Re: Fun with power tools...
Solvent welding is using solvents to melt plastics - just like airfix kits etc, or the more grown up version, plastic pipes. It is, at a guess, made much like alcohol hand cleanser, but with a solvent instead.
The point is that it's a weld, not a glued joint. Works incredibly well sometimes - things that have broken off, e.g., join back together perfectly along the fault line (more often than any other way, at least). And it has the great advantage that if you try and use it on incompatible plastics it just evaporates without doing anything or leaving any residue.
Google solvent cement. Screwfix etc have it.