I use ferric chloride for PCB etching when I have to fabricate pcb circuits at home. But lately I was looking for what other PCB etching solution could be used. Ferric chloride is good but it takes time so I came to use using hydrocloric acid and hydrogen peroxide. For homemade PCB etching, below are five various chemical etching solutions to remove the PCB copper board layer and create circuit traces.
1. Ferric Chloride (FeCl₃)
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Pros: Most commonly used, effective, and widely available.
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Cons: Stains skin and surfaces, generates hazardous waste.
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Mixing Ratio: Use a 1:2 ratio of Ferric Chloride to water.
2. Muriatic Acid(Hydrochloric Acid (HCl)) + Hydrogen Peroxide (H₂O₂)
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Mixing Ratio: 1 part HCl (30-40%) + 2 parts H₂O₂ (3%) + 3 parts water.
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Pros: Works fast, reusable to some extent.
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Cons: Produces toxic fumes (use in a ventilated area), dangerous to handle.
3. Copper (II) Sulfate (CuSO₄) + Table Salt (NaCl)
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Mixing Ratio: 40g CuSO₄ + 40g NaCl in 100ml water.
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Pros: Environmentally friendlier, cheaper.
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Cons: Slower etching process.
4. Sodium Persulfate (Na₂S₂O₈)
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Pros: Clear solution, allows easy monitoring of etching.
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Cons: Requires heating (~40-50°C) for better efficiency.
5. Ammonium Persulfate (NH₄)₂S₂O₈
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Pros: Produces finer traces than Ferric Chloride.
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Cons: More expensive, degrades over time.
Alternative Eco-Friendly Method
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Vinegar (Acetic Acid) + Hydrogen Peroxide + Salt
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Mixing Ratio: Equal parts of vinegar and H₂O₂, add salt until it dissolves.
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Pros: Safer, can be disposed of more easily.
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Cons: Very slow process.
What is muriatic acid?
Muriatic acid is a common name for hydrochloric acid (HCl), typically in a diluted form (around 30-35% concentration). It is a strong, highly corrosive acid used for cleaning, etching, and industrial applications.
Common Uses of Muriatic Acid
- PCB Etching – Combined with hydrogen peroxide (H₂O₂) to create a copper etching solution.
- Metal Cleaning & Rust Removal – Dissolves rust and oxidation from metals.
- Concrete Cleaning – Removes stains and mineral deposits from bricks and concrete.
- Pool pH Adjustment – Used to lower pH levels in swimming pools.
- Household Cleaning – Removes tough stains, but requires extreme caution.
Chemical Properties
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Formula: HCl
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Appearance: Clear or slightly yellowish liquid
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pH: Very low (strong acid)
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Fumes: Releases strong, irritating fumes
Actually, any HCl (hydrochloric acid) can be used for etching printed circuit board at home, but the concentration matters. The most commonly used type is muriatic acid (30-35% HCl), which is easily available and works well when mixed with hydrogen peroxide (H₂O₂).
How to Use HCl for PCB Etching?
1. Materials Needed
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Hydrochloric Acid (HCl, 30-35%) (Muriatic Acid)
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Hydrogen Peroxide (H₂O₂, 3-6%)
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Plastic or glass container (DO NOT use metal)
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Gloves, goggles, and a mask
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Plastic tongs or sticks to handle PCB
2. Mixing the Etching Solution
✅ Mix in this order (important!):
1 part HCl + 2 parts H₂O₂ + 3 parts water
(Example: 50ml HCl + 100ml H₂O₂ + 150ml water)
⚠ Safety Tip:
👉 Always add HCl to water, never the other way around to prevent violent reactions.
👉 Work in a well-ventilated area (produces strong fumes).
3. Etching Process
- Place the PCB (with the copper side facing up) in the solution.
- Gently agitate the container to speed up the reaction.
- Copper will dissolve in 5-15 minutes, depending on concentration.
- Once etching is complete, remove the PCB and rinse it thoroughly with water and baking soda to neutralize the acid.
In the guide PCB design with Proteus Ares the PCB was made using this PCB etching solution. And in the guide,
