I made the seatstays using pretty much the same process as I did for the chainstays, but with carbon fiber cloth instead of bundles of tow. I plan on adding an aluminum insert for the rear brake to clamp into.
With the frame tacked together, I started making the lugs to reinforce the joints. I found that the only way I could get a decent seal in the vacuum bag was to enclose the entire frame. If I tried to pull a vacuum locally, the leak rate was too high to properly compress the joint.
This is what the reinforced head tube joint looks like after some sanding:
I did some work around the dropouts as well:
In an effort to make my vacuum bagging technique slightly more legitimate, I used peel ply and some resin-absorbing cloth around the seat cluster. Unfortunately, this joint had pretty severe seams around the edges, but I don't know whether they are due to the the cloth or the mediocre vacuum I was able to get.
This being a zero-dollar project, I was concerned about how I was going to get a carbon fiber fork. Molding one myself would have been very difficult, as the fork needs to interface with bearings and a stem, meaning it has to be more precise than I could manage with a foam mold. My leading idea was to find a large plastic billet, CNC out a female two-part mold for the fork at Edgerton, and positive pressure molding it, like how real bike parts are made.
Out of curiosity, I sent out a query to reuse-ask, to see if anyone on campus had a working or only slightly broken carbon fiber fork they would be willing to part with. I thought it was a bit of a stretch, but I got a response within four hours, from someone with a fork that had been crashed.
I sanded the area down to get a better picture of the damage. With the paint removed, it actually didn't look quite as bad. I sanded out all the cracks, which did not actually go all the way through the tube.
I applied a four-layer patch to the damaged area, starting with a small patch right over it. Each additional layer was larger than the previous one, so that the patch gradually increased in thickness from the undamaged to damaged area.
I sanded down the patch, and stripped the rest of the paint off the fork. I still haven't decided how to finish the surface yet.
With any luck, the frame should be finished within the week. In terms of components, I have everything except for a chainring, a front tire, a headset, and a stem, so I should be able to build up the bike shortly after finishing it.