Struggling with hard drives - Page 2

Originally Posted by eesakiwi

What happens of you microwave them?
Works for CD's.......

That's a film sprayed over the alum platter, you know what happens when you put metal in a microwave??
Smoke and fire,,, Rumor has it that is a platinum layer sprayed on them, have heard yes and no on that deal but have not found the proof one way or the other. Here is one explanation;

It's taken me just about forever, but I've finally found some way to answer the simple question "How much platinum is in these hard drive platters showing up on Ebay for salvage?" "The Chemistry of Computing" over at extremetech.com (article2/0,2845,1946290,00.asp) has all the facts: surface layer of Co-Cr-Pt alloy is 40-50% platinum, and the layer is ~30 nm thick. I don't have a hard drive platter in front of me, so let's just forget about the hole in the middle for a moment, so one platter from a 3.5" disk is 3.14*(3.5/2)^2=10.4 sq inches or 67.2 cm^2 ... times the 30 nm thickness (3x10^-6 cm) is 2.0x10-4 cm^3, times the (optimistic) 50% Pd, times the density of Pt (21.45 g/cm^3) and I estimate one platter has at most 2.2 mg Pt. As of 08/29/2008, the platinum spot price was 1470.00 USD per troy ounce, or more usefully, 4.73 cents per miligram. So, congratulations, you've just spent an hour of time and three cents of chemicals (just a guess, probably high) to reclaim 10 cents of platinum, probably still contaminated with cobalt and chromium depending on your recovery method. I hope you bought a whole bunch of platters cheap and rode a bike to pick them up because I doubt you'll be paying for gas let alone the shipping with the platinum. Or hope those early hard drives used a much thicker layer....
Read more: http://wiki.answers.com/Q/How_much_p...#ixzz1vZkPwrmj

I thought about how to scrap the hard drives last night.

Can you drill a hole into the side of the case thru the ali & into the side of the discs, that should also rip up the disc making it useless.
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A while ago I got a harddrive disc & scratched across it & put that into a container with HCL acid.
It ate all of the Ali inside the disc & left a suprisenly thick coating that the acid didn't affect.
I have used HCL acid to eat up chrome/nickel heater elements before so I don't expect the outer layer to contain chrome or nickel. I don't have the weight or thickness at the moment.

Originally Posted by eesakiwi

The outer layer of the disc, after the HCL acid had eaten out the inner aluminum layer weighed 1.4 gramms.

What did that leave you with? Mike.