Making do with improvised weapons or tools is great. Just make sure your GM doesn't have a degree in electronics or engineering. Or chemistry. Or happens to be a blacksmith.

You can argue quite convincingly to someone with no blacksmithing experience that with nothing more than a forge, tongs, a hammer, and an anvil, you can make a T-1000 series Terminator.

(By the way, if anyone gets away with this in an actual game, please let us know.)

Transcript

Luke: So wait, if you got searched, where did the laser sword come from?
R2-D2: I built it from spare parts in the slave workshop.
C-3PO: It's like the techno version of a shiv.
Luke: Spare parts?
R2-D2: Let's just say, there's an R4 unit out there that ain't showing holograms no more.
Chewbacca: But the restraining bolt?
R2-D2: Stopped me escaping, but it didn't stop me building things that have legitimate non-escape-related uses.
Leia: A laser sword?
R2-D2: It's more civilised than a blaster.
R2-D2: And makes a heck of a lot less mess when carving a roast.