and gritty. The idea of fenders is to not only keep most of the wet, salty, road grit off of you but also to help keep it off from the person following you. early season training rides are often long, cold and miserable and are much more bearable with the company of others.

Cyclists ride closely behind each other in what is called a paceline, affording the followers a significant respite from the wind. The leaders then rotate in an organized and responsible fashion which allows the entire group to travel faster and more efficiently. On the bulk of the early season rides that we do, full fenders are mandated. Nobody wants to spend four hours getting salty grit sprayed in their face when it is 36 degrees out.

A couple weeks ago I started the project by slicing a chunk of VT ash that I had in my wood stash into the thin, about 1/4", strips which were an inch and half wide. I then stacked two of them together so that I could them through the thickness planer and meet the minimum head clearance. This worked OK and allowed me to get them fairly uniform and smooth while also reducing the thickness to about 3/16". From there I needed to get the raw strips bent to match the curve of the wheel. After thinking about it a bit I decided to make a clamping jig from an old road rim with wooden spacers screwed to it that would also serve as clamping points.

Bending the wood was the next task. The strips were thin enough to bend by hand but the trick was to get them to retain their curve. I knew that the best way was with steam. However, I didn't have a good means of steaming them and didn't feel like making a PVC steaming chamber so I simply soaked them in the tub for a couple of days. This worked OK but didn't really give the pliability I was hoping for. Next time I'll go ahead with a build a steam chamber. Anyhow, after sitting over the warm air register in the bathroom for a couple of days the strips were once again dry and had a respectable curve to them.

Next I trimmed and curved the ends, sanded and prepped them and added a decorative brand, which didn't really work all that well. As another project, I need to build a smaller brand that takes less effort to heat up. Once each individual fender blank was prepped it got a coat of lacquer sanding sealer and then a couple coats of clear lacquer. All of the hardware came from replacement fender parts that I sourced from Planetbike directly. Nice stainless steel rods and through mounting bolts. For the brackets I simply used raw 1/16" x 3/4" aluminum which you can find right at the hardware store. Aluminum 1/8" pop-rivets hold it all together.

The first set went on Cathy's new Chinese carbon cross frame. This was one of the Ebay purchases that I took a chance on. The frame is fairly nice but has some subtly nuances that made it a challenge to build, namely internal cable routing and some missing and unfinished parts. Hey, it passed Chinese QA though, according to the little gold stickers on the frame and fork. The end product turned out pretty nice and should make a nice fast spring trainer and cyclocross training/pit bike. It is also light, which shouldn't matter but in reality, does.

Back to the fenders, they took some fine tuning to get on but seem to be pretty good and certainly have a distinctive and classy retro-cool look. I'll work some of the bugs out for the next pair, such as the sizing and placement of the mounting brackets and the bending of the raw wooden slats. All in all a fun, usable project with respectable results.


tarbox said...

Hey Mike, they look nice. This is on my list of fun projects to. I was thinking about doing a three ply lamination instead of bending. Bending looks like it worked well. I like the rim as bending jig.


mkr said...

I thought about laminated as well but the most difficult part I've found, with the equipment I have, is getting super thin slats. Even cutting the ones I got was tough. My band-saw can't handle the hardwood with any precision and the table-saw isn't as accurate as I'd like either. If you could buy sheet veneer that would work great and glue up with Urethane or Epoxy and would be good to go.