Polishing aluminium?

[TimothyClaypole]

I'm currently polishing some 10mm tubing, I've been using my Dremel with felt wheels and the green polish that came with a Clarke polishing kit bought with a 6" Bench grinder.

I've been trying the bench grinder a bit but it's just not to the same shine as with the Dremel but the Dremel is painfully slow

The right one is unpolished, I've wet and dried them so far as they get marked up while cutting and sanding them to size.

The middle is the bench polisher and the left the Dremel. The second picture is a better idea of the finish from the Dremel.






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Should i get a smaller/new wheel and some specific aluminium polish if there is such a thing rather than what I would assume is general duty stuff supplied with the polishing kit?

Ideally I'd like to just finish them with the bench grinder but to the same standard as the Dremel.

 

[-Matt-]

Autosol metal polish. Found fairly everywhere.
If you have access to a lathe you could mount them, spin them and polish on that. If not then maybe pass a bolt through, tightened with a nut and sat in the chuck of a drill.

They should give a fairly decent shine straight off, but you may need a little wet/dry prep first.

 

[Mannyroad]

I fully agree with Matt. Bolt through middle, tightened by a nut on other end, into a drill chuck, spin it up and then first, if necessary, 1200/1500 grade wet & dry (used wet) will bring them up to quite a good shine. Then Autosol on a rag to get that chromed look.

 

[Graham Orm]

I fully agree with Matt. Bolt through middle, tightened by a nut on other end, into a drill chuck, spin it up and then first, if necessary, 1200/1500 grade wet & dry (used wet) will bring them up to quite a good shine. Then Autosol on a rag to get that chromed look.

Concurred completely with this...but...be very careful with that rag if you still use the drill.

You do know that they will go dull again fairly quickly being aluminum. You could lacquer them once polished.

 

[bugbear]

You might want to use Brasso and Silvo (or equivalent) to get a true shine; Autosol is (quite) coarse and (quite) hard, since it's target material is chrome, which is very hard indeed.

In fact, some vintage vehicle enthusiasts don't even use Autosol on chrome, because of its level on abrasion when viewed over the very long term.

The fact that you can use the stuff to abrade (sharpen) tool steel at Rc 60 and above is a clue...

Oh, and Grayorm is right, aluminium dulls quickly; it's very reactive.

BugBear

 

[TimothyClaypole]

I've been finishing them with Autosol already to get the residue from the hard polish off.

There's 14 bits on each thing I'm making so it was just a faster way to do them.

No lathe I'm afraid.

I've ordered some aluminium polish I've found so will give that a go with a new mop wheel.

 

[niagra]

http://www.frost.co.uk/standard-polishing-kit.html

I use this kit on my cheapo bench grinder. Seems to do the job, but as others have said, you need to apply some kind of lacquer and I have used this with some success. I brushed it on and you get no brush marks, just don't apply too much as you'll get drips.

http://www.frost.co.uk/por15-glisten-pc ... 473ml.html

 

[JohnPW]

A wax polish, eg car polish, will keep the shine for a long time. You don't have to apply lacquer.

 

[nanscombe]

If TimothyClaypole was making multiple sets of these, for his paint rack presumably, for other people would car polish eventually need re-polishing, or would lacquer provide a better, more long term option?

 

[Gerry]

Put a bolt through and clamp it with a nut. Mount it in a drill then use very fine wet or Dry with plenty of 3 in 1 oil and it will shine like a shithouse door on a frosty morning.

Gerry

 

[wallace]

aluminium is the easiest to get really shiny. I remove any dings by sanding, and go down to 400 grit. Then use a stiff stitched polishing mop. The best polishing compound I've found is the red one from silverline. To get the best lustre you need the mop to go pretty fast and generate some heat. I use a 10" stitched mop on my lathe on top speed 2800

 

[TimothyClaypole]

So the rougher mop rather than the "fluffy" one?

The brown says Aluminium and the Red Gold/Silver?


I've tried some of the Autosol Aluminium Polish and that seems much better than the metal polish but I think they need something harder as the finish is not as good under the surface polish.

 

[bugbear]

So the rougher mop rather than the "fluffy" one?

The brown says Aluminium and the Red Gold/Silver?


I've tried some of the Autosol Aluminium Polish and that seems much better than the metal polish but I think they need something harder as the finish is not as good under the surface polish.

Sounds like (surprise!!) you need a sequence of steadily finer grits.

BugBear

 

[TimothyClaypole]

There's 14 pieces on the small rack, they take long enough already. #-o

 

[bugbear]

There's 14 pieces on the small rack, they take long enough already. #-o

As your old woodwork teacher at school would tell you - moving to too fine a grit too soon is slower, not quicker!

BugBear

 

[chaoticbob]

I've tried some of the Autosol Aluminium Polish and that seems much better than the metal polish but I think they need something harder as the finish is not as good under the surface polish.

Hi Timothy. I'm new to woodworking and this forum, but have been mangling then polishing metal for some time. I would agree with BugBear. It sounds from what you say ('the finish is not as good under the surface polish') that you are trying to correct a poorly prepared underlying surface with a finishing polish. That will take forever!
As a time test I just polished 2 inches of a bit of half inch alloy bar from my cutoffs bin. It had been rattling around in there for a while, so was well oxidised and dinged.
I spun it at 700 rpm in the lathe, 2mins with P180 wet 'n' dry to get out the dings, then 30 seconds each with 320, 600, 1200, 2500 (all with a dab of oil on the paper) followed by 45 secs with something called MegaBrite (AlOx paste, local pound shop) on a bit of kitchen paper to get a mirror finish. So about 6mins allowing for cleaning off between grits. Obviously would have been quicker if the initial finish had been better. I don't know how that compares with the time you've been taking with the dremel, but I doubt it can be done much quicker without specialist gear. Total metal removed was about 75 microns on the radius. I know you don't have a lathe, but as pointed out by others, you can use a makeshift arbor and a drill.

Generally I have found that the softer the metal, the finer grit you need to go to before finish polishing. I think it's because the the grit 'digs in' more in soft materials and produces a coarser scratch pattern than with hard stuff. I've noticed this with wood as well.

Regards, Rob

 

[bugbear]

Generally I have found that the softer the metal, the finer grit you need to go to before finish polishing. I think it's because the the grit 'digs in' more in soft materials and produces a coarser scratch pattern than with hard stuff. I've noticed this with wood as well.

It also means harder steels take a finer finish from the same sharpening media I had an extreme run in with this
effect when trying to remove the ribbing from a butcher's steel to make a scraper burnisher. The super hard steel
took a reasonably high polish from 60 grit AlZi :shock:

BugBear