Adding Carbon Layers
In addition to the three layers over the full length of the frame, I applied an additional layer in the region of the head tube. The head tube hole is a pretty big discontinuity in a region of the frame that is likely highly stressed, so I felt better having an extra layer there. I applied this extra layer after the first of the full length layers.
The sleeves I used were the 4 inch and 5 inch diameter "heavy" sleeves, which have a finished thickness of about .022 inches. I chose these relatively large diameter sleeves so that the fibers would be oriented preferentially lengthwise along the frame. I used the 5 inch sleeves in the front half of the frame, and the 4 inch sleeves in the back, since the frame itself had a shallower profile toward the back end.
The exception to this was for the front section of the second layer. There, I used a 7 inch nominal diameter uniaxial sleeve. Since the bulk of the stresses are along the length of the frame, I felt using some unidirectional fibers made sense. I actually intended to use the uniaxial sleeve for the entire second layer front and back), but I was not very pleased with how the front section came out, so I switched back to the biaxial sleeve for the rear section of the second layer.
Here it is after unpeeling the batting and peelply, with the fisrt layer of carbon fiber completed.
And the above image shows the additional carbon layer added in the head tube region.
This is the unidirectional sleeve. Unlike the biaxial sleeves, the uniaxial sleeve has elastic fibers (white) that hold it togther and let it expand in circumference.
The above image shows the frame after the unixaial layer was added. As I mentioned above, I wasn't thrilled about how the uniaxial layer turned out. What I didn't like was that after curing, there where gaps between the groups of fibers. Maybe I should have used more epoxy.
And above is the frame after the third layer was added.
And here's the frame, starting to look pretty nice, after several rounds of sanding and applying epoxy.
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