For this year Science olympiad, we have to build a robot that picks
stuff and places it into a jar. It has to reach about 5 feet and lift
objects up to 2-3 ounces.

I plan on making it fully automated, unlike last year one that won
the Illinois State Olympiad.

I want to make it's arms to be as lightweight as possible, from some
super thin material. But it has to be easy to work with. Something
like thin aluminum extruded square tubing or some such. Any
suggestions?

Again the arms only need to reach 5 ft and lift 2-3 ounces.

Thanks

i