Copper & Brass FeCl₃

Chemical Etching Formula
H80 brass with FeCl₃

This page documents the reference wet chemical etching formula for H80 brass using the FeCl₃ system. The recipe below covers a sheet-thickness range of 0.05-0.5 mm and is configured for through etch (double-sided). Every value is drawn from operational process records rather than theoretical calculation, and is provided as a starting point for your own process development.

Formula Summary

The table below summarizes every parameter that defines this etching formula. Values listed as ranges scale with sheet thickness across the supported band.

FeCl₃ Etchant System
36 °Bé Concentration
1.340 Specific Gravity
43 °C Bath Temperature
Through etch (double-sided) Etch Depth Type
0.05-0.5 mm Thickness Range
0.18 mm Typical Thickness
0.12-3.11 m/min Conveyor Speed Range
0.56 m/min Typical Speed
60-600 μm Min Hole Ø Range
100-500 μm Min Line Width Range
9-88 μm Undercut Range
2.83 Etch Factor (EF)
97.8% Typical Yield (97-98.1%)

Why FeCl₃ for H80 brass?

Ferric-chloride-based formulas are the industrial workhorse for ferrous, nickel, and copper-bearing alloys like H80 brass. The Fe³⁺ ion oxidizes the metal surface; where HCl is present it regenerates dissolved species and stabilizes chloride concentration. The result on H80 brass is anisotropic etching with predictable undercut and an easily regenerated spent bath.

Process Window & Bath Control

Bath control for H80 brass in FeCl₃: temperature 43°C, concentration 36 °Bé, specific gravity 1.340. The recipe is tuned for through etch (double-sided). Conveyor speed is the primary throughput control, ranging 0.12-3.11 m/min across the supported thickness range. Check specific gravity each shift with a calibrated hydrometer and correct with fresh make-up or water as needed.

Design Rules & Tolerances

Feature sizes scale with sheet thickness. For this formula the minimum hole diameter ranges 60-600 μm and the minimum line width ranges 100-500 μm across the 0.05-0.5 mm band, following the industry 1.2× (hole) and 1.0× (line) thickness rules. Single-side undercut ranges 9-88 μm, and the etch factor is about 2.83. Size your photomask by subtracting twice the expected undercut from each finished feature dimension.

Design Rule Summary
• Minimum hole diameter range: 60-600 μm
• Minimum line width range: 100-500 μm
• Single-side undercut range: 9-88 μm
• Typical etch factor (EF): 2.83

Yield & Production Economics

Typical mass-production yield for H80 brass in the FeCl₃ system is 97.8%, within an observed range of 97-98.1%. The dominant yield-loss modes are photoresist pinhole defects and rinse-water contamination. Improving incoming sheet quality and photoresist coating consistency gives the highest yield-improvement leverage for this formula.

Typical Applications

Typical applications for H80 brass processed with FeCl₃ include lead frames, busbars, flexible heater elements, RF gaskets, and precision electrical contacts. The formula's tolerance band and yield make it well suited to medium-to-high-volume precision flat parts.

More Copper & Brass Formulas

Other formulas in the same material family.

C1020 OF Copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Through etch (double-sided) C1100 T2 copper FeCl₃ Half etch (single-sided)

Frequently Asked Questions

Minimum producible hole diameter ranges 60-600 μm across the 0.05-0.5 mm thickness band, following the 1.2× material-thickness design rule. The smallest holes are only available on the thinnest stock; attempting holes below the floor for a given thickness causes yield to drop sharply.

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WET Etched runs production wet chemical etching lines using the FeCl₃ chemistry. Send us your part drawing and quantity for a full process quote.

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