Quick answer: Find Lava in the deep Lava Cave, freeze it into Scoria with Snow from the Cryoblaster, break the Scoria into Cinder, carry the Cinder as a solid, and ignite it only at the destination to turn it back into Lava.
The Lava transport cycle
Lava is useful because it can ignite suitable pixels that pass over it, but moving the liquid itself through a factory is awkward. Sandustry provides a solid-material transport cycle:
Lava + Snow → Scoria → break it → Cinder + Fire → Lava
Cinder is the portable stage. It can travel by Grabber, Conveyor Belt, or Launcher, which lets you use ordinary logistics for most of the route. The dangerous liquid exists only at the source and at the final burner.
This one cycle also explains several related searches. Scoria is the frozen intermediate, Cinder is the transport material, and a “Slag burner” is an outdated player description for the current Lava trap that turns passing Residue into Burnt Residue—not the verified name of a separate building.
What to unlock first
The current official Research table lists these relevant unlocks:
| Research | Current cost | Why it matters |
|---|---|---|
| Filter | 250 | Unlocks the Filter used to hold Cinder and trapped Lava |
| Flamethrower | 400 | Unlocks the tool used to ignite Cinder |
| Cryoblaster | 1,000 | Unlocks the tool used to create Snow and freeze Lava |
Research costs can change during Early Access. Confirm the in-game table if a value differs after an update.
Prepare a weapon to break Scoria, a safe Cinder collection pocket, and a solid-material route before freezing a large area. Cinder that reaches fire too early turns back into Lava before it reaches the destination.
Move Lava from the cave to the factory
- Expose a controlled edge of the Lava source. Work from a position where newly frozen material cannot trap the player or block the exit.
- Apply Snow with the Cryoblaster. Snow touching Lava solidifies it into Scoria.
- Break the Scoria. Destroying it produces Cinder that can be picked up or placed on logistics.
- Collect the Cinder away from fire. Keep Flamethrowers and open flames out of the transport path. The current Cinder page says passive environmental heat alone does not melt Cinder.
- Move Cinder as a normal solid. Use the Automation Guide to keep the belt or Launcher route visible and give it a clear destination.
- Ignite only inside the final containment. Do not create Lava until the Filter trap is closed and ready.
Transport a small batch first. If the destination cannot hold it, you want a few Cinders to recover—not a full belt converting back into Lava.
Build a Filter Lava trap
The official Lava and Filter pages describe a compact containment method:
- Place a solid Block directly below a Filter.
- Configure the Filter to allow only Cinder through.
- Feed Cinder across the Filter so it enters but cannot fall out through the blocked bottom.
- Stop the input before the Filter overfills or the belt backs up.
- Ignite the trapped Cinder with the Flamethrower.
- Confirm the resulting Lava remains inside the Filter before connecting production.
The Filter is useful here because it is permeable to liquid while its sealed lower exit creates a small holding space. The surrounding layout still needs to prevent unintended liquid flow, and the ignition step should happen only after the Cinder route is shut off.
Turn the trap into a Residue burner
When the Filter is filled with trapped Lava, move Residue across its conveyor surface. Lava touching suitable pixels above the Filter ignites them, converting Residue into Burnt Residue for the later refining chain.
Build the burner after the ordinary Wet Sand line works. The Processing Plant Guide covers how that line creates Residue and keeps its Gold output separate. Adding a burner cannot fix a Shaker that is already blocked upstream.
A stable burner needs three independent capacities:
- enough trapped Lava to contact the passing material;
- a controlled Residue feed that does not bury the Filter;
- an open Burnt Residue destination so the output cannot stop the belt.
Troubleshoot Lava and burner failures
Cinder turns into Lava on the route
Remove nearby fire and separate the Cinder belt from the source pool. Cinder is meant to remain solid until the destination. Clear the route from the far end before releasing another batch.
Cinder passes through the Filter
Check that the Filter is configured for Cinder and that a solid Block closes the space directly below it. If the lower space is open, the selected material behaves exactly as configured and falls through.
The burner works briefly, then stops
Inspect the Burnt Residue destination first. A full output causes material to remain above the Lava trap and blocks new Residue from reaching the ignition point. Reduce the input, clear the end, and restart with a small flow.
Lava becomes Scoria inside the factory
Snow from the Cryoblaster freezes Lava. Keep Snow production and Cryoblaster use away from the trap unless you are intentionally recovering the Lava as Cinder.
Water reaches the trap
Water landing on Lava becomes Steam, but the current official Lava page says this does not decrease the amount of Lava. It can still redirect Steam and rain into another part of the factory, so isolate the Water network and follow the containment checks in the Water Guide.
Verified sources
Facts on this page were checked on August 17, 2026 against:
- Official Lava page
- Official Cinder page
- Official Filter page
- Official Research table
- Official Water page
Sandustry is in Early Access. Recheck the official pages after major patches, especially for research costs, material interactions, and Filter behavior.