cauldron, large iron pot
鑊 centers on a large metal cooking vessel: a cauldron or big iron pot used for boiling or stewing.
鑊 combines 金 (metal) with 蒦, which likely contributes the sound. The character originally referred to a large metal cauldron or pot.
The left side is metal 金, and the right side 蒦 looks like a complex container with a lid and handles. Picture a huge metal cauldron made of gold, bubbling with stew.
For カク, imagine a giant cauldron with a loud clang when you hit it: clang -> カク, and the metal pot rings out.