This is for when I too lazy to pull out the putty and try to squeeze it between seams. This works just as well, albeit it's much softer than putty. Since it's primer, it doesn't interfere with painting. Even if you're too lazy to primer again after using this, you can still paint over it with no fears. In fact it'll probably hold the paint better since it is a primer.

It's not plastic cement so DO NOT USE IT AS PLASTIC CEMENT. Things will fall off.