# Magnetic Aluminum....



## TOOLMASTER (Jul 6, 2016)

http://www.adorama.com/mt249564.html?gclid=CIiDqvHk380CFQqoaQodjawF2g



Aluminum legs (type 3 hard black anodized)

maybe i'm behind on metallurgy but I didn't think aluminum was magnetic.


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## Ulma Doctor (Jul 6, 2016)

the tubes are made of steel, but it made me take a double take  :


*About Matthews Mini Slider Stand*



• Steel Tubes
• Aluminum Legs (type 3 hard black anodized)
• Military Black Chrome
• Machined, Welded Junior Receiver


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## strantor (Jul 7, 2016)

I must be missing something... where does it say anything about being magnetic? 
or do you have one of these and put a magnet to it and found it to be magnetic?


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## TOOLMASTER (Jul 7, 2016)

the (tubes) are the round ones used for height adjustment .


the legs are,, well the legs


the lady i talked to at the company said it (ALUMINUM)was a typo, and didn't think it was a big deal....

they are 1.5 pounds heavier too....the whole point of buying these was for the weight....there are cheaper options at this weight...


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## dlane (Jul 7, 2016)

They must of removed the typo, didn't see any reference to magnetic


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## savarin (Jul 7, 2016)

I want an aluminium magnet for my broom


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## TOOLMASTER (Jul 7, 2016)

steeluminum?


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## strantor (Jul 7, 2016)

TOOLMASTER said:


> the (tubes) are the round ones used for height adjustment .
> 
> 
> the legs are,, well the legs
> ...



ok, I get it now since your edits. 
Seems like a clear case of false advertisement. 
I'm not sure how well you play the part of an A-hole over the phone, but a particularly skilled individual might be able to convince them that their typo is going to cost them the price of return shipping, that won't be covered by any restocking fee.


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## Fabrickator (Jul 7, 2016)

savarin said:


> I want an aluminium magnet for my broom



Me too.  The best thing I've found is to wrap a microfiber type towel (HF) over it.  It seems that the chips get hooked in the fine loops. Works pretty good, but not 100%.


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## Andre (Jul 7, 2016)

We've always joked about needing brass magnets for the range. Those basket type brass brooms don't pick up .22 casings well.


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## 12bolts (Jul 8, 2016)

Yep theres your typo


TOOLMASTER said:


> ....... said it (ALUMINUM)was a typo......


You yanks cant spell Aluminium

Cheers Phil


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## higgite (Jul 8, 2016)

12bolts said:


> Yep theres your typo
> 
> You yanks cant spell Aluminium
> 
> Cheers Phil


We can spell aluminium, we just can't say it. 

Tom


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## mmcmdl (Jul 8, 2016)

The best magnet I ever owned picked up everything from wood , non-ferrous metals , steel etc . We all know what it was made of . Unobtaniun of course ! I now cannot find it but I'm positive I stuck it to a rafter in the garage .........................


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## Fabrickator (Jul 11, 2016)

Once you get rid of the wads of swarf, the best aluminum picker-upper is a good shop vac.  I have a shop vac parked next to my lathe and mill and I put nothing but aluminum in it. I also have a 32 gallon trash can dedicated for aluminum swarf. When the can gets full (about 45#'s), I take it to the local recycling location and by keeping it pure with no trash, wood or steel, they give me the clean market value for it, about $.34 pound.


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## Ulma Doctor (Jul 11, 2016)

mmcmdl said:


> The best magnet I ever owned picked up everything from wood , non-ferrous metals , steel etc . We all know what it was made of . Unobtaniun of course ! I now cannot find it but I'm positive I stuck it to a rafter in the garage .........................



you may wanna look next to the left handed metric munkee wrench, you know right next to the muffler bearing separator, that's next to the flux capacitor charger!


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## strantor (Jul 11, 2016)

Andre said:


> We've always joked about needing brass magnets for the range. Those basket type brass brooms don't pick up .22 casings well.



For a while I've been sitting on an idea for this. 
I shoot in my back yard and been wanting a way to recover my brass from the grass...
Brass (and aluminum) are *para*magnetic (brass might be *dia*magnetic at certain temps, not sure).
Just because they aren't *ferro*magnetic doesn't mean there is no magnetic interaction possible with them.
The video below gives a fairly consise explanation & demo.
A high power magnet moving past a piece of brass or aluminum at a high rate of speed should (in the physics simulations inside my head) induce eddy currents in the brass/alum., which create their own magnetic fields which oppose the those of the moving magnets. 
If a disk of magnets were mounted on a high speed rotating thing, like a weed whacker, and passed over copper/alum. pieces, those pieces **should** (in my head) become magnetized for a brief period, just long enough to the flung out in all directions.
If there were a cowl around the magnetic disk to catch the flying brass casings, then maybe it could functionally be a "brass vacuum" that doesn't suck up dust or grass.
I plan to build one in the next few decades and test the concept, but if you beat me to it, at least give me an honorable mention. A million bucks would be even better.


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## John Hasler (Jul 11, 2016)

strantor said:


> A high power magnet moving past a piece of brass or aluminum at a high rate of speed


Much simpler to just drive a coil with AC.


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## strantor (Jul 12, 2016)

John Hasler said:


> Much simpler to just drive a coil with AC.


The physics simulations in my head don't include any complete entries for "brass interactions with AC coil."
however I envision something in between a tattoo gun with the speed turned up to 11, and capacitor run motor with no run capacitor.

A spinning magnetic disk is easy for me to envision; moving magnets sling brass outward. 
you have a vector; a speed(RPM) and a direction (tangent of the rotating disk).

An AC coil does what? vibrates brass? I'm not sure.
You have a speed (Hz) but do you have a direction? Where is the vector?
Isn't this why single phase AC motors require capacitors to "cheat" around this lack of vector?

I'm not saying it wouldn't work, I'm just saying it's not obvious_* to me*_ how it would work. 
And plus, I picture this thing as an attachment to my weed whacker, used out on my range, hundreds of yards from any AC power source. If it were AC powered I would need to lug a generator around. Or batteries and an inverter.


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## Andre (Jul 12, 2016)

It is possible to induce a magnetic affect on non ferrous metals, Matthias Wandel shows a demonstration of this in one of his induction motor videos. 

Instead of picking up brass yourself, make a trough in a "V" shape out of metal for the first foot or so in front of the firing line. (If there's a concrete pad you're standing on). Angle it 1-2 degrees to one edge of the range, and make a strainer bucket for the low end. Sweep the brass into the trough, wait for it to rain or use a garden hose to carry away the brass into the strainer bucket for collection.


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## Tony Wells (Jul 13, 2016)

Aluminum (Aluminium) is paramagnetic, albeit with a low relative permeability of 1.00002, a vacuum being the reference. That's pretty low in the real world.


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## strantor (Jul 13, 2016)

Tony Wells said:


> Aluminum (Aluminium) is paramagnetic, albeit with a low relative permeability of 1.00002, a vacuum being the reference. That's pretty low in the real world.


(Assuming you're commenting on the non-ferrous bit-picking weed whacker "vacuum" concept...)

The permeability isn't the important factor here. If you tried to make an electromagnet out of aluminum, yeah, it would suck (or not, actually).
It's aluminum's conductivity that matters; it's a great conductor, not as good as copper, but good enough.
When a conductor (any conductor of any material) cuts through magnetic lines of flux, a current is induced in the conductor, and that current creates its own magnetic field (even in aluminum)

If you've ever taken apart an induction motor, you've probably noticed the the two cast end caps on the rotor. Those are just the visible ends of a solid cast "squirrel cage" that exists within the rotor.
It's the aluminum bars (conductors) inside that react with the stator field in the manner described above, that makes the motor spin.
The steel laminations of the rotor just provide an easier path for the magnetic flux to reach the conductors.


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## Tony Wells (Jul 13, 2016)

But isn't that what you are trying to do? Make an electromagnet out of aluminum by means of induced current?


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## strantor (Jul 13, 2016)

Tony Wells said:


> But isn't that what you are trying to do? Make an electromagnet out of aluminum by means of induced current?


Sorta? But not really...
I wish I were a better wordsmith. I'll default to my silver bullet, visuals...


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## strantor (Jul 13, 2016)

I was looking for better examples and ran across "eddy current separators" - it turns out they're already using my idea (or close to it) to separate out aluminum, brass, palladium, gold, silver, etc from recycled trash.

short & sweet:





This video shows the magnets in action:






Maybe a better explanation of eddy currents, Lenze's Law, etc.


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