I got my head tube finished up and it seems to be pretty solid. I used a couple of layers of fiberglass sleeving with one sleeve of carbon on top. Supposedly the fiberglass has a bit more give to it and isn't prone to cracking so easy whereas the carbon is lighter and stiffer. I noticed on some of the carbon tubes that I bought in the past that they had a layer of glass on the inside, but I mainly did it because its cheaper to experiment with. I can't wait to get my madrel for the tapered head tube finished, I'm itching to build one scratch.
Rocket science huh? Not exactly. While most custom carbon frame builders are using prepreg carbon, vacuum bagging, and ovens, I'm still in the learning stages. While I do plan on vacuum-bagging the frames I'm still doing wet layup, and while I could've easily used a vacuum bag on this head tube it would almost have been a waste of time. Back when I built my first carbon frame I spoke to one of the technical guys at West Epoxy Systems and he told me that you could actually get more pressure per square inch on certain parts wrapping them by hand with rolls of shrink-wrap or whatever its called that they use to wrap pallets and luggage with. I think its called stretch film. This is definitely one of those applications where I think its beneficial and a time saver. After the laminate is layed down I wrap it with some nylon peel ply and then the breather cloth. I actually get it pretty tightly compressed before ever even wrapping the stretch-film. Anyway, its actually the way I built my first carbon frame, it does a good job but it just doesn't look as professional as vacuum-bagging.
This is how it turned out. The nylon peel ply soaks up all the excess resin and it leaves it with a dry look. Its much stronger than the original tube that I started with, almost feels like steel.
Not worried about the bearing cups being secure anymore, it seems pretty tight.
I decided to go ahead and clean them up a little before starting because they had a little excess epoxy inside. On the bottom I tried to cut it too fast and you can see where the cutter started to jump a bit. Once it starts it'll never stop, it'll just keep getting worse. Ever heard the expression "slow down to go fast"? It doesn't matter because its all very level and the bearing will sit down in there just fine. The first time I had this happen was with aluminum bearing cups and it was worst than this but it still works flawlessly, no worries. The main concern is that the diameter of the bearing is tight with no side to side play. These cups need very little cleaning up anyway coming straight from the supplier. A little grease should make it perfect.
For some reason these cutters are a favorite of mine. They haven't seen much use yet. They kind of remind of nice jewelry that never gets worn. I don't have any nice jewelry to stash away only these cutters.
I got the seat tube and down tube cut this afternoon and the UPS man just dropped off my chain stays so I'm gonna go unwrap those and check them out. Thanks for stopping by. Here is a little clip of the Cyfac frame company, out of France I believe, doing a little wet layup. They make it look too easy. Don't believe it. Enjoy.
After watching this clip for about the 50th time I'm starting to realize that wet layup is an art form, very similar to brazing, and it makes me want to get better at it, however, I know that using the prepreg is much more user friendly and probably the most efficient. Personally, if both processes are done correctly and with care they should both produce a good frame. Stay tuned. Chao.