I really really like this card, but I agree that it might be too strong. 5/6 for 6 is decent itself, so if you just go for ~4 Baron Blacksmith + 6 AW...
What about "Play any weapon from your hand without paying its quanta cost"? Or, as that might be too strong too, maybe specify a few weapons that thematically make sense (can be forged, that is). Just random brainstorm ideas.
/e: Alternatively, keep it that way, add: "Lose control of (sacrifice) Blacksmith when you play FW". Would balance the card and could also make sense thematically (He refuses to keep working for you if you chose filthy magic over honest physical labour. Or something. :p)