Re: Anode material...how to tell?
As long as the anode is made of one material, you can measure it's density.
1. Weigh it and convert ounces to pounds, e.g. 1.3 oz / ( 16 oz/lb ) = 0.08 lb.
(or you can work in grams, e.g. 37 g)
2. Dunk it in a measuring cup with some water and measure it's volume. The mL scale should be more accurate than the fluid oz scale. Then convert to cubic inches, e.g. 14 mL / ( 16.4 mL/in^3 ) = 0.85 in^3
(or work in grams and leave the volume in mL, e.g. 14 mL)
3. Divide the weight by the volume to get the (weight) density, e.g. 0.08 lb / 0.85 in^3 = 0.094 lb/in^3
(or 37 g / 14 mL = 2.6 g/mL mass density)
4. Compare to the known densities
Magnesium .063 lb/in^3 (1.7 g/mL)
Aluminum .098 lb/in^3 (2.7 g/mL)
Zinc .26 lb/in^3 (7.1 g/mL)
So the example above would've been for an aluminum alloy anode.
Comment: The zinc alloy used really is mostly zinc.
Military specification MIL-A-18001K calls out 99.314% zinc minimum, with very small amounts of aluminum, copper, cadmium, iron and lead. So you should just be able to compare to the density of pure zinc. Magnesium alloy and aluminum alloy anodes are similar--mostly made of magnesium or aluminum.
