# What are these made of?



## ilyaz (Jun 19, 2011)

Took apart some ancient computers including some harddrives. The platters that came from these are of two types (see photo). The one on the left looks just like a "regular" platter, the one on the right has this reddish color. Both are 5 1/8" in diameter with a 1 1/2" hole and are 1/16" thick.

Are these any more/less valuable that newer platters? That is, are they also aluminum with possibly some tiny amounts of platinum?

Thanks!


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## rusty (Jun 19, 2011)

Have you tested it with stannous chloride,,,, Have you read hokes book on refining precious metals of her companion book testing precious metals. Both books are available on-line - free.

What you have is Iron oxide on aluminum platter, many threads already exist on the forum covering this topic.

Regards
Rusty


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## Claudie (Jun 19, 2011)

Some of the older ones are glass.


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## silversaddle1 (Jun 19, 2011)

Claudie said:


> Some of the older ones are glass.



Most of the newer ones are glass.


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## rusty (Jun 19, 2011)

silversaddle1 said:


> Claudie said:
> 
> 
> > Some of the older ones are glass.
> ...



Good point silversaddle the newer glass platters pound for pound be worth less, scrap aluminum is worth much more than scrap glass.

Regards
Rusty


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## ilyaz (Jun 20, 2011)

silversaddle1 said:


> Claudie said:
> 
> 
> > Some of the older ones are glass.
> ...



Didn't know that, thanks.

Interestingly, http://en.wikipedia.org/wiki/Hard_disk_platters does not even mention platinum


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## Claudie (Jun 20, 2011)

I think I remember reading about a test of these. As I remember it, some did have minute amounts of platinum but so small amounts that it would take several to be worth doing. There are a lot more that do not contain PMs than those that do. Now if you figure out a fast, inexpensive way to tell the platinum ones from the others, you may be onto something. I think (I may be wrong) lazersteve did the testing. Try doing a search of his posts for platinum hard disks.


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## patnor1011 (Jun 20, 2011)

Lets finally bury this platinum from hard-drive platters nonsense. There is tens of times more value in aluminum in them. Minute traces of Platinum are not worth to go after maybe only if you will have several tons of them. They are good for one thing - part fool with his money on ebay. Maybe for making decorative items. You will make several times more selling them as aluminum than trying to extract Platinum from them.


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## ilyaz (Jun 21, 2011)

patnor1011 said:


> Lets finally bury this platinum from hard-drive platters nonsense. There is tens of times more value in aluminum in them. Minute traces of Platinum are not worth to go after maybe only if you will have several tons of them. They are good for one thing - part fool with his money on ebay. Maybe for making decorative items. You will make several times more selling them as aluminum than trying to extract Platinum from them.



If I can sell them as alum scrap, I'll be happy! I am not trying to get rich off of platinum recovery, I am just trying to get as much value as I can from these disks that are taking up some space in my basement.

By the way, I was taking apart another drive yesterday and at some point applied some force to one of the platters. It bent. Now, conventional wisdom tells me that glass does not bend but aluminum might. Now, do I have to apply some non-conventional wisdom, or did I find a simple way of figuring out what a platter is made of?


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## macfixer01 (Jun 21, 2011)

ilyaz said:


> patnor1011 said:
> 
> 
> > Lets finally bury this platinum from hard-drive platters nonsense. There is tens of times more value in aluminum in them. Minute traces of Platinum are not worth to go after maybe only if you will have several tons of them. They are good for one thing - part fool with his money on ebay. Maybe for making decorative items. You will make several times more selling them as aluminum than trying to extract Platinum from them.
> ...




Well as a crude test you could scrape away a small spot of the magnetic coating and apply a drop of some common lye (sodium hydroxide dissolved in water), to the bare metal. Lye will attack aluminum and bubble off hydrogen. The same thing would happen with certain other metals like magnesium, but you would never find that in hard drive platters anyway.


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## patnor1011 (Jun 21, 2011)

If you want to find if they are aluminum or glass simply drop them on floor. That is how you can apply your conventional wisdom. Any broken glass can be disposed in glass banks.

This is what hdd platters are good for:
http://www.google.ie/search?hl=en&q=wind%20chimes%20from%20hard%20drive&gs_sm=e&gs_upl=1418l10201l0l18l18l0l3l3l0l213l2239l3.11.1l15&bav=on.2,or.r_gc.r_pw.&biw=1138&bih=535&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi


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## Claudie (Jun 21, 2011)

patnor1011 said:


> If you want to find if they are aluminum or glass simply drop them on floor. That is how you can apply your conventional wisdom. Any broken glass can be disposed in glass banks.
> 
> This is what hdd platters are good for:
> http://www.google.ie/search?hl=en&q=wind%20chimes%20from%20hard%20drive&gs_sm=e&gs_upl=1418l10201l0l18l18l0l3l3l0l213l2239l3.11.1l15&bav=on.2,or.r_gc.r_pw.&biw=1138&bih=535&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi



Sometimes they don't break that way, they bounce....


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## joem (Jun 21, 2011)

Claudie said:


> patnor1011 said:
> 
> 
> > If you want to find if they are aluminum or glass simply drop them on floor. That is how you can apply your conventional wisdom. Any broken glass can be disposed in glass banks.
> ...



Hammer time


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## Militoy (Jun 21, 2011)

joem said:


> Hammer time



That's not a "hammer" - it's a "high-speed disk-test device"!


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## Harold_V (Jun 22, 2011)

ilyaz said:


> Now, conventional wisdom tells me that glass does not bend but aluminum might. Now, do I have to apply some non-conventional wisdom, or did I find a simple way of figuring out what a platter is made of?


A file is your friend. Aluminum is a rather white metal, almost as white as silver. With the corner of a file, file a notch in the disc. If it's glass, you won't see the metallic luster of aluminum. 
A conclusive test would be a drop of HCl, which readily dissolves aluminum. You'll witness evolution of bubbles and vapors. Nitric acid does not dissolve aluminum. 

Harold


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