gluing filament ends together?

has anyone tried gluing, for example, 20cm lengths ABS filaments together end to end with something like a dot of superglue? - to print with rainbow colours?

or to just feed in a length of different colour as previous filament passes through idler??

regards, Stefano

Filament can be spliced by melting a small section of the two ends:

The “Pallet” is a machine that automatically splices 1.75mm filament: