similar to christmas tree lights question...

The two halves are welded together. Usually this is ultrasonic welding. When repairs are done the halves are solvent welded.

power supply in order to mend a wire (battery long

also worked loose exposing the braided wire. This

moulded in one go, or is there some hidden way they

Often appear to be made in two halves bonded together with epoxy adhesive.

My advice is not to attempt to cut it open if it is working. Instead, tape the cable to the PSU in such a way as to take the strain off the damaged part where it emerges from the PSU

Agree with others that they're generally welded shut or solid potted with epoxy. Since it's a Dell, I'd highly recommend replacing it with their auto/air travel adapter, so long as your laptop requires up to 65W and has the barrel connector with the 3rd pin in the centre.

(ignore the £20 knock off and stick with the £38 genuine ones)

They're 1/2 or 1/3 the size and weight of the PA10/PA12 adapers, come with cables to run from 240V, 12V cigarette lighter and plane/ship power sockets, have an extension lead for the low voltage cable. They run far cooler too.

Review how you handle the flex as you may be twisting it too much!!!

In similar vein, I recently levered apart the two halves of a dead Sony PSU quite cleanly. Mixture of clips and welding. Had I to make a similar repair to yours I'd have either glued and cable tied/taped the case back together or just bought a big enough box to rehouse the innards at Maplins.

Why would you want to rehouse the innards at Maplins?

:-)