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How do I smelt my first iron?
- 1
Craft the Furnace
Put 8 cells of any rock in a ring around an empty middle cell of the crafting grid (16 voxels each).
- 2
Place it and open it
Place it like a chest, then right click it. Four slots: input, reducer, fuel and output.
- 3
Fill it
Iron ore in the input slot, coal or charcoal in the reducer slot, coal, logs or planks in the fuel slot. Breaking a 1 m block of ore gives 64 voxels: four ingots.
- 4
Wait and collect
Each iron ingot takes 12 s of fire. Take the ingots from the output slot.
How to get it
A ring of eight cells of rock around an empty middle. Set it down, give it fuel (or a powered cable), the ore in the input and coal or charcoal in the reducer slot.
What it is for
Iron, copper, gold, titanium and lithium ingots, steel, charcoal, glass, terracotta, bricks, cement, silicon and the Raisonite alloy.
Why it exists
Fire transforms matter: the Furnace is the door to the iron age, and the only kiln of the game.
Which ore gives which metal?
Every row takes 16 voxels of ore (one grid cell) in the input slot and coal or charcoal in the reducer slot (one charcoal counts as one voxel of coal).
| Input | Reducer | Result | Time |
|---|---|---|---|
| Iron ore | 4 coal | 1 iron ingot | 12 s |
| Copper ore | 4 coal | 1 copper ingot | 10 s |
| Gold ore | 4 coal | 1 gold ingot | 10 s |
| Titanium ore | 8 coal | 1 titanium ingot | 20 s |
| Lithium ore | 4 coal | 1 lithium ingot | 12 s |
| Bauxite (on a powered cable only) | — | 1 aluminium ingot | 15 s |
| 1 iron ingot | 2 coal | 1 steel ingot | 15 s |
How long does fuel burn?
A machine lights one cubic metre (64 voxels) of fuel at a time, or what is left in the slot, and only when it has work to do. What burns keeps burning down. Fuel only heats: ore still needs coal in the reducer slot.
| Fuel | Burns |
|---|---|
| Coal | 60 s per cubic metre |
| Charcoal | about 0.94 s each (64 charcoal = a cubic metre of coal) |
| Logs and planks | 12 s per cubic metre |
| Stick | 0.75 s each |
| Bitumen | 80 s per cubic metre |
| Bucket of lava | 100 s (a full bucket) |
| Bucket of crude oil / kerosene / petrol / diesel | 20 s / 40 s / 50 s / 60 s (a full bucket) |
| Cylinder of methane / natural gas / hydrogen | 30 s / 30 s / 25 s (a full cylinder) |
Set on a powered cable (2 kW), the Furnace burns nothing at all: build a generator or solar panels and it runs on electricity.
What is steel good for?
- Steel armor and the steel sword: see weapons and armor.
- Steel plate in the metal mill, large pipes, bolts (8 per ingot in the grid), coil springs and cogwheels (4 ingots in a ring give 2).
- Reinforced concrete: a steel ingot in the concrete mixer's additive slot.
What else does the Furnace fire?
The same Furnace is the kiln. Put these in the input slot (fuel as usual):
| Input | Reducer slot | Result | Time |
|---|---|---|---|
| 16 logs (any wood) | — | 16 charcoal | 4 s |
| 16 sand | — | 16 glass | 8 s |
| 16 clay | — | 16 terracotta | 8 s |
| 16 clay | 4 sand | 2 bricks | 8 s |
| 16 clay | 16 limestone or chalk | 2 cement | 10 s |
| 16 sand | 8 coal or charcoal | 1 silicon | 20 s |
| 2 gold ingots | 1 raisonite shard | the Raisonite alloy | 10 s |
Terracotta pieces (flower pot, vase, jug, bowl, plate) are then shaped from terracotta at the crafting grid. The Raisonite alloy is the first forged alloy.
Questions
Do I have to wait next to the Furnace?
No. The server runs every machine, even when its chunks are unloaded. Fill it, go exploring, come back for the ingots.
Can I burn wood instead of coal?
Yes, in the fuel slot (logs and planks: 12 s per cubic metre). The reducer slot always wants coal or charcoal for ore.
Where is cast iron?
Gone since the October update: iron ore gives iron directly. Old cast iron in a save turns into iron when the world loads.
Where do I find ore?
In veins along cave walls and in giant lodes. See finding ores and the caves guide.
Updated