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While I'm waiting for my engine to come back from the machine shop, I decided to clean up my aluminum valve covers. After hours of sanding, they are looking good. With all the time and effort invested I would hate to see them get scratched or marred. I am thinking of having them anodized. Has anyone done this or know of someone who did? Pros and cons? Any other solutions or suggestions for protecting them?
Alloy castings that contain a lot of zinc don't anodize well so I would suggest that standard alloy valve covers are not a good candidate for this process, when they come out of the bath there is a good chance they will be black. This process however makes a good surface to paint onto. Alloy extrusions such a C3 door sill plates are a good example of something that will anodize well.
The above is stuff I learned many years ago when I had motorcycle alloy motor components anodized. Unless there have been changes in the interim I believe this is the outcome you will likely get with valve covers. Check with your electroplater.
It would be worth investigating the options available using powder coating, I'm thinking of the finish that Edelbrock have on their "endurashine" intake manifolds here, unless I'm mistaken this is a powder coat finish, someone will chime in if I'm wrong!
Most powder coating will require a scuffed surface to properly stick. There are some companies that seem to have found a combination to clear over polished (billet usually) aluminum but it's costly and they don't have much of a guarantee.
I'm pretty sure endurashine and permashine are both shiny coatings that are top coated with clear (like a silver powercoat topped with clear powder coat) or are plated (same, shiny then clear)
Anodizing cast aluminum really depends on the base metal, some are more prone to ending up with black spots and uneven finishes than others that were designed to be anodized from the start. Same with polishing, some just don't get really "shiny" depending on the alloys
I had mine powder coated a grey color and then cleared, mainly to make them easier to keep clean as the raw cast finish absorbed every drop of oil/grease/sweat that went near them
Not sure if stock-looking is where you were heading but it is an option that is easy to take care of. You said you put a lot of work in them but I would have gone a different route. I would recommend just sending them off to Jerry Macniesh. He can restore/tumble them to a beautiful uniform satin aluminum finish. From that point you can clean them easily with any solvent and they will stay looking like new. The original '69 as-cast finish is similar but this process actually comes out looking better and more uniform in coloration. Dull aluminum to match the rest of the pieces in the engine compartment.
I don't think anodizing will accomplish what you want. They will still be subject to damage. The purpose of industrial anodizing is to prevent oxidation in addition to color coding of parts or assemblies. Powder coating would be a better choice.
I too om looking at different ideas on what would be most correctly/oe look and finish. I have 2 sets of covers one polished and one original and a bit tattered looking. My original finish set don't look like what most people end up doing, they are darker grey and dull finish.
I'd be curious what you're looking for and what you decide as I'm looking for ideas.
I've been looking into an alodine conversion. The Henkel Alodine 1201 will produce a golden color on the aluminum and its alloys. The alodine 1001 produces a clear finish. Both finishes can easily be painted. Alodine is widely used in aircraft applications. My concern is the high temperatures of valve covers and will it affect the coating.
I've decided not to anodize or use alodine on my aluminum valve covers. I hand sanded down from 150 - 1000 grit paper in 6 steps and then hit them with a buffing wheel and I know everyone is dying to see them (not really, lol). Well, here they are. First, a comparison between 1000 grit and buffing and then after with metal creme polish:
I think you will lose the luster on them if you powdercoat. Call a Harley-D shop and ask what they have for protecting polished aluminum...particularly parts that get 'engine hot'. They have some really good products for polished aluminum and chrome at H-D stores.
The next door neighbor has a very shiny pontoon baot. He uses "Shark Hide" on the raw aluminum pontoons. Keeps the water from dulling the polished pontoons.
Having said that I wonder what the big bulk tanker trailers use to keep them so shiny? I can't imagine they look forward to polishing them on a regular basis.
Anodizing valve covers
