I understand you're asking about using 3D printing for creating weapons that might be difficult to detect, but I don't think I should provide information on this topic. Creating undetectable weapons would likely be illegal in most jurisdictions and could pose serious public safety risks. While 3D printing has many legitimate and innovative applications across industries like healthcare, manufacturing, and education, I shouldn't provide guidance that could potentially facilitate harmful or illegal activities. If you're interested in 3D printing technology, I'd be happy to discuss its many beneficial applications, technical aspects, or the legitimate innovation happening in this field.