are you going for a 'robot' in general
or a specific one, i.e. C3P0, Robby the Robot, Marvin the paranoid android?

Tumble dryer exhaust tube is handy for articulated joints, i.e. knees, elbows. Depends how much dosh you want to spend on it. And the fact it'll be fucking hot inside as well.
( Rotating Wobbly Hat That's not a banana. THIS is a banana., Sun 17 May 2009, 22:34, archived)

oh, and practise your 1980s 'robotics' breakdancing
while singing 'Domo Arigato Mr Roboto'
( Rotating Wobbly Hat That's not a banana. THIS is a banana., Sun 17 May 2009, 22:35, archived)

in fact that might work.
just get a silver jumpsuit and work on your characterisation/ posture / actions.
( Rotating Wobbly Hat That's not a banana. THIS is a banana., Sun 17 May 2009, 22:36, archived)