you can use regular model glue (e.g. Testors in the orange or blue (non-toxic) form. You can also use the solvent-type glues like Tenax-7 that actually melt the plastic. They set a lot faster, but come with a whole host of precautions. I would use those in a fume hood or spray booth that vents to the outside if you are going to use them on a regular basis.
Andrew