Fisihiing aluminum

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sbarton22

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I am going to add a chunk of aluminum to one of my turnings. How does one finish it?

Do you sand? Is there some kind of great polish? Beall system?

Thanks in advance.
 
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Simplex

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I've been using aluminum quite a bit lately and have found that if you wet sand 220 thru 600 and then wet sand all the way through with micro mesh you get really good results. When I use the 220 thru 600 grit I actually pull the sandpaper across the aluminum in the opposite direction of rotation. The aluminum comes off quick using this technique but it is very effective. After I sand, I put it on the buffing wheel using white rouge buffing compound. One word of caution though: the aluminum will turn your buffing wheel black. I would recommend having a buffing wheel dedicated to aluminum. If you do all of the above, your aluminum component will come out very shiny (looks something like polished stainless steel).

Hope this helps.
 

Simplex

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Here is an example of what I am talking about; it's a front section I made on one of my original designs.
 

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sbarton22

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very nice! Does aluminum oxidize? Do you seal it somehow?

And when you say "opposite direction of the rotation", do you mean perpendicular or do you mean that you hand turn the lathe backwards?
 

Dalecamino

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For a brushed look, I wet sand with mineral spirits 220, 400 and 600. If I want a high polish, I then use Mothers aluminum polish with a blue shop towel then the white micro fiber cloth.
 

Simplex

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very nice! Does aluminum oxidize? Do you seal it somehow?

And when you say "opposite direction of the rotation", do you mean perpendicular or do you mean that you hand turn the lathe backwards?

You probably don't need to worry about the oxidation so much as you do scratching. Since aluminum is a soft metal is will scratch easily. I don't seal my aluminum but if I did I would probably apply a clear powder coat. I use T6 6061 aluminum.

You won't need to turn the spinde by hand. Since the lathe spindle rotates toward you, pull your sand paper away from you as you maintain contact with the piece.
 

Simplex

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You won't need to turn the spinde by hand. Since the lathe spindle rotates toward you, pull your sand paper away from you as you maintain contact with the piece.

I see. Now, color me stupid, but what does that actually do for you?

It's really based on personal experience than anything but I have found that aluminum will sand down faster and will remove scratches from the coarser grits to a greater degree.
 

Dalecamino

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Scott, I thought I would show you a couple of options since I have them available. One brushed as mentioned in my other post and, one polished. I like both. As Gary said, a protective coating will help with the scratching issue.
 

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frank123

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Alumninum responds well to wheel buffing if you have a wheel available, polish in steps through 2000 on the lathe then buff first with green HF stuff on a stitched wheel followed by plain old Turtle Wax (white) polishing compound on a loose muslin wheel. (you could also do the entire polish using different compounds if you have enough wheels and don't mind changing them).

Sisal wheels are nice for heavy cutting to remove scratches, but they are hard and you have to be pretty careful with the touch or you'll end up grinding instead of polishing.

You can also do the same on the lathe, but not quite as efficiently, using those compounds and a piece of paper towel by rubbing the bar gently across the turning piece then using the towel and moderately heavy pressure to polish it off. High speeds seem to work best with aluminum and heat buildup isn't the worry it would be with plastic or wood.

I finish coat the aluminum with Renaissance wax on a somewhat warmed up aluminum (hot water faucet warm) had have had it stay bright and shiny for a long time without going dull, but I work mostly with brass when I'm using metal for something (same procedure just a bit slower). I imagine any coating that will stick and is durable, shiny, and clear would work, CA included but I've never tried it on aluminum.

(FWIW, I coat everything with Renaissance wax from my guns and knives to polycarbonate headlight lenses. I love that stuff - it's expensive but a little goes a long way and it really works well)
 

azamiryou

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You won't need to turn the spinde by hand. Since the lathe spindle rotates toward you, pull your sand paper away from you as you maintain contact with the piece.

I see. Now, color me stupid, but what does that actually do for you?

It's really based on personal experience than anything but I have found that aluminum will sand down faster and will remove scratches from the coarser grits to a greater degree.

Just a guess, but if you don't move the paper, the spot that's in contact with the work probably quickly loads up and becomes ineffective. Since you're working on a cylinder, moving side to side won't make much difference. Assuming it tends to load where the work and paper first meet, then moving with the lathe would tend to feed loaded sandpaper in, and moving against the lathe brings fresh sandpaper into contact with the work.
 

soundman

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There is absolutly no problem getting aluminium, GLEAMING, GLEAMING.....GLEAMING.

but it does oxidise and it will leave you hands black if you handle it a lot.

Just look at any of those aluminium auto accessories....they look #@%&# fantastic when they are new, and the car detailers can keep em bright as.....but look at em after a few months or years...they don't look so gleamy any more.

The steering wheel on my old ride mower was aluminium, after a session "Riding the lawn", my hands where positivly black.

so sealing it somhow is a very good idea.....if it is a seperatable part, anodising is achieveble at home......a little dangerous, but hey so is cleaning the oven.

The problem with putting any sort of paint or varnish on it is that for good adhesion you need to etch or scratch....and there goes the polish.

Anodising I recon is the go.

cheers
 
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