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"Rust" Furnace and Refinery Stack Efficiency Guide

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A veteran "Rust" degenerate with 2.5k hours, a rock, and a dream.

Smelting Guide

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Resource Efficiency When Smelting

Rust is all about efficiency. Getting ahead and staying ahead takes efficient use of your time and resources to stay competitive. It's best if you're efficient with PvP and get all your loot from other players. However, everyone still needs to be efficient with their farmed resources.

When it comes to using your furnaces and refinery to smelt ore and crude, there are a few things to consider. One is how efficient you are with your wood usage and smelting slots, while the other is how efficient you are with your time. The more time you spent managing your furnace, and the less time your furnaces are running, the less efficient you are. It tends to be much more important to be time-efficient in Rust than resource-efficient. When it comes to furnaces, this often means it's better to chop down an extra tree or two if it means you don't have to remember to continuously re-start your furnaces every 30 minutes.

Large Furnace - Lazy and Time Efficient Stacks

Metal Ore - 7000 Ore + 5000 Wood

  • Frags per Min: 42
  • Frags per Wood: 1.4
  • Check-in Time: 2.8 Hours (Great for appearing online)

Load 5000 wood and 7000 metal ore into the furnace, but split the last stack of 1000 ore with your middle mouse button into 2 stacks of 500 each. Then split one of the 500 stacks into 2 stacks of 250 each. Start the furnace and in a little less than 3 hours you can come collect 7000 metal frags. This is the easiest way to cook metal ore in large furnaces. It does cost more wood per metal frag compared to the most efficient method. In fact, it's technically half as efficient going from 2.8 metal frags per 1 wood at the most efficient down to 1.4 metal frags with this method. But for the cost of 2 and a half more trees, about 50 seconds of chopping, you can skip multiple furnace management sessions and manually entering specific ore amounts. Plus, you'll likely have more uptime on the furnace unless you're checking back in on them every 30 minutes.

Sulfur Ore - 8000 Ore + 2500 Wood

  • Sulfur per Min: 96
  • Sulfur per Wood: 3.2
  • Check-in Time: 1.4 Hours

Similar to above, drop 8000 sulfur ore into the furnace. Split the last stack into 2 stacks of 500 each. Load 500 wood into the furnace and start cooking. When the 500 is burning, add 2000 more wood in by dragging the wood over instead of right clicking it to avoid stacking the burning 500 wood into 1000. Come back in a little less than an hour and a half and collect your 8000 sulfur!

Smelting Screenshots - Full Cook

Frags per Min: 42, Frags per Wood: 1.4, Check-in Time: 2.8 Hours

Frags per Min: 42, Frags per Wood: 1.4, Check-in Time: 2.8 Hours

Sulfur per Min: 96, Sulfur per Wood: 3.2, Check-in Time: 1.4 Hours

Sulfur per Min: 96, Sulfur per Wood: 3.2, Check-in Time: 1.4 Hours

Large Furnace - Wood and Speed Efficient Stacks

On the other side of the spectrum is a different kind of optimization. Keep as many slots smelting as possible to maximize wood efficiency as well as how quickly you can smelt your ore. The cost is that you'll need to check in on the furnaces very regularly so it's really only viable if you're in base building, organizing, crafting, etc. or otherwise doing other things.

Metal Ore - 15 Stacks of 67+

  • Frags per Min: 90
  • Frags per Wood: 3
  • Check-in Time: 10 Minutes

Fill your furnace with 1000 wood and 15 stacks of metal ore of any quantity 67 or higher. Come back every 10 minutes to clear metal fragments and charcoal. It's significantly more tedious, but you will get a whopping 3 metal fragments for every 1 wood you spend. You'll also be generating 90 metal fragments per minute compared to the 42 metal fragments per minute you get with the previous setup. Still I believe this is not the ideal way to smelt, but there are situations where it makes sense to do this.

Sulfur Ore - 15 Stacks of 67+

  • Sulfur per Min: 180
  • Sulfur per Wood: 6
  • Check-in Time: 5 Minutes

Same thing as above, however you'll need to clear sulfur and charcoal every 5 minutes. You'll be generating 180 sulfur per minute instead of 96 sulfur per minute in the previous setup.

Smelting Screenshots - Active Management

Frags per Min: 90,  Frags per Wood: 3,  Check-in Time: 10 Minutes

Frags per Min: 90, Frags per Wood: 3, Check-in Time: 10 Minutes

Sulfur per Min: 180,  Sulfur per Wood: 6,  Check-in Time: 5 Minutes

Sulfur per Min: 180, Sulfur per Wood: 6, Check-in Time: 5 Minutes

Large Furnace - Standard Efficient Stacks

For those looking for an overall balance of all things at a high efficiency, a typical 1000 word well stacked furnace can do the tricky. It does mean checking your furnaces every 30 minutes, but that's far more reasonable than every 5 to 10. With day cycles lasting 45 minutes, you can manage your furnaces every night cycle.

Metal Ore - 2804 Metal Ore + 1000 Wood

  • Frags per Min: 84
  • Frags per Wood: 2.8
  • Check-in Time: 33 Minutes

Fill your furnace with 1000 wood, 13 stacks of 200+ metal ore, 1 stack of 138 metal ore, and 1 stack of 66 metal ore. This will take 33 minutes to cook and yield 2804 metal fragments. To make this a little easier to do, fill 13 stacks of 1000 metal. Grab another stack of 1000 metal, cut it in half to 500 with middle mouse drag, cut a third off with shift+middle mouse drag to 166, do it one more time so you have 1 stack of 111 and 1 stack of 55. Put these 2 final stacks into the furnace so you have 13 stacks of 1000, 1 stack of 111, and 1 stack of 55. You can run 5 batches of 1000 wood replacing the stacks of 111 and 55 each time making this fairly convenient while still very efficient.

Sulfur Ore - 5106 Sulfur Ore + 1000 Wood

  • Sulfur per Min: 153
  • Sulfur per Wood: 5.1
  • Check-in Time: 33 Minutes

Fill your furnace with 1000 wood, 10 stacks of 400+ sulfur ore, and then 1 stack of each of the following: 389, 298, 215, 138, 66. You can more easily enter the stack amounts by right clicking the stack number bar to manually enter a number. If you get annoyed making those specifically numbered stacks, grab 1 stack of 1000 sulfur ore. Pull out a stack close to but not over 389, repeat for 298, 215, 138, and 66. As easier to remember set of numbers is 350, 300, 200, 100, 50.

Smelting Screenshots - 1k Wood

Frags per Min: 90,  Frags per Wood: 3,  Check-in Time: 10 Minutes

Frags per Min: 90, Frags per Wood: 3, Check-in Time: 10 Minutes

Sulfur per Min: 153,  Sulfur per Wood: 5.1,  Check-in Time: 33 Minutes

Sulfur per Min: 153, Sulfur per Wood: 5.1, Check-in Time: 33 Minutes

Oil Refinery - Efficient Stacks

Though not quite as complicated, smelting crude oil in the oil refinery is a bit different in that 1 crude generates 3 low grade fuel.

  • Low Grade Fuel per Min: 31
  • Low Grade Fuel per Wood: 1
  • Check-in Time: 33 Minutes

Place 1000 wood in your oil refinery along with 344 crude oil broken into stacks of 155, 139, and 55.

Crude Smelting

Low Grade Fuel per Min: 31, Low Grade Fuel per Wood: 1, Check-in Time: 33 Minutes

Low Grade Fuel per Min: 31, Low Grade Fuel per Wood: 1, Check-in Time: 33 Minutes

Small Furnace - Efficient Stacks

Small furnaces are far more straightforward than large. At 6 slots each they're just too small to create many options. You need at least 3 slots for the output, charcoal, and wood, leaving 3 for ore.

Metal Ore - 600 Metal Ore + 1000 Wood

Place 1000 wood and 3 stacks of 200+ metal ore into your furnace.

  • Frags per Min: 18
  • Frags per Wood: 0.6
  • Check-in Time: 33 Minutes

Sulfur Ore - 1000 Sulfur Ore + 835 Wood

Place 835 wood and 3 stacks of 333+ sulfur ore into your furnace.

  • Sulfur per Min: 36
  • Sulfur per Wood: 1.2
  • Check-in Time: 28 Minutes

The only notable thing to mention is that due to how sulfur cooks, you actually don't need to put a full stack of 1000 wood. It will create a full 1000 stack of sulfur with just 835 wood. It won't be a problem if you drop 1000 wood, and 3 stacks of 1000 sufur ore as the furnace will fill up and turn off. However, if you split 1000 sulfur ore into 3 stacks be sure to use 835 wood otherwise it will burn through a full stack of 1000, wasting 165.

High Quality Metal Ore - 100 High Quality Ore + 340 Wood

Place 340 wood into your furnace along with 100 high quality metal ore split into thirds.

  • HQM per Min: 8.9
  • HQM per Wood: 0.3
  • Check-in Time: 11 Minutes

High Quality Metal Ore - 216 High Quality Ore + 1000 Wood

Given how little high quality ore you get and how much it costs to smelt it, the efficiency hardly matters. This is an alternate option that's less wood efficient but outputs more than double the previous setup. Place 1000 wood into your furnace along with stacks of 100, 83, and 34 high quality metal ore.

  • HQM per Min: 6.5
  • HQM per Wood: 0.22
  • Check-in Time: 33 Minutes

Small Furnace Smelting

Frags per Min: 18,  Frags per Wood: 0.6,  Check-in Time: 33 Minutes

Frags per Min: 18, Frags per Wood: 0.6, Check-in Time: 33 Minutes

Sulfur per Min: 36,  Sulfur per Wood: 1.2,  Check-in Time: 28 Minutes

Sulfur per Min: 36, Sulfur per Wood: 1.2, Check-in Time: 28 Minutes

HQM per Min: 8.9,  HQM per Wood: 0.3,  Check-in Time: 11 Minutes

HQM per Min: 8.9, HQM per Wood: 0.3, Check-in Time: 11 Minutes

HQM per Min: 6.5,  HQM per Wood: 0.22,  Check-in Time: 33 Minutes

HQM per Min: 6.5, HQM per Wood: 0.22, Check-in Time: 33 Minutes

Final Thoughts

If you're a solo or small group smelting only with small furnaces, there isn't many places where you can go wrong. Simply load the things up and let them do their thing. However, even solos can create large furnace bases just for a standard 2x2 so knowing how to make the most use out of them is meaningful. There is a huge difference in time and resource efficiency for how you smelt and knowing your options allows you to better make use of your time.

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