Buffing / Polishing aluminum to look like chrome?

[Fordiesel69]

In particular a motorcycle side plate on the engine. Its a nice polished aluminum when new, now it is dull and has some VERY slight pitting.

What is the process shops use to re-polish this aluminum during the restorations. It looks like brand new....

I have a bench buffer and the sticks of compounds but I must be doing something wrong. I was thinking of wet sanding it first to see if some of the pitting will level out.

Thoughts?

 

[loyd]

Use a flat sanding block first with 400 or 600 grit to level the piece then switch to 1000 or 1200. Once you have the pits levelled out and a uniform appearance you can start buffing. I use a spiral-sewn buff with tripoli for the initial buffing then switch to a loose flannel buff and white rouge for the final polish.

 

[Fordiesel69]

Can you elaborate on the buffing wheels and the compounds. I am not familiar with spiral sewn w/ tripoli and flannel with white rouge. All I have is a harbor frieght buffer with a red stick and a green stick of compound.

 

[razel]

Not sure how bad your aluminum is but here is a great example of choosing the right cut of polish:

http://www.meguiarsonline.com/forums/showthread.php?57780

The good news since it's aluminum it's soft and very easy for you to do corrections. Have fun. By the way that was all done by hand! I'm not sure how long though.

 

[JimPghPA]

BTW, rough metal surfaces are good at transferring heat, due to having a large surface area on the microscopic scale.

Polished (like a mirror) surfaces are poor heat transfer surfaces, due to having much less surface area on a microscopic scale.

Motorcycle engines with a mirror finish on the fins on the cylinder are poor at transferring heat compared to the same engine with rough finish on the fins.

A single side plate is probably not enough surface area to make any significant difference, but if you do learn how to get a fine finish think twice before polishing major heat transfer surfaces like the fins on the cylinder(s). You could end up with an engine that overheats in warm weather.

 

[Vikas]

On the similar line, what is the best way to bring the luster back to chrome aka bathroom fixtures? They have lots of microscratches and look dull

 

[Fordiesel69]

Temps are not a problem, its a decorative side cover for the flywheel. It was meant to be polished from the factory. Years of neglect has it looking [censored].

I also have a few very old Kirby vacuums that could use a good polishing.

 

[grampi]

Polished aluminum will never look like chrome, no matter how shiny you get it...doesn't mean it won't look good though...

 

[qwertydude]

You can actually get aluminum to look like chrome. The problem is it won't last. It'll dull to a normal polished aluminum look rather quickly.

You need to wet sand it completely flat and go up to 2000 grit. Then you can buff it with finer and finer compounds. After that then you can use a fine metal polish like Mothers Incredible Billet. It will look as good as chrome. But like I said it'll go dull very quickly.

It might actually be better to just get it actually chrome plated.

 

[grampi]

Originally Posted By: qwertydude
You can actually get aluminum to look like chrome. The problem is it won't last. It'll dull to a normal polished aluminum look rather quickly.

You need to wet sand it completely flat and go up to 2000 grit. Then you can buff it with finer and finer compounds. After that then you can use a fine metal polish like Mothers Incredible Billet. It will look as good as chrome. But like I said it'll go dull very quickly.

It might actually be better to just get it actually chrome plated.


I've seen aluminum polished to a mirror finish and it still didn't look like chrome....chrome is a brighter color than polished aluminum...not saying aluminum can't be as shiny as chrome, cuz it can be, it just doesn't look the same as chrome...and you're right, it is much more difficult to keep it looking nice compared to chrome....

 

[qwertydude]

Actually chrome's reflectance is less than polished aluminum. Aluminum is the most reflective material second only to silver. It's why they use it for telescope mirrors.

You might be thinking of chromes distinct bluish cast compared to aluminum which if not perfectly polished has a whitish cast. So yeah aluminum can't be made to look like chrome. But I think the OP's original question pertained to polishing aluminum to make it as reflective as possible like chrome.

 

[grampi]

Originally Posted By: qwertydude
Actually chrome's reflectance is less than polished aluminum. Aluminum is the most reflective material second only to silver. It's why they use it for telescope mirrors.

You might be thinking of chromes distinct bluish cast compared to aluminum which if not perfectly polished has a whitish cast. So yeah aluminum can't be made to look like chrome. But I think the OP's original question pertained to polishing aluminum to make it as reflective as possible like chrome.


Interesting...all I know is when a polished aluminum piece is compared side by side with a chrome piece, the chrome looks like a brighter color to me...not shinier, just a different color...

 

[strat81]

Originally Posted By: grampi
Interesting...all I know is when a polished aluminum piece is compared side by side with a chrome piece, the chrome looks like a brighter color to me...not shinier, just a different color...


You're right, they do look different.

Put polished stainless steel, aluminum, nickel, and chrome next to each other and you'll have finishes that look very similar, but will be different.