How did the FX guys at ILM come up with their droids?

[deathproof]

I must have watched every "making of" Star Wars show that came out when I was a kid. I was fascinated. But something I don't remember is talk of how they actually built the droids for the original trilogy.

Obviously some of them were actual legit robots (in a sense, anyway) like R5-D4 or the mine-sweeper droids who were remote-controlled and could roll.


Related, in the IG-88 build a fellow did he mentions getting a copy of the jet engine that made up IG-88's head.


So where did they get all their parts from? Did they just start visiting junkyards and picking up stuff? Surely they must have had some sort of base pieces for an R2-unit's body and head from somewhere. And how about other droids, like the treadwell with its multiple arms or the big black R1-G4 unit?


Where did they get the parts? Or how were they inspired to use certain parts? Surely someone must have talked about it or something. If a sound effects guy can discuss tricks for creating the sounds of laser blasts then there has to be an FX modeler out there who's talked about how they found the parts/inspiration/etc. for creating the droids - especially from ANH.


Any links to articles, interviews, etc? Not just for my own purposes of building replicas but I'm curious how someone can take a design and look at a thing and say - "there's the head. there's a foot. there's an arm." - it's been one of my shortcomings as a replica-builder. It's difficult for me to look at stuff like that and figure out a way to integrate it into a design.