Which PVC cement?

[Delphinus]

The clear cement has a little flexibility to it and that's why it's better to use with flex. Although in a pinch I don't think it really matters, it's only if there is a fair amount of pull on the pipes (that you would need to worry about it). The only thing is the grey cement and the purple primer from HD/Rona/etc is messy. Once a pipe has the purple stuff on it it's there forever and ever, so I don't like to use it. And heaven help you if your spouse discovers you've spilled the purple stuff on a carpet.

The clear stuff is invisible so makes for cleaner looking pipe work. For that reason, I use the clear on both rigid and flex PVC. I get mine at Western Pump.