Took these 2 Convoy S2+ and stripped the anodizing with Greased Lightening, polished with Mother’s aluminum polish, and buffed on a buffing wheel. Couldn’t find my buffing compound but there was still a little left on wheel. Figured they would come out more shiny. Maybe the knurling has something to do with the dull finish.
I’d say start with a 400 grit and work your way up and then finish with the buffing compound. You seem to have missed the sanding steps. Even though the surface may appear quite flat it probably isn’t.
Also doesn’t help with the knurling making for a very interrupted surface.
Aluminium won’t be shiny for too long, it oxidise really fast, it’s for this reason that it doesn’t corrode easily, the oxide protect the metal underneath
A lot has to do with the grade of aluminum. I glass bead Surefire’s and just use Mother’s California Gold Mag Polish and they come out like Chrome. This I do by hand. Try using a 3M scotch brite pad first, there are different grits like sand paper too, then add polish to the pad, then go polish and paper, paper towel, then a soft cloth and polish. The cheaper grades of aluminum take a little more elbow grease!!
That doesn't look like it is bare aluminum yet. Looks like the color coat is gone, but the anodizing is still there. Anodizing has no real color to it. It basically looks like dark or dirty aluminum. Put it back in Fresh greased lightning for 30 minutes, pull them out, clean with steel wool in a water bath and put them back in again. Repeat till the Aluminum comes out very light looking when you rub it with steel wool. Depending on the Anodizing, it can take hours. Ha III is a bear to ever remove all the Ano.
Try this if you can find it near you… Bar Keepers Friend, Cleanser, 12 oz (340 g) (Discontinued Item) This stuff is slightly aggressive so I use water to thin it out. I use it on all 3 Dragbikes because they have many pounds of polished billet aluminum on them, and after going many rounds they get filthy and sometimes I put them in Bike Shows, It works GREAT!
This first
Then what others are saying
you best chance of getting it shiny would be cutting of few tens of mm, (may even go deep enough to remove knurling) on a lathe, last pass should be slow, and very shallow, it will leave shiny, and smooth finish, than you can polish it. but it wont stay like mirror for long, like it was said, depends on a grade.
Seems like the GL wears out before the job is done. Originally tried to do both tubes in the same GL, one after the other but it didn’t seem to be doing much to the second tube so I used fresh GL on it also. Both were put in some fresh Greased Lightening just now, waiting.
greatly depends on the Al alloy, cheap flashlights are made with the rather softer type i highly doubt you’ll get good enough finish unless you remove a bit of material , For aluminium (surface work) i find that above 800 grit is good enough to remove enough without removing too much…
I am going to say what OL has already said.
Firstly you need to remove ALL of the anodizing. Most people think the color is the anodizing. It is NOT. The color is a dye that is absorbed into the anodizing which is relatively colorless. The anodized surface of the aluminum is MUCH harder than the original aluminum, that’s one reason why aluminum is often anodized. Another reason is that the anodized surface is porous and can accept stains of various colors.
Before you can polish previously anodized and colored aluminum, YOU NEED TO REMOVE ALL OF THE ANODIZING.
Most sandpapers use an aluminum oxide grit because it is very hard. Trying to polish anodized aluminum is like trying to polish sandpaper with sandpaper. Hard against hard.
On good anodizing, the type three stuff, I usually have to change the GL three times, to get the ano off. For the knurling, you really need a wire brush too. A brass one will work, or a softer steel, but steel will leave some marks. You will know when it’s all gone, because you will be able to rub on the mothers and wipe it off and the surface will shine like crazy. If it doesn’t, there’s still some ano on the aluminum.
Steel wool after the first 30 minutes, then steel brush after an hour. Looks totally different now. Might go for a third dip in GL.
Airplanes often have a layer of pure aluminum over the structural alloy to protect it from corrosion. It also makes it much shinier.
Work down to 4-0 steel wool, finer if you can get it. Then buff with fine grade rouge on a flannel wheel (easy on the rouge, it’s actually an abrasive). Clean with mild soap and water, dry, then use my secret weapon: Simichrome polish applied with an old T-shirt. Takes just a tiny dab of the Simichrome. Finish with a clean dry T-shirt and it will look like a mirror. Some aluminum alloys will polish so sweetly they will look like chrome. Beats Mother’s, Flitz, and anything else I’ve seen. Got me first prize in my class at a national motorcycle rally, need I say more?
Phil
Ended up dipping them 4 times, probably could have gotten away with 2 times. What I figured out is I was leaving the parts in the GL too long. Once the GL stops bubbling, remove the pieces, approximately 35 to 45 minutes in my case. Probably depends on how large the bowl is in relation to the size of the part being stripped, I was using a small bowl. Once GL stops working and the part sits in there the contaminates seem to reattach to the piece and form an ugly film. SawMaster, I will take the bike, thanks.
Yes, it does depend on how much of the GL you use. The more in the container, the longer it lasts, to an extent. Also, it matters which type of Ano. On a Maglite I can leave it in an hour and it continues to work, but on a type III, it's less time before it stops working. You can use a stronger cleaner like drain cleaner, but I have seen pitting with them, if left in very long. Again, the type of Ano and the quality of the Aluminum make it different for different lights.
I’ve heard that oven cleaner also de-anodizes but having never tried it you’re on your own there. Always best to take the gentlest approach when refinishing anything to minimize risk of damage.
Phil
Also temperature of the solution makes a big difference the hotter the faster chemical reactions take place.
I always use NaOH with a bit of hot water that kills the ano very fast…