Sandustry Thermal Buffer and Burner Belt

The Thermal Buffer is the building that turns heat into a utility, the same way a tank turns Water into a utility. Official research text: it stores and distributes heat for nearby machines. Community Early Access write-ups put a heat segment on the slag conveyor so residue becomes Burnt Slag on the way to the Kinetic Slag Press — that segment is this buffer plus, often, a Burner Belt. If you are still walking the line with a Flamethrower, this page is the unlock you felt missing.

What the buffer actually does

Heat in Sandustry is a pixel state, not a hidden watt. Lava, fire, embers, and hot machines raise temperature. Cold structures, Snow, and Cryoblaster shots lower it. Official beginner language: hot thermal structures refine solid → liquid → gas; cold thermal structures run the ladder backward. The Thermal Buffer sits in the middle as a battery of temperature so a Smelter, Pyro Dispenser, or Burner Belt can stay hot without a lava river through the mall.

It does not generate heat from nothing. You still need a source: adjacent Lava, a fire box, or another hot machine. Think of it as a capacitor, not a reactor.

Lava-powered factory footage — heat as a first-class input

Research and neighbors

Node	Catalogue cost (launch table)	Job
Thermal Buffer	~1000 Gold	Store / share heat
Burner Belt	~500 Gold	Ignite flammables when the Buffer feeds it
Pyro Dispenser	~2000 Gold	Flame burst every ~3 s, Buffer-fueled
Smelter	~3000 Gold	Melt elements on top; Buffer or Lava fuel

Factory Level can hide these nodes. Hotfix 0.5.3 shows the blocking objective. Costs follow the official research table until a later Steam note moves them.

Place the Buffer adjacent to the machine that should stay hot. Diagonal kisses are less reliable than a shared edge. Do not bury the Buffer under a full sand pile — you need to see whether it is actually charged.

The slag auto-burn (why you came here)

Starter Factory and Slag Processing already tell you: burn before the press. Manual Flamethrower works. The Buffer upgrade is:

Shaker slag exit → long conveyor → Thermal Buffer + Burner Belt segment → Burnt Slag → Kinetic Slag Press → Collector

Rules that keep it honest:

• The belt must be long enough for ignition to finish before the press tile. Short belts deliver raw Slag and jam the press.
• Gold Collectors stay under the shaker and press, not under the fire segment (Collectors and Lights).
• Flowers and Moss stay on another floor. Embers ignite botanical rows (Flowers and Planters).
• Filters reject Wet Sand from the burn lane (Filters).

If the Buffer is cold, the Burner Belt is just a conveyor. Charge it from Lava via a Scoria / Cinder heat import, or from a dedicated firebox you control.

Heat versus cold (do not mix the rooms)

You will also use cold for Florinol condensation and for Ice tricks. Official rule again: heat climbs the state ladder, cold descends it. Build two closets:

• Hot closet: Buffer, Burner Belt, Smelter, lava import.
• Cold closet: Condenser, Snow, Cryoblaster, Florin → Florinol.

A shared wall is fine. A shared tile is how you invent Steam in the battery room and Ice on the slag belt.

Smelter and Pyro Dispenser

Smelter wants elements on top and heat from the Buffer or Lava. Use it for metal / copper lines that later fill Power Bricks — not as a second Shaker. Pyro Dispenser is a timed flamethrower turret for clearing flammable junk or lighting a residue pit you cannot belt. Both are hungry neighbors; one Buffer can starve if you hang three machines on a single charge. Start with one consumer per Buffer until you watch the heat hold.

Safety

• Queued buildings block Water (demo hotfix habit that still matters). Do not sketch a Buffer in a flood channel.
• Ctrl-replace (Hotfix 8) lets you swap a dead belt tile for a Burner Belt without deleting the line (Demo Patches).
• Hard Mode still lets hover clip rules differ. The Buffer does not care; your body does (Movement and Hover).

When to buy it

Buy Thermal Buffer after Logistics 1 and Tools 1 (Flamethrower), once walking the slag belt is the boring part of every session. Buy it before you start the Energy heat cell — that cell is the same building with a different feedstock (Dry Amethelis instead of Slag).

Related

• Slag Processing — Why Burnt Slag exists.
• How to Get Energy — Heat and cold as a recipe, not a belt.
• Lava, Scoria, and Cinder — How to move a heat source.
• Buildings Hub — The rest of the machine list.

Heat is a belt. Buffer it, or keep walking.