Furnaces

Tables for the heated furnaces, from the alloy furnaces to the arc furnace’s molten output.

Type	Machines	Schema	Picked by	Rows in HBM
`hbm:blast_furnace`	Blast Furnace	generic	first match in `order`	15
`hbm:difurnace`	Blast Furnace (LEGACY), Nuclear Blast Furnace (LEGACY)	generic	first match in `order`	14
`hbm:combination`	Combination Furnace	own	first match in `order`	53
`hbm:rotary_furnace`	Rotary Furnace	own	first match in `order`	12
`hbm:arc_furnace`	Electric Arc Furnace	own	first row in `order` per input and mode	79

blast_furnace

The airblast Blast Furnace. Generic schema, no extra fields. The furnace uses rows with exactly two item inputs, matched in either slot order and with their counts, and at most two item outputs. duration is in ticks; power is not used (the furnace burns fuel and makes flue gas).

{
  "type": "hbm:blast_furnace",
  "name": "blast.firebrick",
  "input_items": [
    { "ingredient": "#c:dusts/aluminium" },
    { "ingredient": "minecraft:clay_ball", "count": 7 }
  ],
  "output_items": [{ "id": "hbm:ingot_firebrick", "count": 8 }],
  "duration": 800,
  "order": 13
}

The first matching row in order wins.

difurnace

The legacy fuel-fired alloy furnace (1.7’s BlastFurnaceRecipes), a separate machine from the Blast Furnace above. Generic schema, no extra fields. Like the blast furnace it uses rows with exactly two item inputs, in either slot order, with their counts, and the first output item. Its processing time is fixed by the machine, so duration does not change it. The first matching row in order wins.

{
  "type": "hbm:difurnace",
  "name": "difurnace.steelFromCoke",
  "input_items": [
    {
      "type": "hbm:any_of",
      "of": [
        { "ingredient": "#c:ingots/iron" },
        { "ingredient": "#c:plates/iron" },
        { "ingredient": "#c:gems/iron" },
        { "ingredient": "#c:dusts/iron" }
      ]
    },
    { "ingredient": "#c:cokes" }
  ],
  "output_items": ["hbm:ingot_steel"],
  "duration": 400,
  "order": 1
}

Notes:

1.7’s “any form of this material” ingredient is hbm:any_of; its gasoline canister is {"type": "hbm:fluid_item", "item": "hbm:canister_full", "fluid": "hbm:gasoline"} (see difurnace/napalm.json).
The furnace’s fuels are not recipes. They are the item data map hbm:difurnace_fuel.
The row named difurnace.meteorSword is hidden from recipe viewers, as 1.7 hid it.

combination

Field	Type	Required	Default	Meaning
`input`	ingredient (or the Stirling form)	yes		What is heated.
`item_output`	item stack	no	none	Item product.
`fluid_output`	fluid stack	no	none	Fluid product.
`order`	int	no	after HBM’s	The first matching row in `order` wins.

{
  "type": "hbm:combination",
  "input": { "ingredient": "hbm:briquette_coal" },
  "item_output": "hbm:coke_coal",
  "fluid_output": { "type": "hbm:coalcreosote", "amount": 150 },
  "order": 2
}

Both outputs are optional, but the furnace refuses a row without an item output (HBM keeps 1.7’s sodium-dust row that way).

rotary_furnace

Field	Type	Required	Default	Meaning
`inputs`	list of up to 3 ingredients	no	none	Unordered; counts are required amounts.
`fluid`	fluid stack	no	none	Fluid the tank must hold (matched by type).
`output`	material stack	yes		Molten metal produced.
`duration`	int	yes		Ticks per operation.
`steam`	int	yes		Steam drawn per tick.
`order`	int	no	after HBM’s	The first matching row in `order` wins.

{
  "type": "hbm:rotary_furnace",
  "fluid": { "type": "hbm:sodium_aluminate", "amount": 150 },
  "output": { "material": "aluminium", "amount": 144 },
  "duration": 100,
  "steam": 400,
  "order": 10
}

Matching as in 1.7: every non-empty input slot must be taken by exactly one ingredient (with enough items), and every ingredient must be taken, in any slot order. A row with fewer ingredients does not match while extra slots hold items.

arc_furnace

The Electric Arc Furnace has a solid mode and a liquid mode. A row can serve either or both.

Field	Type	Required	Default	Meaning
`input`	ingredient	yes		What is melted.
`solid_output`	item output (`"id"` or `{"id", "count"}`)	one of the two outputs	none	Result in solid mode.
`molten_outputs`	list of material stacks	one of the two outputs	none	Result in liquid mode.
`order`	int	no	after HBM’s	Order of the rows.

A row needs solid_output, molten_outputs or both.

{
  "type": "hbm:arc_furnace",
  "input": { "ingredient": "minecraft:flint" },
  "solid_output": { "id": "hbm:nugget_silicon", "count": 4 },
  "molten_outputs": [{ "material": "silicon", "amount": 36 }],
  "order": 1
}

How the list is built. The rows are taken in order. For each mode, the first row for an input claims it; a later row with the same input (same item, or same tag) is dropped for that mode, as 1.7 did. After the rows, three rules in code add more, again only for inputs not yet claimed:

every material shape whose c: tag has an item melts into its material (liquid mode), for every smeltable material;
every item that has a material distribution melts into its materials (liquid mode);
in solid mode, any item with a furnace (smelting) result that is an ingot, ore, plate or storage block (by its c: tags, plus 1.7’s list of vanilla items) gives its furnace result.

The furnace uses the first recipe in this list that matches the item and has an output for the current mode. So a row of yours with a lower order than HBM’s takes an input from HBM’s row, and any row comes before the rules. In liquid mode, scrap items melt into the material they hold, before any row.