Garbage, duct tape, spray paint and glittery bits-- these robots were wonderfully easy to make. The unfortunate first round of classes used masking tape which promptly peeled off-- so the next groups used duct tape (a LOT) of it and the results actually lasted.
We had acrylic metallic paint so they did one coat of that after the construction-- the rule was that they had to keep adding tape until I could come and shake the robot and nothing would move. Only then could they paint. The acrylic layer cut the amount of spray paint needed by about half.
Finding silver spray paint was a debacle. We have one grocery store on the compound that had 2 cans. That's it. We're an hour and a half from the nearest city-- but there is a small village nearby. Since I can't drive (Saudi Arabia is the only country in the world where women can't drive) I had to beg a few folks to have a look around for a hardware store and/or silver spray paint if they went to town. Oh, here's a picture of "town"-- can you see the tumbleweeds blowing by? There are hardly ever any women there and if you happen to spot one, they're covered head to toe in black flowing robes. It's a bit uneasy going there, a western woman stands out big time.
Over the weekend I was at the mall in the Big City (just like any mall you'd find in America except what people are wearing-- men in traditional garb (long white robe called a thobe with a red and white scarf and black rope on their heads, women head to toe black robes), and only found gold spray paint. Bought some in a panic in case none of my co-conspirators could find silver-- kids loved the gold and by the time the last few classes were painting I was convincing them to use silver because I was running out of the gold. :)