--- title: "Anodizing Chemical Dosing Calculator" description: >- Free anodizing chemical dosing calculator. Get exact quantities for sulphuric acid, caustic soda, nickel acetate sealing, and desmut bath make-up or... canonical: "https://www.saravanaconsultancy.in/calculators/chemical-dosing" source_url: html: "https://www.saravanaconsultancy.in/calculators/chemical-dosing" md: "https://www.saravanaconsultancy.in/calculators/chemical-dosing.md" last_modified: 2026-05-24 --- Free Calculator # Anodizing Chemical Dosing Calculator Calculate exact chemical quantities for bath make-up or replenishment. Covers sulphuric acid anodizing, caustic soda etch, nickel acetate sealing, nitric acid desmut, and alkaline degreaser baths. ## Inputs Bath make-up Replenishment Bath / process Sulphuric acid anodizing bath (Type II) Caustic soda etch Nickel acetate sealing Nitric acid desmut Alkaline degreaser Tank volume (litres) Working volume of the process tank Target concentration (g/L) Type II standard: 180 – 200 g/L H₂SO₄ Current concentration (g/L) From your last titration result ## Dosing quantities Chemical quantity — Volume of commercial chemical — Top up with DI / soft water — Select a process above to see dosing guidance. ⚠ Always add acid to water — never water to acid. Add slowly with continuous stirring. Sulphuric acid addition is highly exothermic. Allow bath to cool to < 22 °C before use. ⚠ Caustic soda dissolves exothermically. Add flakes or beads in small portions to water with continuous agitation. Do not fill tank fully — allow for volume expansion and foam. Heat to operating temperature (55–65 °C) only after full dissolution. ## [Bath chemistry reference](https://www.saravanaconsultancy.in/blog/anodising-bath-chemistry-reference-india) — standard concentrations | Bath | Chemical | Target (g/L or % v/v) | Operating temp | Notes | | --- | --- | --- | --- | --- | | Sulphuric acid anodizing (Type II) | H₂SO₄ 98% | 180 – 200 g/L | 18 – 22 °C | Monitor by titration weekly; aluminium build-up > 20 g/L slows growth | | Hard anodizing (Type III) | H₂SO₄ 98% | 150 – 180 g/L | −2 to +2 °C | Lower acid than Type II; chiller critical; add glycolic acid additive optional | | Caustic soda etch (decorative) | NaOH flakes/beads 99% | 40 – 60 g/L | 55 – 65 °C | Add gluconate 1–2 g/L to control etch rate; Al build-up 10–15 g/L = change bath | | Caustic soda etch (aggressive) | NaOH flakes/beads 99% | 80 – 120 g/L | 60 – 70 °C | For heavily machined surfaces; watch weight loss on 6063 | | Nickel acetate sealing | Ni(CH₃COO)₂ sealing salts | 5 – 8 g/L | 95 – 98 °C | pH 5.5 – 6.5; use DI water only; 1 min per µm of coating | | Nitric acid desmut | HNO₃ 65% | 20 – 30 % v/v | Ambient (20 – 25 °C) | For 6061/6063; add HF 1–2% v/v for 2xxx alloys (copper smut) | | Alkaline degreaser | Proprietary powder (pH 11–12) | 30 – 50 g/L | 50 – 60 °C | Spray or immersion; rinse conductivity < 50 µS/cm before etch | ### Safety notes - **Sulphuric acid:** Always add acid to water (not water to acid). Exothermic — allow bath to cool after addition before energising. - **Caustic soda:** Add in small portions with agitation. Hot caustic splashes cause severe alkali burns. Full PPE required. - **Nickel acetate:** SVHC under REACH. Maintain control measures for Ni dust during powder weighing. Waste bath requires Ni removal before discharge. - **Nitric acid:** Oxidising acid — keep away from organics. Fume extraction required. Do not mix with HF without proper training and PPE. ### Need help sourcing these chemicals in India? We vet suppliers for purity, consistency and safety data. Our [chemicals sourcing guide](/buy/anodizing-chemicals) lists verified Indian distributors with typical pricing for industrial quantities. [Chemicals sourcing guide](/buy/anodizing-chemicals) [Talk to an expert →](/contact) ## Frequently asked questions How much sulphuric acid do I need for an anodizing bath? Standard Type II sulphuric anodizing runs at 180–200 g/L of H₂SO₄. Industrial sulphuric acid is supplied at 98% concentration with a density of 1.84 kg/L. For a 1,000-litre bath at 190 g/L: 190 kg of H₂SO₄ ÷ 0.98 = 194 kg of commercial acid = 194 ÷ 1.84 = 105 litres by volume. Always add acid to water, never water to acid — the dissolution is highly exothermic. What concentration of caustic soda is used for anodizing etch? Decorative etch: 40–60 g/L NaOH at 55–65 °C for 1–3 minutes gives a matte, even finish. Aggressive etch: 80–120 g/L at 60–70 °C for heavily machined or as-cast surfaces. Add 1–2 g/L sodium gluconate to inhibit over-etching and to complex dissolved aluminium, extending bath life before a dump is required. How do I make up a nickel acetate sealing bath? Dissolve nickel acetate sealing salts in de-ionised water (DI water is essential — tap water causes white smut on the coating) at 5–8 g/L. Adjust pH to 5.5–6.5 using acetic acid (to lower) or sodium acetate (to raise). Operate at 95–98 °C. A 500-litre bath at 6 g/L requires 3 kg of sealing salts. Seal time: 1 minute per micron of coating thickness. What chemicals do I need for desmut after caustic etch? The standard desmut for 6xxx series aluminium is 20–30% v/v nitric acid (HNO₃ 65%) at room temperature for 1–3 minutes. For high-copper alloys (2xxx series), add 1–2% v/v hydrofluoric acid or use a proprietary ferric sulphate desmut. A 500-litre bath at 25% v/v requires 125 litres of nitric acid concentrate. How often should I check and replenish [anodizing bath chemistry](https://www.saravanaconsultancy.in/blog/anodising-bath-chemistry-guide-india)? Sulphuric acid: titrate weekly; replenish when below lower limit (typically 175 g/L). Caustic soda: daily titration on a busy line; dump when aluminium content exceeds 15 g/L. Nickel acetate seal: measure pH and Ni² ⁺ concentration daily; replenish when Ni²⁺ drops below 0.8 g/L. Degreaser: measure free alkalinity weekly; dump when soil loading causes part failures at rinse check.