Smelter Upgrades

Your workbench and forge get better when you build things next to them. Your charcoal kiln, smelter and blast furnace never did — they are exactly as slow on day 400 as they were on day 1, they hold a queue you cannot see, they happily accept the wrong ore, and they must be hand-fed forever.

This mod fixes all four, and gives your spare Surtling Cores something to do.

Upgrade pieces

Build these near a kiln or smelter and it gets better. The station's level and active bonuses show in its tooltip, and a spark stream connects each upgrade to the station it feeds — the same way a chopping block connects to a workbench.

Piece	Station	Effect	Cost	Built at
Kiln Vents	Charcoal kiln	+25% speed, +15 wood	5 Bronze, 10 Copper	Workbench
Wood Rack	Charcoal kiln	+15 wood	15 Fine Wood, 5 Iron	Workbench
Smelter Bellows	Smelter	+25% speed, +6 ore	10 Iron, 5 Troll Hide, 2 Chain	Forge
Ore Hopper	Smelter	+10 ore, +20 coal capacity	10 Silver, 10 Obsidian	Forge
Furnace Tuyeres	Blast furnace	+25% speed, one coal a bar instead of two, +6 ore	10 Black Metal, 10 Iron, 2 Chain	Black forge
Charging Ramp	Blast furnace	+10 ore, +20 fuel capacity	20 Fine Wood, 8 Iron, 5 Black Metal	Black forge
Stoker's Chest	—	Feeds nearby stations	10 Black Metal, 10 Linen Thread, 5 Iron	Forge

Every upgrade raises its station's capacity as well as doing its own job. Build both kiln pieces and the kiln goes from 25 wood to 55. Build both smelter pieces and it holds 26 ore and 40 coal. Build both blast furnace pieces and it holds 26 ore and 40 coal — and burns half the coal getting through it.

Only one of each type counts per station, so you cannot ring a smelter with five bellows.

Recipes are deliberately spread across biomes — Black Forest through Plains — so upgrades are earned rather than free on your first day.

Lock a station to one input

Press N while looking at a smelter, kiln or blast furnace to cycle what it accepts: unlocked → each valid input in turn → unlocked. A smelter can be pinned to Copper Ore, a kiln to Fine Wood.

A locked station refuses everything else, and its item menu only offers what it wants — no more dropping tin into the iron smelter, or feeding your good wood to the charcoal pile.

You can see the lock from across the base. The ore's own icon floats at the spot you feed the station, so a row of smelters tells you what each one is set to without walking up and hovering every one. ShowLockIcon, LockIconSize, LockIconHeight and LockIconRange tune it or turn it off.

The key is rebindable in the game's own controls menu. It was G until the Deep North update took that key for the radial action wheel — if you had already rebound it yourself, your binding is kept.

Surtling Cores as fuel

Smelters and blast furnaces accept Surtling Cores as a high-grade fuel. One core is worth 4 coal and doubles smelting speed while it burns. The fuel tooltip shows how much core fire is left.

Cores also buy portals and smelters, so burning them is a real trade-off rather than free power.

Fuel is one pool, so once cores and coal are mixed the boost runs until the core fuel is spent rather than tracking individual cores.

See the queue

Hovering a station draws its input queue as item icons under the crosshair, grouped as icon x4, so you can tell what is actually in there without emptying it.

Stoker's Chest

A chest that quietly tops up every kiln, smelter and blast furnace in range with fuel and ore from its own inventory. It respects the ore lock and never overfills, and its Stations setting decides which stations it serves.

Configuration

Everything is configurable in BepInEx/config/zl.smelterupgrades.cfg — every bonus, every range, the core fuel value and speed multiplier, the feeding interval, and the hotkey.

Each upgrade piece also has a ModelPrefab setting if you would rather it wore a different model, and UseVanillaShader draws the mod's models with Valheim's own shader so they weather, wet and take snow like the rest of the world.

There is also a FuelEfficiencyBonus per piece. The game stores coal-per-bar as a whole number, so this rounds hard: on a station burning 2 coal a bar — the smelter and the blast furnace both do — anything up to 0.25 rounds straight back to 2, and only past that does it drop to 1. That is why the tuyères ship at 0.30, where it lands, and the bellows at 0.25, where it is deliberately inert until you raise it. The tooltip only ever reports a saving that actually happened.

Updating keeps your config. When a shipped default changes, a setting only moves if you had left it at the old default — anything you tuned yourself stays exactly as you set it.

Turn on DebugLogBaseStats to log each station's untouched vanilla stats, which is the honest way to tune the numbers for your own balance.

Multiplayer

Every player on the server needs this mod installed, and so does a dedicated server. The custom pieces cannot spawn for anyone who does not have it.

Installation

Use a mod manager, or install Jotunn and drop SmelterUpgrades.dll into BepInEx/plugins.

Uninstalling

Remove any pieces this mod added before uninstalling. Valheim deletes prefabs it no longer recognises, so a Stoker's Chest left standing will vanish and take its contents with it.

Contact

Got an idea? I'd love to hear it — new upgrades, feature requests, balance thoughts, or just to say it's working for you. Find me on Instagram: @lg_9d