→ mr4lexndr.github.io/anodising-guide
A calculator and process guide for Type II sulfuric acid anodising, in one static page.
- 312 rule calculator — solves in all three directions: time, thickness, or current density
- Cell current from surface area, in mm² / cm² / dm² / m² / in² / ft²
- Voltage ceiling and supply headroom for constant-current mode
- Acid strength read off a hydrometer: % w/w against specific gravity, °Baumé and g/L
- Tank sequence — shot blast → degrease → etch → desmut → anodise → dye → seal
No build step and no dependencies. index.html is the whole site; open it locally in a
browser or edit and push, and GitHub Pages redeploys from main.
t = 3.12 × T / J T = t × J / 3.12 J = 3.12 × T / t I = J × A
t minutes · T microns · J A/dm² · A dm² · I amps
The constant — 312 amp-minutes per square metre per micron — carries a current efficiency of roughly 85 %. It is the metric twin of the imperial 720 rule, and the two agree within about 2 %.
Working numbers for a small shop, not a specification. Anything critical wants a real thickness measurement.