[kitcarbp]

I spent about $45 including shipping for the Henkel prep and alodine, no anodizing shop near me would touch this job for under $100 (min set-up). The acid prep cleaner and alodine solution I mixed up (with water) is reusable for coating more alum. parts as I go through my build, thus stretching the $45 beyond these 2 parts. (Henkel quotes over 100 square feet with quantities I purchased). My goal was corrosion protection not appearance here.

This Alodine process (without primer/topcoat) while ok for moderate corrosion protection in this applciation, on airplanes its intended as the first step for treating the alum. In airplanes, they typically apply primer and top coats on top of Alodine prepared parts on what I have read. For the fuel tank fill plate application here, my thinking was alodine should be sufficient for pump gas, Alodine coatings are used by folks like ATL (supplier for my 45 deg neck) for their fill plates as well.

Regarding the powder coat question, for this application for a fuel tank, powercoating is not the preferred coating for long term durability, i.e. exposed to gasoline) info I found is that anodizing and alodine are two accepted coatings on Al for fill plates.