I know this has been posted many a time before, but maybe if we reiterate, then when people search, like you did, they will get a hit on it and get the answer they need.
For Smelting the person attempting to craft must have Three things:
1. Must have Training in Metallurgy from a trainer.
a. From lvl 0 - 4 a person can melt certain ores, and will receive experience for doing so. This person cannot make stock yet.
b. From lvl 5+ a person can cast Stock and Ingots, but will receive less experience or none at all for melting ore/ingots/stock
2. Must have the appropriate discipline in mind
a. The person must have accomplished certain tasks/acquired certain items in order to teach them how to craft.
b. In order to have the best experience, it is recommended that the person earn these things themselves, rather than purchasing them
3. Must have raw Materials
a. Currently workable ore (that I know of) includes Iron, Tin, Zinc, Silver, and Coal. Platinum was all "Mined Out" and Gold cannot be melted yet.
b. Different Materials can be combined to make new materials, but those formulas and combinations must be discovered on your own
Remember that this system is under constant modification/improvement, so the rules may change in the future. Last time my Metallurgy level was below 5, making ingots was not in the cards. The standard practice was to melt lots and lots and lots of ore, and basically sell it or throw it away, because once it was melted, it was useless for other things, like combinations. Not sure what it is like now.
OR
A person can team up with someone that wants to gain experience that is above level 5 and you can have an Apprentice/Journeyman relationship. One person melts the ore for exp. The other person casts the molten ore into ingots. This actually can work out pretty nicely, as Ingots and Stock are worth more than their components in the raw form.
Me, I just want to be able to cast my leftover lump of molten gold from July into an ingot. I think it would look purty as a souvenir
Edit!!! I just read the link from Laragorn, so some of the info I just posted may be invalid. Take a few weeks off work and it all goes to pot...
Keywords: Craft, Crafting, Metallurgy, Metalurgy, Iron, Molten, Ore, Zinc, Tin, Silver, Platinum, Moltin, Blacksmithing, Ingot, Ingots, Stock, Stocks