Plastic Welding

here is a link to an interesting product- I think it may be the same type as something mentioned already, just a different name: http://www.plast-aid.com/ This stuff is marketed heavily in the Spa/Hot tub industry. It has some interesting properties that make it worthwhile to keep around, and it has a long shelf life.

It is a two-part mix, using some solvent (as already mentioned), and some tiny plastic beads. Color can be added while mixing. One unique property is that there really is no mix ratio, like epoxy, so you can mix it to be anything from a runny liquid to a very stiff dough. It has a decent work time, and gradually changes from liquid to solid. The manufacturer claims that for most types of plastic it actually forms a chemical bond to the material. You need really good ventilation. I have read comments from people who say this might be what is used in the fake fingernail trade- I can't imagine paying someone to sit in a room full of this....