How to Build an Automatic Smelting Plant in Minecraft

How to Build an Automatic Smelting Plant in Minecraft

An automatic smelting plant, or furnace array, is a build made of several furnaces that smelts a resource in whole stacks instead of loading each furnace by hand. Material and fuel spread themselves across every furnace, and the finished product flows into a single chest. This version relies on two hopper minecarts, so it does without complex redstone contraptions and can be built in one pass. The scale is up to you — from four furnaces for smelting ore or sand in Minecraft to a long row.

What You'll Need

The number of hoppers, furnaces, and rails depends on how many furnaces are in the row. 4–8 furnaces is enough to test the build.

Per furnace:

Frame and automation:

Layout of the gathered materials 

Step 1. Output Chest and Row of Hoppers

Place a double chest — the finished product will collect in it. Run a straight row of hoppers out from its side face: hold Shift and click on the previous hopper to attach the next one instead of opening it. There should be as many hoppers as planned furnaces. All of them should face the chest and will feed it the smelted output.

Output chest and row of hoppers 

Step 2. Furnaces on the Hoppers

Place a furnace on top of each hopper. The bottom hopper pulls the product from the furnace's output slot and carries it down the chain to the chest. Blast furnaces work twice as fast for ore and metals, smokers for food; a regular furnace smelts everything but slower than both.

Step 3. Fuel Hoppers

Go behind the row of furnaces. Attach a hopper to the back face of each furnace (Shift-click toward the furnace). A hopper entering a furnace from the side or back fills the fuel slot. This is the second row of hoppers, parallel to the first.

Row of furnaces on hoppers 

Step 4. Input Hoppers on Top

Place another hopper on top of each furnace — this is the input for material to be smelted. Now three hoppers surround each furnace: the top one feeds material, the back one feeds fuel, and the bottom one takes the result.

Three rows of hoppers around the furnaces

Step 5. Rails Above the Hoppers

Lay rails on the top hoppers along the whole row, then do the same on the back fuel hoppers. That gives you two parallel rail paths. Every rail resting directly on a hopper must be a regular rail.

Step 6. Far End: Minecart Return

At the end of both rows farthest from the chest, stack blocks into a step. On the step below that block, place a redstone torch — it powers the block holding the rail, keeping the rail active and bouncing the minecart back toward the chests.

Block steps and redstone torches 

Step 7. Near End: Loading and the Lever

Near the output chest, raise both paths two blocks up with blocks and place a powered rail on top of each. Above each of these rails, place a double loading chest: above the material row, a chest with the resource to be smelted; above the fuel row, a chest with coal, charcoal, or other fuel. Hang a lever on the block holding these rails — it turns the launch on and off.

Two rows of rails with powered rails at the ends

Step 8. Hopper Minecarts

Place two hopper minecarts on the powered rails at the near end — one for each path. Each minecart will sit under a loading chest and pick up items from it one at a time (a full stack in roughly 12 seconds).

The fully finished smelting plant 

Step 9. Starting It Up

Pour material into one chest and fuel into the other. Flip the lever: the powered rails launch the minecarts, they roll over the rows of hoppers, and each hopper under the path pulls one item out of the minecart. That's how material and fuel spread evenly across all the furnaces, while at the far end the torches bounce the minecarts back under the chests to refill. The smelted output drops down through the bottom hoppers into the output chest.

Conclusion

Smelting with minecarts solves one problem: processing a resource without manually shuffling items and without wasting fuel on partially filled furnaces. It's well suited to survival play, when you need to regularly smelt stacks of ore, sand, or food and don't want to deal with redstone. If you need maximum throughput for 12+ furnaces, a hopper array with comparators is a better fit.