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Patina Calculator — Chemical Patina Solutions
Calculate chemical patina solution quantities for metal sculpture finishing.
How We Calculate This
How Patina Calculation Works
Total solution (ml) = Surface area × Application rate × Coats × Waste factor
A brushed thin coat uses about 0.005 ml/cm² (50 ml/m²) — an almost-dry brush dabbed onto hot metal. Multiplying by your number of coats and the waste factor gives the total finished solution volume.
Chemical (g) = Solution volume (litres) × Concentration (g/L)
The dry chemical is dissolved to a verified concentration: liver of sulphur 20 g/L, ferric nitrate 10 g/L, cupric nitrate 100 g/L and bismuth nitrate 42 g/L (Science Company recipes; Hughes & Rowe). For these dilute solutions the dissolved solid adds negligible volume, so the water needed is taken as the full solution volume — mix water first, then stir the weighed chemical in. Immersion or dip patinas use far more solution than the brushed figure here.
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates. Always verify quantities before purchasing materials.