I like @NPC_X 's response over in this post. [feels like between these two posts we’ll soon have enough material for another Net Book]
To quote:
I never liked the rules for ‘inferior’ materials. ‘Inferior’ is a relative term; on Athas, these materials are the standards. It’s metal weapons and tools that are superior to them - hence, I believe they should be boosted up, while the ‘inferior’ weapons should be the unmodified rulebook equipment.
Why not make your copper weapons +1, bronze or iron weapons +2 and steel weapons +3? or some such.