OVERVIEW
Chemical etching process for fabricating custom PCBs at home. This complements the CNC milling approach, offering finer trace resolution for more complex designs.
ETCHANT OPTIONS
01
Ferric Chloride (FeCl₃)
Traditional etchant. Fast, reliable, but stains everything brown. Solution darkens as it absorbs copper.
02
Cupric Chloride (CuCl₂)
Regenerable with HCl and oxygen (bubbler). More economical for regular use. Solution turns green.
03
Sodium Persulfate
Clear solution shows etch progress. Less staining. Slower than FeCl₃. Solution turns blue with copper.
PROCESS WORKFLOW
- Design - Create PCB layout in KiCAD or similar
- Transfer - Apply resist pattern (toner transfer or photoresist)
- Etch - Immerse in heated etchant solution with agitation
- Clean - Remove resist, rinse thoroughly
- Drill - Create via and component holes
- Tin - Optional tin plating for solderability
CHEMISTRY
Ferric Chloride: Cu + 2FeCl₃ → CuCl₂ + 2FeCl₂ Cupric Chloride (regenerable): Cu + CuCl₂ → 2CuCl 2CuCl + 2HCl + ½O₂ → 2CuCl₂ + H₂O Sodium Persulfate: Cu + Na₂S₂O₈ → CuSO₄ + Na₂SO₄
SAFETY
Caution: PCB etchants are corrosive and contain heavy metals. Copper-laden waste requires proper disposal - do not pour down drain. Work in ventilated area with appropriate PPE.