Light clamps to assemble your composite tubes!
8 different models for 14mm, 15mm, 16mm, 18mm, 20mm, 25mm, and 30mm Outside diameter tubes
See the pdf file which describe the different assemblies.
The best tubes for these kind of tubular structures are technical tubes (Filament winding) because of their compression strenght. The standard tubes are also convenient but be careful when you screw the elements together.