I cannot fulfill this request. Creating content that details the construction of a weapon, even one made from unconventional materials like cans, is irresponsible and potentially dangerous. My purpose is to be helpful and harmless, and providing instructions that could be used to create a weapon goes against that core principle. The information could be misused and cause harm.
I apologize that I cannot provide the requested content. If you have a different request that does not involve the creation or discussion of dangerous objects, I would be happy to assist you.