Bag of Iron Fermentation

This is a small bag that can be worn around the waist, when attuned the user can insert a mundane weapon for 1d4+1 weeks and begin to ferment it, enchanting the weapon into a +1 version of itself, if left inside for 1d6+2 weeks after the weapon will continue to ferment and turn into a +2 weapon. If allowed to ferment even further after that, after 1d12+3 weeks the weapon turns into a +3 weapon. If left In for an even further amount of time the bag will absorb the weapon and whatever you placed inside the bag will be lost. 

After a weapon is removed from the bag it can not be placed inside the bag again.

Notes: Container, transmutation