Heating furnace

#	Colour	Name	Matches
1		any Refractory bricks	game:refractorybricks-good-tier*
2		Firebox	iiex:furnace-firebox-*-*
3		Fireclay brick slab	game:brickslabs-fire-up-free
4		Fireclay brick slab	game:brickslabs-fire-south-free
5		Iron hatch door	game:cokeovendoor-*-north
6		Heating Furnace Core	iiex:furnace-heatingcore-*-*
7		Charge Door	iiex:furnace-chargedoor-n
8		Heating Hearth	iiex:furnace-heatinghearth-n
9		Reserved space (kept clear)	exlib:structurefiller
10		Empty (air)	game:air

Materials

Block	Cells
any Refractory bricks	68
Firebox	2
Fireclay brick slab	10
Iron hatch door	1
Heating Furnace Core	1
Charge Door	1
Heating Hearth	1

Facings and connectors

• Fireclay brick slab turns with the structure; segment 3 of its code names the face.
• Iron hatch door turns with the structure; segment 3 of its code names the face.
• Charge Door turns with the structure; segment 3 of its code names the face.
• Heating Hearth turns with the structure; segment 3 of its code names the face.

What it does

The heating furnace is the reheat for the forming shop. Stock cools while it is worked, a cold piece will not bite in the rolls, and a vanilla forge tops out at an ingot and cannot hold a slab at all. Anything lying on this hearth climbs back toward rolling heat while the player works at the machines. See Rolling and the forming shop.

It is a reverberatory furnace like the Puddling furnace: the fire burns in a firebox at one end and the flame is drawn across a bridge and over the work.

Building it

1. Place the core first, then ctrl plus shift plus right-click it for the build outline and the shopping list.
2. Lay the ash pit and the firebox at the far end from the core, and set the fire door in front of it. This firebox is two cells, so it holds twice what the puddling furnace's does, though it is charged with one click.
3. Set the heating hearth in the middle: three rows of stock lying in the flame.
4. Set the charge door in front of the hearth.
5. Lay the flue in the core's own column at the near end.
6. Keep laying until the outline reports complete.

The core's side variant fixes the facing and the furnace turns with it. The stack is fixed at the height the layout declares.

The run

1. Charge the firebox with fuel through the fire door and light it.
2. Right-click a hearth cell with a stock piece to lay it in that row. Right-click empty-handed to take it back.
3. Shut the charge door between visits. An open door spills the stack's pull into the room.
4. Work at the mill and the shear while the hearth soaks. A thin piece comes back faster than a thick one, because it is the surface that takes the heat: about 40 seconds for a shingled bar and 58 for a shingled slab.

A loaded centre row blocks both flanks, going in and coming out, so a full hearth unloads centre-first. Whole stacks are never taken: each piece carries its own heat, so pieces go in one at a time.

The hearth soaks at roughly a forge's rate per piece and carries no multiplier of its own. What it is for is that it holds three pieces at once and takes shapes a forge refuses.

Long stock that is not being heated keeps in a Storage Rack, which fills by the length of what is leaned in it rather than by the piece.

What goes wrong

The hearth refuses the piece. Only Shingled Bar, Shingled Slab and the three cast stock pieces have hearth art and are admitted today. Rolled Rod, Beam Blank and Heavy Plate Blank are refused here and by a vanilla forge alike. A piece on one of those routes can still be sheared, because shearing needs no heat, but it cannot be rolled on.

A flank row refuses the piece. The centre row is loaded.

The firebox will not light. The bed is not full. A firebox lights on a full bed, and this one is two cells, so it wants twice the fuel a one-cell firebox does.

The furnace runs cool. The charge door is open. Shut it between visits.

It will not melt anything. It is not meant to. The flame is carried over a bridge to the work, which costs it heat, and the stack is fixed at the two courses the layout declares and cannot be raised, so there is no way to drive it up to iron's melting point. The Crucible furnace is the one furnace here whose chimney the player builds.