Hydrochloric Acid
Hydrochloric Acid is a crafted chemical in Subnautica 2, refined from Deep Shale at the Fabricator. It is the precursor to Polyaniline and several high-tier synthetic materials, gating the advanced electronics and reinforced equipment required for endgame exploration.
Quick Info
How to Craft & Source Materials
Hydrochloric Acid is crafted at the Fabricator from 3 Deep Shale. Deep Shale is mined from large deposits in deep biomes — the same deposits that yield Lithium, Diamond, and Magnetite — so a Prawn Suit Drill Arm is strongly recommended for efficient collection.
Uses & Recipes
Hydrochloric Acid is the precursor to Polyaniline, which is in turn required for the Ion Battery matrix and several advanced electronics recipes. It is one of the highest-tier chemicals in the game and gates the final wave of equipment upgrades.
Polyaniline
Conductive polymer used in advanced electronics and the Ion Battery matrix.
Ion Battery Matrix
Late-game high-capacity power source for vehicles and base modules.
Reinforced Equipment
Late-game hazard protection for deep-biome exploration.
Crafting Calculator
Plan your total Hydrochloric Acid needs across all recipes.
Tips & Strategies
Bring the Prawn Suit Drill Arm
Large Deep Shale deposits can't be harvested by hand. The Prawn Suit Drill Arm cracks them open in seconds and yields 10–15 Deep Shale per deposit, far more efficient than collecting loose ore.
Multi-Resource Farming
Deep Shale deposits share spawns with Lithium, Diamond, and Magnetite. Plan a single deep-biome run that covers all four resources so you don't have to revisit dangerous territory multiple times.
Craft Polyaniline First
Polyaniline is the highest-leverage Hydrochloric Acid sink. It feeds the Ion Battery matrix and most advanced electronics, so prioritize it over reinforced equipment when you first unlock the recipe.
Bring a Cyclops
Deep Shale deposits are deep, dark, and dangerous. A Cyclops parked above the deposit gives you a safe retreat, storage for the haul, and a power cell charger to keep your Prawn Suit running during long mining sessions.
Related Resources
Source Material Locations
Hydrochloric Acid is crafted, but its source material — Deep Shale — is mined from large deposits in deep biomes. Pin Deep Shale farming routes on the interactive map to plan efficient late-game expeditions.
View on Interactive Map →Frequently Asked Questions
How do I craft Hydrochloric Acid?
Hydrochloric Acid is crafted at the Fabricator from 3 Deep Shale. Deep Shale is mined from large deposits in deep biomes, so you'll need a Prawn Suit Drill Arm and a Cyclops or Seamoth with depth upgrades to gather it efficiently.
Where do I find Deep Shale?
Deep Shale is mined from large deposits in the Lost River, Mountains Caves, and other deep biomes below 200m. The Lost River is the most reliable source, but you'll need a Cyclops or Prawn Suit to reach it safely.
What is Hydrochloric Acid used for?
Hydrochloric Acid is used to craft Polyaniline, which in turn gates the Ion Battery matrix and several advanced electronics. It is also required for reinforced equipment used in deep-biome hazard protection.
Do I need a Prawn Suit for Hydrochloric Acid?
Strongly recommended. Large Deep Shale deposits can't be harvested by hand — only the Prawn Suit Drill Arm can crack them open. A Cyclops parked above the deposit provides storage, retreat, and power cell charging for extended mining sessions.
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