Alodine Process for Protecting Aluminum

[kitcarbp]

I wanted to drop a quick note and share results I obtained using Henkel's Alodine process for protecting aluminum from corrosion and preparing it for paint if needed. The process was exactly as Henkel (supplier) instructed with supplied directions. This process has been used for decades protecting aluminum on aircrafts. This application in photo was for my fuel cell fill plate (shop made) and backing nut plate used on my plastic PE fuel tank. Preped with an acid to clean the aluminum (Alumaprep 33), rinsed in clean water and then apply the Alodine (brush or dip). It comes in clear or light gold as seen here in my results. The filler neck in photo is not freshly treated but will be soon. My motivation was an alternative to anodizing since its difficult to find anodizers who will do custom stuff at low cost. Took about 30 minutes from start to finish in my garage and I am happy with results. Follow the instructions and it works as advertised. I plan on doing this to all the small pieces of aluminum found throughout my car where I dont need it painted but need corrosion protection.

[Rick Parker]

This is very interesting, the pictures give the appearance of a gold dicromate, yet on aluminum in lieu of ferrous metal. Nice.

[bobcowan]

Why is this better than something like powder coating?

[tcrist]

What did it cost you for your plating supplies from Henkel's?

BTW, that should have been no more than a $35-$55 minimum charge at any plating shop. Gold Alodine (alodine 1200) on those parts should take less that 1/2 hour from start to finish.

Not trying to be a smart a$$. Just deal with this all the time in my line of work.

[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.

[FWB]

The coater i use charges 65.00 for a short run of that process, add 10.00 for a certificate of compliance...same cost for anodize of standard colors, clear, blue, red,and black.

[tcrist]

$45 is not a bad price and as you said, you can use it for more parts later. Also, you do not have to wait 3-5 days to get your parts back. Great information, thanks for posting.

[venum14]

Kitcarbp- You didn't list the Alodine P/N so I am curious. I have been using Henkel's Alodine 1001 for many years with great results. I have all the bare aluminum (foot boxes, trunk interior, aircleaner, intake, etc) on my Cobra Alodine coated.

The 1001 leaves the aluminum without color unless you leave it on too long and then it will give a gold/orange tint! I know beacuse I had to Scotchbrite it off and reapply with less 'soak' time.

[kitcarbp]

Venum, Yes I used the 1201 (gold) instead of the clear. Since its my first time using this product, I wanted to be able to see the coverage clearly visible using the gold color instead of clear. I may just pick up some of the clear stuff once I become proficient at this for some of the more visible parts.. I need to learn the best method of surface prep for appearance on alum when using the clear, scotchbrite for the brushed look I guess, and polishing for the high gloss look?

[kitcarbp]

Hey so I learned the other brand out there for Chromate converison processes for Alum. is Iridite ? Curious if anyone has tried that brand?