I bought some Polypipe GFC100 Gap Filling Cement to stick some poorly fitting PVC pipe fittings together. I tested some on PLA printed parts and it makes a very strong bond.
I used it to stick these two parts together: -
It is a part to allow me to mount a vent that would normally go through a ceiling, on the surface of the ceiling. I am building a ventilation system for my garage workshop.
I made it from two separate parts to allow me to print it without support and a giving a smooth pipe so that I can clamp a flexible aluminium pipe over it and make a good seal.