The transition of the composite part at the head tube bearing rests will have a considerable amount of geometric shape changes to accommodate. It is also a highly stressed area and will need to be compacted properly. Test 6 investigates how the electrical tape and vacuum bagging will perform in this area.
Test 6 used the same limitations of layers of test 5, and general wrapping style with the electrical tape. I also tried applying the peel ply in smaller strips to better allow the bag to compact the layup at areas not compressed by the tape.
This did not work. This test revealed a serious problem with the electrical tape method. The tape, when wrapped around a shape, tends to pull itself toward the smallest diameter. When wetted with resin, the tape slides very easily against itself. So the tape is not able to compress the layup at a sharp geometric change: it simply slides down to the smaller diameter. Below shows the tow I wrapped around the diameter change mimicking the bearing race seat... it was pulled away by the tape slipping.
This is just not working. The geometry of a bicycle frame tube intersection lends itself better to the tape compaction. However, the tape leaves a poor surface finish for subsequent layups and (far more importantly) is not able to accommodate geometric changes in the core.
Test 6 used the same limitations of layers of test 5, and general wrapping style with the electrical tape. I also tried applying the peel ply in smaller strips to better allow the bag to compact the layup at areas not compressed by the tape.
This did not work. This test revealed a serious problem with the electrical tape method. The tape, when wrapped around a shape, tends to pull itself toward the smallest diameter. When wetted with resin, the tape slides very easily against itself. So the tape is not able to compress the layup at a sharp geometric change: it simply slides down to the smaller diameter. Below shows the tow I wrapped around the diameter change mimicking the bearing race seat... it was pulled away by the tape slipping.
This is just not working. The geometry of a bicycle frame tube intersection lends itself better to the tape compaction. However, the tape leaves a poor surface finish for subsequent layups and (far more importantly) is not able to accommodate geometric changes in the core.
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