That'd be relatively ineffective plastic fusing if tried with acetone. It's done properly with a MEK, usually with acrylic in solution to thicken it up a bit. It's also called solvent bonding.
Plastic welding involves compressed air, heated in the welding gun and welding rod made of a compatible plastic. Strips of Mac or PowerBook Case Plastic for our uses.
< reminds self to get the rig out to practice and take some pics of the MacWelding process >