kettle, cauldron, iron pot
釡 centers on a large metal cooking vessel: a kettle, cauldron, or iron pot used for boiling or heating.
釡 is a variant form of 釜, which combines 金 (metal) with a phonetic element. The exact historical development of the 釡 arrangement is uncertain, but it likely represents a metal pot.
The right side is 金 (metal), and the left side looks like a pot with a lid and handles. Picture a heavy metal cauldron made of gold, bubbling over a fire.
For フ, imagine a huge cauldron full of food: the sound of bubbling stew is 'fu fu fu', and that bubbling cues the reading フ.