Thank you for input everyone. Guess I'll be making a stunt then lol.
Something along the lines of "My Sword is My Shield"
brainstorm time!!!
I'd be leery of a Stunt that gave you armour dependent on the rating of your weapon.
First, there's no real connection between the ability of something to output damage and the ability to stop damage. Chain saws, for example, do really nauseating damage to people, but they're really unwieldy and would be awful to use to defend yourself.
Then there's the issue of Strength powers. Does being super strong and having weapon:6 fists really make you better protected? Not really.
If you want armour, wear armour or invest in Toughness. "I have a huge weapon:3 sword, so I've got armour:3," is beyond the scope of what Stunts should be doing.