Fusing Gear

Overview
All weapon and armor obtained initially start at level 1 and can be leveled by fusing other types of gear into it. This increases the stats on the gear, making it an essential step in increasing the party's strength.

Gear fusion is done by selecting the gear to be fused, referred in-game as the "base" gear, and then selecting a maximum of 10 gear to be fused into the base at a time. The higher the maximum level of the gear, the higher the gear EXP required to max the gear. Generally, fusing higher rarity gear gives more EXP. Spheres give the most EXP compared to all gear of the same rarity. In fusing gear, fusing together gear of the same type gives 5 times regular EXP. Gear fusion requires gald, and the higher the level of the base gear, the higher the cost of fusing. It is recommended for players low on gald to level their equipment to the maximum level in one fusion.

A unique part of gear fusion is limit breaking. Much like unit limit break, when fusing gear of the same name to the base gear, not only will the gear get EXP, but it will also limit break (LB) the gear once. Most gears can be limit broken up to five times, which allows their stats to increase past their maximum level. Limit breaking can still be done even when the base gear is at maximum level.

Fusion EXP
Gear rarity determines the amount of EXP given when fused into other gear. Gear level does not impact the EXP given. Gear type, however, gives a bonus of x5 EXP when the same types of equipment are fused together.

Upgrade Material EXP
Upgrade materials are always under the armor type.

Metal EXP
Grants the lowest amount of exp, and will always be classified as armor.

Special thanks to /u/TNinja0 of Reddit for the data collection!