Anodizing Aluminum parts?

I see a lot of builds with parts being painted, powder coated, vapor blasted. I have yet to come across anyone who had something anodized. I'm sure it has been done. My understanding of anodizing its superior in a bunch of ways. I'm thinking of doing the lower part of my forks. Any input on the matter? Am I missing something that would cause issues? Thanks

I worked in an elctro plating shop when I was younger. The anodizing process is basically controlled rusting. There are three levels of anodizing. The first two are cosmetic and the last one is protective. Type I is very thin and mostly seen on cheap aluminum furniture and fixtures. It is usually clear. Type II is thicker and is what you generally see on automotive and motorcycle applications. It can be applied as a clear coat or dyed with a significant amount of colors. Type III is thicker and designed for components that will see significant wear. This is Military Specification grade and is more expensive. Any plating process may change the physical dimensions of the part being plated. Oxidation and Reduction - you can't have one without the other as my chemistry professor use to say. So you lose a little metal from the part being plated and hope you replace it with the same plating material. This is in microns and usually is not a problem except things like fork tubes or hydraulic cylinders which must be exact to work correctly. Any anodized surface can be scratched and any that have been dyed will eventually fade.

Rider52 said:

I worked in an elctro plating shop when I was younger. The anodizing process is basically controlled rusting. There are three levels of anodizing. The first two are cosmetic and the last one is protective. Type I is very thin and mostly seen on cheap aluminum furniture and fixtures. It is usually clear. Type II is thicker and is what you generally see on automotive and motorcycle applications. It can be applied as a clear coat or dyed with a significant of colors. Type III is thicker and designed for components that will see significant wear. This is Military Specification grade and is more expensive. Any plating process may change the physical dimensions of the part being plated. Oxidation and Reduction - you can't have one without the other as my chemistry professor use to say. So you lose a little metal from the part being plated and hope you replace it with the same plating material. This is in microns and usually is not a problem except things like fork tubes or hydraulic cylinders which must be exact to work correctly. Any anodized surface can be scratched and any that have been dyed will eventually fade.

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Great info, thanks a bunch. Sounds like this wouldn't be the route to go then. I appreciate the quick reply!

Ive had several parts anodized over the years. it not cheap but its not crazy money either. really steps the build quiality up a notch.

I assume your fork lowers are cast. Cast aluminum does not look good anodized it will be mottled and not uniform. parts need to be billet to look good.

Race tech offers fork tube anodizing in house. but its the type 3 or"hard anodizing" which produces a matte black finish. which is usually followed by powdercoat.

doc_rot said:

Ive had several parts anodized over the years. it not cheap but its not crazy money either. really steps the build quiality up a notch.

I assume your fork lowers are cast. Cast aluminum does not look good anodized it will be mottled and not uniform. parts need to be billet to look good.

Race tech offers fork tube anodizing in house. but its the type 3 or"hard anodizing" which produces a matte black finish. which is usually followed by powdercoat.

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Yes, my fork lowers are cast. On top of that they aren't in the greatest shape. Probably wouldn't end up looking good

Powdercoat or paint the lowers if they are too rough to polish. Anodizing it not a good finish for lowers as they get chipped and scratch from daily activities. Doc is right about cast parts. I forgot to mention the probability of mottling, glad he thought of it.

Paint or powder coat can be touched up with a brush and small bottle of matching paint. I touch up the PC on my GL1800 wheels about once a year with model car paint that I mixed to match. Gravel roads are hard on PC!

I have been told Prismatic makes a powder called "Tin Cup" which is very close to an original factory finish on fork lowers. I've seen pictures but never seen a finished part.

I anodized a part I milled for my boat.
Not overly difficult.
Just some sulfuric acid and a battery charger essentially.
Here is is raw and brushed:


Any after anodizing to match the rest of the boat hardware:

That turned out really nice.