Test 8: A New Compression Tape for Wrapping Composite Tube Junctions

After the failure on test 6 where the electrical tape would slide out of position when compressing the layup, I started searching for a new tape to use. The tape needs to be elastic for good compression, but also be perforated and 'breathable' to allow excess resin out of the layup. The tape also needs to want to stick to itself when wet to prevent slipping, and the tape can't adhere to epoxy. Easy enough to find? So I test some items from around the house: athletic bandage wrap (ace bandage), cohesive bandaging like how the nurse sticks a cotton ball to your arm after taking blood, and polyester elastic waistband material.

I used PVC tube with a cap to mimic the head tube core's bearing race seats.
Carbon composite head tube bearing race test compression wrap test
Composite head tube test samples wrapped and vacuum bagged

Athletic ACE bandage used as compression wrap for carbon composite layup

Polyester waistband elastic used as compression wrap and bleeder for composite layup

Cohesive bandage used for compression and bleeder wrap for composite layup


The ace bandage and cohesive bandage stuck to the epoxy and bonded permanently. But the polyester elastic waistband worked perfectly. It removed easily and left a rough textured surface. The layup was tightly compacted, and the elastic didn't slide from the large diameter to the small. And, it seems, the elastic draws off all the resin and seems to eliminate the need for a bleeder. This worked extremely well.

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