I have been using this glue to repair all sorts of things, including smooth flat non-porous surfaces. It dries clear, and the hardness is about the same as epoxy. It really sticks and stays stuck. It's basically a contact cement. Glue both surfaces and wait a bit before joining them like 5 to 20 minutes, depending on how stuck you need it to be. It seems to stick really well to just about any clean, dry, oil free surface. In the US it can be had for a dollar a tube at Dollar Tree. It's a small tube, but I like that, because it travels well, and if the containment field is breached
you won't end up with either a large expensive gob of unusable adhesive and or a huge uncleanable mess.