- Core concept: Use Filters to separate materials based on physical state.
- The trick: Wet sand acts as a solid, while water acts as a liquid.
- Key component: Standard Conveyor Filters can distinguish between wet solids and fluids.
- Common use: Essential for automated mud production and water-based processing chains.
- Pro tip: Ensure your filter output has a dedicated collection belt to prevent backups.
Understanding Wet Sand vs. Water Physics
In Sandustry, the falling-sand engine treats "wet" materials differently from pure liquids. When a dry powder like sand touches water, it often converts into a "wet" variant (e.g., wet sand or mud). Crucially, the game classifies these wet variants as solid objects that can be carried by conveyors, whereas water remains a liquid that flows over terrain and requires pipes.
This physical distinction is the foundation of filtering. You are not just separating by material name, but by interaction category. A standard filter set to accept wet sand will grab the solid clumps falling onto it, while allowing the liquid water to flow past or into a separate drainage system.
Wet Sand Properties
- Type: Solid Particle
- Transport: Conveyors, Launchers
- Interaction: Can be crushed, heated, or stored
- Filter Logic: Detected as a specific resource ID
Water Properties
- Type: Liquid
- Transport: Pipes, Pumps, Open Terrain
- Interaction: Evaporates, turns sand wet, flows downhill
- Filter Logic: Ignored by solid-specific filters
Be careful when mixing water and loose dry sand. If water touches a pile of dry sand on a conveyor, it may convert the entire stack into wet sand instantly, potentially clogging a line designed for dry materials.
Building the Wet Sand Filter
To create a machine that lets wet sand through but stops water, you need to leverage the Filter building. This building acts as a gatekeeper, only allowing specific materials to pass from an input belt to an output belt.
Video Highlights:
- Visualizing the difference between liquid flow and solid transport.
- Setting up a basic input hopper for mixed materials.
- Configuring the Filter to target "Wet Sand" specifically.
- Using a drainage gap or pipe to catch the excess water.
Set Up Mixed Input
Direct a conveyor belt carrying a mix of water and wet sand into the Filter's input slot. This often comes from a mining operation where you have breached a water pocket or a processing chamber where water is introduced to sand.
Configure the Filter
Access the Filter's menu. Select Wet Sand (or the specific wet material you are targeting) as the Allowed material. Ensure the filter is set to "Block All Others" or specifically configured to ignore liquids if the game uses a whitelist system.
Create a Water Drain
Position the Filter so that water flows off the belt or into a gap. Since the Filter grabs the solid wet sand, the water should remain on the belt or flow underneath/around. You can place a Pipe or Pump intake directly below the filter to catch the water.
Connect Output Logistics
Attach an output conveyor to the Filter. This belt will now carry only the purified wet sand to your next processing station (e.g., a furnace, crusher, or storage), free of water contamination.
If your factory uses Launchers, you can set up a launcher chain that only accepts wet sand. Water cannot be loaded into standard launchers, providing a passive "filtering" method if you are moving materials vertically.
Layout Designs for Separation
Different factory layouts require different filtering strategies. While the Filter machine is the most precise method, you can also use gravity and terrain physics to separate wet sand from water.
| Method | Complexity | Throughput | Best Use Case |
|---|---|---|---|
| Filter Machine | Low | High | Standard factory lines, precise sorting |
| Gravity Drain | Medium | Medium | Sloped terrain, early-game sorting |
| Launcher Transfer | Low | Low | Moving resources between elevations |
| Pipe Siphon | High | High | Extracting water from a wet sand mix |
You can dig a trench under your conveyor line. If the belt has gaps (or is a mesh belt), water will leak out and fall into the trench, while wet sand stays on top. You can then line the trench with pipes to transport the water away.
Advanced Water Management
Once you have successfully separated your wet sand, you need to manage the displaced water. Water is a valuable resource for Aura Extraction, Cooling, and Farming, so do not simply delete it.
Water Collection Checklist:
- Place Pumps at the lowest point of your filter drainage area.
- Connect pumps to a dedicated Water Pipe network.
- Route water to Storage Tanks or directly to Hydroponics.
- Ensure no water is flooding back into your solid material logistics.
| Water Destination | Purpose | Connection Type |
|---|---|---|
| Processing Plants | Irrigation, Reaction mixing | Pipe Output |
| Cooling Systems | Preventing machine overheating | Direct Pipe Link |
| Storage | Buffering excess water | Tank Input |
| Disposal | Removing flood water | Edge of Map |
Troubleshooting Common Issues
Even with a solid plan, physics glitches or blockages can occur. Here are solutions to the most common problems players face when trying to let wet sand through but not water.
Common Problems & Fixes:
| Problem | Cause | Solution |
|---|---|---|
| Water backing up | Pump is too slow or output is blocked. | Upgrade pumps or widen the output pipe. |
| Wet Sand disappearing | Filter is set to wrong material or is full. | Check Filter settings and ensure output belt is moving. |
| Sand turning wet too early | Water leaking into dry input line. | Use Pipes to contain water before the mixing point. |
| Filter not grabbing items | Belt speed is too high. | Slow down input belt or use multiple filters in parallel. |
In hot biomes or near machinery, water can evaporate. If your filter relies on gravity drainage, ensure the water reaches a pump or covered channel before it evaporates, leaving you with a dry sand blockage instead.
Production Chain Integration
Integrating this filter into a larger production line requires planning. Wet sand is often an intermediate product used to create Mud, Clay, or specialized Compounds.
Example Production Chain:
- Mining: Sand + Water (Mixed) -> Filter (Wet Sand separated)
- Logistics: Wet Sand -> Conveyor -> Crusher/Grinder
- Processing: Wet Sand -> Mud -> Construction Materials or Alchemy
Q: Can I use a Splitter instead of a Filter?
No. A Splitter divides the input stream evenly regardless of material type. It cannot distinguish between water and wet sand. You must use a Filter building or a physics-based gravity gap.
Q: Why is my water turning into steam?
Your filter or drainage system is likely too close to a heat source (like a furnace or reactor). Water turns to steam at high temperatures, which can clog pipes. Insulate your water logistics from heat-generating machinery.
Q: How do I automate the removal of water?
Use a **Pump** placed directly in the pool where water collects after the filter. Connect the Pump to a pipe network leading to a storage tank or usage point. The Pump will automatically pull liquid water into the pipe system.
Q: Does this work for other wet materials?
Yes. The logic applies to any 'wet' variant in the game (e.g., Wet Dirt, Wet Soil). As long as the game classifies the wet material as a solid and the fluid as a liquid, the Filter will separate them effectively.