Gluing HIPS Parts

I’m the process of printing out a helmet on my Mini but due to the print size, I’ve had to split it up into several pieces. I’ve been looking around but haven’t found any definitive answers. Is there a recommended adhesive for gluing the pieces together?

I’ve used super glue (CA, cyano-acrylate) and it has worked well.

Judging from your thread’s title I get it that you use HIPS. In that case, you should look for plastic cements/solvents. A bit tricky to apply all because they are very thin. But the end result is “one” piece literally and not two pieces glued together. And for a helmet that is what you want.
Look for Weld-On #3 (very thin, like water, fast setting), for Weld-On #4 (also thin, slower setting), Weld-On #16 (thick like glue, weaker bond than #3 or #4) or any other brand you want.
The above cements work perfect on HIPS too.