How to get a mirror finish on aluminum

[davidyat]

I was given a block of aluminum for a project by a friend. I would like to get it to a mirror finish if there is a way. Don't know what kind of aluminum it is. I've tried a buffing wheel with the green high polish rouge and then tried my random orbital sander with 2,000 grit sandpaper, then polishing. Close, but I still can see lines and grooves (really small) in the block. OK, can anyone guide me in the right direction?
Grasshopper

 

[Zeb]

Aluminum will oxidize after polishing, so a dip in lacquer ...or... a light dip in alodine and rinse would work. Chemical conversion would work better as lacquer won't stick to polished aluminum well.
Maybe some of this stuff?

Mothers 05100 Mag & Aluminum Polish, 5 oz.​

 

[minh-thanh]

Hi Grasshopper !

I only polish aluminum once or twice and very little
If it still can have lines and grooves - try polishing in the direction you sanded and at a slower speed, then at a higher speed to finish.

 

[ShopShoe]

I have had good luck following the recommendations in the link below. The proper compound with the right type of buffing wheel and usually a multiple-step process to reach completion.

As usual, I have no relationship with the vendor other than as a customer. Just to be clear, I did buy a kit of multiple buffing wheels and multiple types of compound, and I never use a wheel for other than the correspoding compound. I also have various small buffing wheels and points for use with my Dremel and Proxxon handheld rotary tools.

Link: Buff Wheel & Buffing Compounds Selection Chart - Eastwood

--ShopShoe

 

[Joe]

Not sure how it would work with your application but to maintain a polish on aluminum aircraft panels I would shake "the magic powder " out of a J and J baby powder bottle and buff the panel with a soft dry rag. Worked great, fast, easy and would last a year with regularly flown, hangar kept aircraft.
The "magic powder" ? White flour.

 

[bluejets]

Differing grades of wet and dry sandpaper, course to finer naturally, plenty of lube, so use either wd40 or mineral turpentine.
When all surface grooves removed, polish up with the usual metal polish like "glow".

 

[Gabe J DiMarino]

The trick is to remove all the lines from the previous grade of paper before moving to finer grades . I do 120, 180 ,200 ,240 ,320 , 400 ,500, 600 ,800 ,1000 some lapping compound then multi stage buff .Then semi-chrome or Mothers Paste . Polish in the same direction . If you get to 320 and see deep scratches go back a grade till the surface is uniform and the scratches are all the same depth . To get a true mirror is very labor intensive . You can have a very shiny part that is not a mirror .

 

[davidyat]

Thanks everyone. I'm getting a lot of advice and will try them.
Grasshopper

 

[ChazzC]

Go to Joe Pie YouTube Videos and search for "polish": you'll find lots of videos where he finishes an Aluminum part then finishes with emery cloth, Scotch-Brite & Blue Magic® polish and the results are beautiful.

 

[davidyat]

Chazz,
Do you have a phrase that I could put in the search engine of Joe Pie so I could get the video you are talking about. Polish and Polish Aluminum isn't working for me.
Thanks,
Grasshopper

 

[ChazzC]

Chazz,
Do you have a phrase that I could put in the search engine of Joe Pie so I could get the video you are talking about. Polish and Polish Aluminum isn't working for me.
Thanks,
Grasshopper

Try this; he's making a flat belt stepped pulley, involving turning, lathe filing and hand finishing. I'll look for one where he uses the metal polish.

 

[davidyat]

Thanks

 

[ChazzC]

I couldn't find the one I was looking for where Joe mentions Blue Magic®, but here he's making a small crank handle out of brass and after using emery paper he uses the polish.

 

[davidyat]

I was able to watch that one. Thanks

 

[stevehuckss396]

Used your sander to 2000 is great. Then use your sander with a scotchbrite pad until all the little scratches are gone. I actually have an 8 inch scotchbrite wheel.

Go to the buffing wheel with a red buffing compound. If you see a little scratch cross the scratch with the buff. By that I mean turn the part so the wheel crosses the scratch at a 45 or greater degree. You should go from scotchbrite to shine very quickly. Once all the scratches are gone stick a screwdriver into the buff to remove the red compound from the wheel. Use a black compound. We used to call it black beauty. That will remove the marks from the red compound. Finish with speedy metal polish. It has carnauba wax in it so it will stay shiny a while. Use a good quality car wax and it last even longer.

 

[michael-au]

Brasso works well on aluminium also

 

[Niterate]

lol.. was schooled in this art from this fellow's tuning channel . . Jaffromoble (this is the 8th in series if you want all the gory details.. ) think it all boils down to start at 320 and every grit change is a 90deg change in sanding directlion when the previous 'grain' is no longer visible .. ending in the obligatory machine buff where possible ..

 

[transon1]

I was given a block of aluminum for a project by a friend. I would like to get it to a mirror finish if there is a way. Don't know what kind of aluminum it is. I've tried a buffing wheel with the green high polish rouge and then tried my random orbital sander with 2,000 grit sandpaper, then polishing. Close, but I still can see lines and grooves (really small) in the block. OK, can anyone guide me in the right direction?
Grasshopper

Use a good grade of metal polish like the Blue Magic that was recommended. After you obtain the finish you want then apply a high grade of wax polish such as Renaissance micro crystalline wax polish.

 

[Dubi]

Brasso works well on aluminium also

Toothpaste also works very well.

 

[Rocket Man]

I don't build beautiful projects anymore. Life is too short to waste my life trying to keep an old project polished and looking like a master piece. If you build a project that does NOT run but looks beautiful it will win 1st place Best of Show Blue Ribbon Award. Why does beauty always take priority over how much time you worked on a project, how hard it was to build and how well it runs?

I know a man that owns a used car lot, he buys the uglies cars he can because they sell at a very low price. He has the ugly cars painted then sells them for $2000 more than he paid for the car. He laughs all the way to the bank because he can sell a gallon of paint for $2000.