Keeping turned aluminum shiny

[rocketsled]

I made some standoffs for a friend's motorcycle. He wanted them in steel as that fits the look he's working towards


Untitled by Matey-O, on Flickr

I was using carbide and didn't bother harpening a HSS bit for a better surface...for grins I chucked up a bit of scrap aluminum to show him what he could have had...a little automatic feed and a little Mother's aluminum/Mag polish and it looks like a mirror surface.

But does the Aluminum polish seal the surface, or would it start to look oxidized and crappy after a bit in the Real World? Any recommendations on treating it so it remains mirror shiny?

[Carld]

A can of clear coat spray paint from Wally World will work.

[garagemark]

Almost all polished aluminum wheels are clear coated. That is by far the best way I know of.

[Rosco-P]

Have it clear anodized.

[firbikrhd1]

I am going to have to respectfully disagree with the idea of clear coating aluminum parts. Here in South Florida we have plenty of humidity and salt air. Over the years I've seen many motorcycles with polished aluminum parts that were clear coated with bigger problems than the clear coat was supposed to prevent. Eventually the clear coat gets a small fissure in it, moisture can and will eventually creep in and corrosion begins under the clear coat. At that point the only thing you can do is remove the clear coat and re polish the parts to make them look even half decent again. This can be a difficult task and removing the remaining clear coat can cause the parts to be further damaged. I have witnessed this on both Japanese and American motorcycles with polished aluminum parts including engine cases, fork lowers and wheels.

My suggestion, and what I do to solve the problem is use an aluminum alloy with high corrosion resistance and polish it when it begins to look the least bit dull. I have made several parts for my bike and they still look as good as when I made them. Trust me, I am not a frequent polisher of my bike as I really don't enjoy polishing as much as I enjoy riding. One additional benefit is that uncoated parts seem to have a higher luster than coated parts.

[duckman]

I use a product called White Diamond, I polished a piece of aluminum 6 years ago spun it in the lathe, prepolished with a piece of scotch brite and followed with polish on a rag, it has been in my unheated garage, hot, cold, humid, and what ever else can happen it has retained about 97% of the original polish shine, I also polished some of the parts on my kit car motor, used a buffer for the primary polish and then used White Diamond on a rag for the final polish 5 years ago and its still shiny.

[rocketsled]

My suggestion, and what I do to solve the problem is use an aluminum alloy with high corrosion resistance and polish it when it begins to look the least bit dull. I have made several parts for my bike and they still look as good as when I made them. Trust me, I am not a frequent polisher of my bike as I really don't enjoy polishing as much as I enjoy riding. One additional benefit is that uncoated parts seem to have a higher luster than coated parts.

The problem comes from my choice in aluminum stock. Occasionally I'll find a mother chunk at the salvage yard with a '7075' in grease paint on it, but a lot of times it's...well, it sure IS aluminum! But the vintage is unknown.

Does Harbor Freight sell a Rockwell Hardness tester?

[rocketsled]

Cool, I'll give it a shot, then pitch the parts outside for the next storm and see how they weather.

One of the other problem I find is how soft a turned part is. It takes one fumbled drop or clank and the surface gets nicked. Is all aluminum this way and I just haven't noticed, or is there a typical hardening process 'professional' parts typically get?