Filament join cover

I followed function.3d tutorial on how to join PET filament on these: cardboard spools

Using small tubes to cover and protect welded joints works great, but it was annoying for me to eject filament from the printer from time to time to slide them off. 

So I built ones that can be assembled on filament at any point and taken off at any point.

The design is optimized to print flat on printbed, it allows parts to slide into each other.

For stable print of the arch overhang, just use a thin layer. 0.1 mm worked for me.

Adjust your tolerations as needed. Scaling the outer part by a couple % should help.