I’m not sure why you guys are having so much trouble with extrusion. For our last two yearsour robot has been built entirely out of extrusion thanks to our great sponsor
item mindwest.
You can see our 2003 robot
here.
During the entire season we have made zero repairs to our robot structurally. At the Midwest Regional all we had to do was swap out a drill motor as far as repairs go. And then at IRI we never even needed to touch a wrench to the thing.
I am guessing that your problems reside in either using improper construction techniques or inferior extrusion.