Forging

In order to turn ore into bars you need to put them in the forge. Better ores require more time to smelt and use more ores to produce each bar. You can also add barrels to speed up or otherwise enhance the smelting.
You can add the forge to the World 1 town buying it for 10.

You can upgrade the forge as well in the upgrade tab. Upgrades include:

Upgrade	Bonus	Max Bonus
New Forge Slot	Opens +1 slot to smelt ores in per level	16 Available Slots (Lv. 16)
Ore Capacity Boost	Increases max ores per slot by 10 * (2 + level) per level	13270 Max Ore Capacity (Lv. 50)
Forge Speed	Ores are turned into bars +5% faster per level	+550% Forge Speed (Lv. 90)
Forge EXP Gain	+1% bonus EXP gain from using the forge per level (doesn't do anything atm)	85% Forge EXP Gain (Lv. 85)
Bar Bonanza	+1% chance to make an extra bar per level	+75% Chance for Multi Bars (Lv. 75)
Puff Puff Go	+1% chance for a card drop while afk (forge card chance, which are not from afk)	120% Card Drop Chance (Lv. 60)

Forge slots can also be upgraded in the Gem Shop via the Brimstone Forge Slot upgrade, which grants 50% faster smelting and 50% multi-bar for a slot.

Forge Times

Ores take time to turn into bars in the forge. The duration can be reduced via the aforementioned forge upgrades, using certain Oil Barrels, as well as with the Archer talent Smeltin' Erryday, which grants a chance at instant forge progress on each kill (AFK or active, including Multikill).

Ore	Time	Bar
Copper Ore x2	50 Seconds (50s)	Copper Bar
Iron Ore x4	150 Seconds (2m 30s)	Iron Bar
Gold Ore x7	350 Seconds (5m 50s)	Gold Bar
Platinum Ore x16	1000 Seconds (16m 40s)	Platinum Bar
Dementia Ore x40	1500 Seconds (25m)	Dementia Bar
Void Ore x100	2500 Seconds (41m 40s)	Void Bar
Lustre Ore x250	5000 Seconds (1h 23m 20s)	Lustre Bar
Starfire Ore x500	10000 Seconds (2h 46m 40s)	Starfire Bar
Dreadlo Ore x1000	20000 Seconds (5h 33m 20s)	Dreadlo Bar
Godshard Ore x15000	50000 Seconds (13h 53m 20s)	Godshard Bar
Marble Ore x4000	30000 Seconds (8h 20m)	Marble Bar

Forge Cards

Occasionally when removing finished bars from the forge, one or more cards will drop. The first tab of the forge (first four slots) drops Fire Forge Cards, while the second drops Cinder Forge Cards. The last two tabs do not drop cards. The type of bar smelted doesn't matter.

Oil

Oil may be added to a forge slot to boost Forging Speed or Extra Bar Chance:

Oil	Boost	Consumption Chance
Crude Oil	Forging Speed +15%	75%
Eco Friendly Oil	Forging Speed +10%	30%
Radioactive Waste	Forging Speed +30%	30%
Glumlee's Special Tutorial Oil	Forging Speed +999%	200%
Toxic Sludge	Extra Bar Chance +20%	60%
Magma Barrel	Extra Bar Chance +40%	50%
Plasma Barrel	Extra Bar Chance +60%	30%