i made a robot and i want to make a shell for it to cover all the wires and junk. i tried soldering aluminum together from an aluminum sheet but the solder wasnt sticking so i figured that didnt work. Does anyone know a good place to get like plastics i could use or any other good material you have used before?
You might be looking for Plastruct…
If you have a hobby shop near by, you might be looking for a product called “plastruct”. Basically, it is styrene sheets that model train folks use to build models. Its super cheap, easy to cut, uses super-fast cement to bond and is a great “shell” material.
Like Yahmez mentioned, in this case size matters.
You could go to the dollar store and find any number of containers that could be repurposed to be a shell for a robot. Along the lines of what CtC mentioned, there is a material sold at the dollar store here that is paper sheathed foamboard. I have seen it used to make a hobby RC trainer airplane. Being the dollar store everything is a dollar. 
http://makezine.com/makerhangar/
Check out episode 9
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