Incognitotj, if you'll go and visit your local plastics store, you'll find the right stuff and TOOLS...
I made the drive bays, etc. in my computer using plexi. I learned that the best way to join the stuff is by putting the chemical
(prolly the stuff that Vagabond recommends
) into a hypodermic-like injector (cost: $6) and it flows PERFECTLY along the joint!
This method joins it and looks good, too. Your local plastics retailer can show you, it's very easy!