720 Rule Anodizing Calculator

  Surface Area     In²  
  Thickness     mils (0.1-1)  
  Current Density     Amp/Ft²  
  Set Current     Amp  
  Time     Minutes  
  Peak Voltage     Vdc  
You can save this page to your computer so you don't have to come to the web site to use it - just click File | Save Page As (FF) or File | Save as (IE).
Based on GramSlam's excel sheet for 720 rule calculations. Calculated values are rounded to two decimal places.
To use, simply supply values for the first four numbers. The last three numbers will be calculated as you type. You can specify the surface area in either square inches or square feet.
The LCD process is designed for current densities between 3 and 6 amps/ft². The 1:3 acid ratio has been successfully pushed to 12 amps/ft² with aggressive agitation and careful temperature control.
Best dye results are obtained with a thickness between .5 and 1 mil.
Peak voltage is a function of several factors: distance from part to cathode, acid strength, amount of dissolved aluminum in the solution, etc. Yours may vary by several volts without necessarily indicating a problem.