Calculating the surface area?

[GramSlam]

Hello,

I have a quick question.

Does anyone know if you can accurately calculate the surface area of the parts in the anodizing tank using the resistance between the parts and the cathodes?

I am using a total of 256 in² lead cathodes. The parts I anodize have many little spots that are difficult to measure.

[Fibergeek]

It seems reasonable to think so, but there are two problems.

1. Bare aluminum will have an extremely low surface resistance, way too low for any common Ohm meter. A conductance measurement would be required.

2. Ionization effects; most liquids ionize when current flows through them, resulting in all sorts of variations in a resistance or conductance measurement. A repeatable measurement is next to impossible unless a liquid that won't ionize is used. Mercury would work, but this isn't practical.