# Weird effect with 10oz A-Mark SILVER Bullion



## stihl88 (Nov 3, 2009)

The weirdest thing happens when i drop a large N50 Rare Earth magnet onto my A-Mark Silver Bullion bar...

As i drop the magnet onto the bar it slows down at the last minute and as i pick it up again it is slow to pick up again also.
Is this normal for silver to have slightly weird magnetic property's?


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## Harold_V (Nov 3, 2009)

The explanation is beyond my ability to describe, but passing such materials through a magnetic field does react that way. It's common to have such a device as a damper on powder scales (for hand loading cartridges). I would imagine it's to do with currents being induced--secure in the knowledge that when a conductor crosses through lines of flux, electrical energy is the result. 

Now all we need is someone that has studied physics to make it clear (or to correct my comments) so both of us can understand the mechanics of the function. 

Harold


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## stihl88 (Nov 3, 2009)

Thanks for clearing this up Harold i was starting to think it might be a fake bar for some reason.

I was just going to ask you whether the same thing would happen if i tried it with copper and i just remembered i have a nice round bar of copper 1-1/2 by 1-1/2 plug so i tried it and the same thing happened but not quite as strong as with the silver and that definitely explains what you are saying about the induction produced here as we all know that silver is a better conductor than copper... Hmm i wonder if this magnet will work with aluminium


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## Irons (Nov 3, 2009)

Harold_V said:


> The explanation is beyond my ability to describe, but passing such materials through a magnetic field does react that way. It's common to have such a device as a damper on powder scales (for hand loading cartridges). I would imagine it's to do with currents being induced--secure in the knowledge that when a conductor crosses through lines of flux, electrical energy is the result.
> 
> Now all we need is someone that has studied physics to make it clear (or to correct my comments) so both of us can understand the mechanics of the function.
> 
> Harold


Absolutely correct Harold. It's like trying to turn the armature on a permanent magnet DC motor with the power leads shorted. Other metals will do the same thing.


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## stihl88 (Nov 3, 2009)

Yeah that's exactly what it feels like irons, kinda feels like in between the effects of the "retract and repel" effect of two magnets.
I make a lot of electromagnets for use with micro RC planes but the electro magnets (Actuator coils) are so small that none of these property's are evident apart from the obvious effect when a current is passed through the coil. 

Hell, take a squizz at my profile page here for some interesting little RC planes i make: http://www.rcgroups.com/forums/member.php?u=200902

The lightest RC plane Ive made so far is a 2 channel plane using an Infra Red receiver and the rudder is controlled by a micro actuator and it weighs 1g all up weight/battery and all, half the weight of a regular KLEENEX tissue believe it or not which is 2g. Unfortunately i don't have this plane pictured on my profile page yet but you can see my micro Spitfire which does fly also :twisted:


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## Irons (Nov 3, 2009)

stihl88 said:


> Yeah that's exactly what it feels like irons, kinda feels like in between the effects of the "retract and repel" effect of two magnets.
> I make a lot of electromagnets for use with micro RC planes but the electro magnets (Actuator coils) are so small that none of these property's are evident apart from the obvious effect when a current is passed through the coil.
> 
> Hell, take a squizz at my profile page here for some interesting little RC planes i make: http://www.rcgroups.com/forums/member.php?u=200902
> ...



I'm impressed. What's the flight time with that battery? Mount a camera and get in the Intel business. 8)


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## metatp (Nov 3, 2009)

It may be very similar to the Eddy current effect you get when you drop a magnet down a copper tube. It slows down the rate of speed.

Tom


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## Irons (Nov 3, 2009)

HTPatch said:


> It may be very similar to the Eddy current effect you get when you drop a magnet down a copper tube. It slows down the rate of speed.
> 
> Tom



Same effect. Low frequency transformer cores are laminated to mitigate the negative effects of eddy currents.


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## stihl88 (Nov 3, 2009)

Flight time is roughly 2 minutes, just enough time to do a few laps. Unfortunately by using Infrared Receivers limits where the plane can be flown, flying it outside usually doesn't work due to the UV rays knocking out the signals emitted by the transmitter but usually something so light isn't the best idea to fly outside due to the small drafts of wind etc... But in order to go the lightest then you must use receivers that are Infrared unfortunately.

If your really interested in the light weight stuff then take a look at some of these world record breakers: http://www.rcgroups.com/forums/showthread.php?t=597279

This is currently the lightest RC plane known: http://www.rcgroups.com/forums/showthread.php?t=961876
I could come close to building a plane this size as i have all the equipment and skill to do it but theres just too much frustration involved with building something that's nearly 1/10th the weight of a TISSUE :shock:


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## goldmelts (Nov 11, 2009)

I heard it's something called magnetic drag.

It's related to magnetism and movement

The example I saw was, a non magnetic wheel spinning fast. =f you try to hit it with a magnet (think of a hammer but with a magnetic head not iron), it repells from the spinnign wheel.

funny..

So if you drap a strong magnet across a Ag bar, you can feel the drag. Haven't tried this with a AU bar, since It's too expensive.


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## stihl88 (Nov 11, 2009)

Goldmelts, i just edited the title and added SILVER bullion, i wish it were AU :mrgreen:


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