Electronics - Hyperspecific and mediocre

Tubes were the first composite parts I made. The two methods I have used to make tubes are sleeves and convolute wrap.

Sleeves are biaxal woven "socks" of composite material which expand and contract like a chinese finger trap. This means that a single size of sleeve can make a multitude of sizes of tube, or conform to compound curves such as for tapered layups. I slide these sleeves over a mandrel and add resin for each layer. This results in a tube with tubes with fibers running around the tube, similar to a filament wound tube. Wind angles vary based on sleeve size vs mandrel size, but are generally in the 40-70 degree range.

I convolute wrap tubes in the standard way, by wrapping a continuous ply of fabric around the mandrel and adding resin as each new part of ply is added. This results in tubes which are stronger in bending due to the more axially oriented fibers, but weaker as pressure vessels and in torsion.

Both methods are released from the mandrel with a layer of polypropylene plastic film between the layup and the mandrel. The layer of plastic film acts as a release film, allowing the layup to be separated from the mandrel after curing.