How do I open the golden padlock?

Hint 1 of 10:

You need a golden key

Hint 2 of 10:

You need some molten gold and a key mold

Hint 3 of 10:

If you don't already have a bar of gold, see another hint in this
section.

Hint 4 of 10:

If you don't already have the key mold, see another hint in this
section.

Hint 5 of 10:

Melt the gold in a cauldron over a fire

Hint 6 of 10:

Make the cauldron by using the ring on the copper ball

Hint 7 of 10:

The ring is in the skull in the back room