How to Move Lava in Sandustry

Every other fluid in Sandustry moves the obvious way: a Pump at one end, Pipes in between, a Liquid Vent at the other. The official Beginner’s Guide names the exception in the same breath as the rule — Official“You can move any Fluid besides lava”.

So Lava does not travel as Lava. It travels as a rock.

The cycle

Four steps, each with a catch worth knowing before you build for it.

1. Freeze it — Cryoblaster, tier 2, 1,000 Gold

The Cryoblaster is the game’s snow gun, and it never runs dry: it will generate Snow indefinitely, which is what makes this loop repeatable rather than a one-off trick. Snow landing on Lava turns that Lava into Scoria.

Scoria exists for no other reason. It is not something you find while digging — the only way any Scoria comes into the world is by freezing Lava, which means finding a pool of it in the first place is unavoidable.

2. Dig it — 10 HP, any digging tool

Scoria takes 10 HP to break. That puts it above Dirt at 4 and Stone at 8, and below Redsoil at 20 — tougher than the ground around it, but not gated behind an unlock. Even the Shovel works.

Breaking it drops Cinder.

3. Move the Cinder

Cinder is an ordinary solid: density 50, and launchable. It rides Conveyor Belts and Launchers, and the Grabber carries it.

Note what it shares that number with: Residue and Burnt Residue are also 50. On a line carrying any of those together, nothing settles below anything else, so you cannot let the pile sort itself and skim Cinder off the bottom. A Filter set to allow Cinder still works — it sorts by name — but only if the Cinder actually reaches it. Feed that stretch as a thin, well-mixed layer rather than a deep pile, or run the Cinder on its own belt and skip the problem.

4. Light it — the Flamethrower, and nothing else

This is the step that catches people. Ambient heat will not do it; Cinder needs a direct flame on it to melt back into Lava. That means the Flamethrower — tier 2, 400 Gold, and cheaper than the Cryoblaster you already needed to start the cycle.

Where Lava comes from in the first place

Lava occurs naturally, deep underground, in the Lava Cave. Worlds are built from a seed, so no coordinates will find it for you, but the cave is a fixture of every world rather than a lucky roll.

Three things Lava does once you have placed it

It ignites whatever passes over it. Lava can be held inside a Filter, and anything crossing that Filter catches fire if it is capable of burning. That is the no-moving-parts auto-burner behind the slag processing setup — and the official page names Flower auto-burners in the same breath, which is the cheap way to harvest a flower bed.

The official method for pinning it in place is worth spelling out, because it sounds backwards: set a Filter to allow Cinder only, put a solid block underneath it, fill it with Cinders, and light them. The Cinders become Lava with nowhere to go, and now you have a lava cell exactly where you wanted one. Before v0.6.0, Residue run along the belt over the top came off as Burnt Residue. That update’s Filter rule does not allow Residue in a Cinder-only Filter, so test this on a short belt first; the slag processing page has the full build.

It makes Steam without being consumed. Drop Water onto Lava and the Water flashes to Steam while the Lava stays exactly as it was — the pool does not shrink.

That second property is the one worth building around. A lava cell with water dripping onto it is a Steam source that never runs down, and Steam is what the Steam Turbine and the heat chain run on. The Cryoblaster closes the loop from the other side: Snow becomes Water, so the same tool that starts the lava cycle also feeds a renewable water supply — though the snow has to be heated and rained back down first. A captured Lumling is the other renewable route, and it skips the conversion entirely; the critters page compares the two.

It eats some terrain. Since v0.5.6, Lava destroys Fluxite, Redsoil and Strataform. A lava cell built against a Redsoil wall will not stay sealed for long, and the same behaviour clears a pocket of those three without anyone digging it. The same patch changed what a cold Thermal Buffer does to Lava touching it: the Lava turns back into Cinder instead of being used up, which gets you Cinder without the freeze-and-dig steps. The heat page covers the buffer side.

The numbers

Material	Density	HP	Comes from	Turns into
Lava	200	—	Cinder + fire	Scoria (with Snow)
Scoria	—	10	Freezing Lava	Cinder (when broken)
Cinder	50	—	Breaking Scoria	Lava (Flamethrower)

Lava’s density went from 75 to 200 in v0.5.6. At 200 it is heavier than Water at 100 and Residue and Cinder at 50, so in a mixed pool it sinks to the bottom. It now ties with Copper, Aurixite and Sunsand; only Gold, at 300, sinks below it. The wiki’s Lava page still shows the old 75, because nobody has edited it since the patch. The number here comes from the developer’s patch note.

Related

• Sandustry Slag and Residue Processing — the Lava auto-burner, in full
• Sandustry Heat and the Thermal Buffer — where the Steam goes
• Sandustry Filters Explained — why density decides what a Filter ever sees
• How to Move Water in Sandustry — the fluid that does go down a pipe