Iron, sometimes called "mats" for short, is a very common and extremely versatile resource. Every item except Fuel needs 
Iron to craft. It's a commonly used and traded item, meaning you can trade Iron to other Spaceships for other items, if the trading Spaceship is seeking it.
Obtaining
Metal is gained from killing Sniper Bots, and sometimes from critical Ships. It can also be gained by shredding items in the 
Recycler.
