In total there are 7 types of shield rims and each of type is used to asssemble the same type of the shield
Each type has different design (shape) but is the same from crafting point of view.
For any type of Rim, 2 ingots of any type are needed
You can use only the same shape rim to corresponding shield design (shape).
When the rim is acquired, cool it and drag to the shield to attach.