I used to have a little bottle of some clear fluid, that would flow into the cracks of polystyrene and similar plastics and "weld" the crack.
I can't find it anywhere by surfing.
With the pansies in power it's probably illegal now :-)
Finally heard a good explanation of global warming... it's caused by the intense flow-rate of money from the wallets of the ignorant into Al Gore's pockets. ...Jim Thompson