>I just wonder whether we would ever have a need to use the higher strengths >of 6061...wouldn't the 5005/6060 be more than enough?
Depends on what you are using it for. Coffee cup holder, sure. Control surface hinge bracket, not me. >I've used 5005 for my fuel tanks You are better off using the softer grades of aluminum for fuel tanks. 5052 is the best. It is one of the most weldable alloys and it won't crack and leak easily like the stronger alloys. Brian Kraut Engineering Alternatives, Inc. www.engalt.com
