Questions about quality
ARE ALL ZINC ANODES THE SAME?
No they are not. The chemical composition of the anode has a significant effect on it's ability to protect a vessel or structure.
CHEMICAL COMPOSITION. . whats that?
A zinc anode isn't just zinc. It's an alloy with other metals added. Great care is taken to avoid impurities. In the 1950's the US navy developed an alloy that is still in use. The most recent specification is called MIL-A-18001-K
WHY SHOULD I USE MIL-SPEC ZINC
Because it will consistently keep working by sacrificing itself. Your Mil-Spec
anode will avoid the build up of a passivated coating on it's surface that would stop it from doing it's job. It will also be activated.
WHAT CAUSES PASSIVATION?
Mostly iron oxides that result from unwanted iron in the alloy.
DOES A ZINC ANODE CLAIMED TO BE 99.99% PURE MAKE SENSE?
No; such an anode could still contain too much iron and would certainly be missing components needed to meet the MIL specification.
IS IT TRUE THAT SOME MANUFACTURERS USE RECLAIMED ZINC? Yes; apparently so. It is not possible to tell just by looking at a new anode, but by the time you find out it could be too late.Your defence is to buy from a manufacturer who can and does make regular metal analysis.
DOES AN ANODE THAT CLAIMS TO LAST LONGER MAKE SENSE?
No; if its not being eaten away it's not functioning correctly and your hull or other metal parts could suffer serious corrosion damage.
BUT WHAT ABOUT ALUMINIUM?
Yes; an aluminium anode can last longer while still providing full protection, but it is just as important that the special correct alloy is used . . . . Return to home page