Hard drive platters as bounce mirrors

[blrock]

I was looking at building a new rig with some bounce mirrors. Because I had a number of old hard drives lying about, thought it would be a great idea to strip them as use them in the rig. Spend Saturday morning stripping 6 hard drives.....

Results:

Raw 532nm. Distance 20cm: 550mW
Bounce of hard drive platter . Distance 20cm: 341 mW. Loss 38% !!!!
Front surface mirror. Distance 20cm: 490 mW. Loss 11%
Mirror ball mirror. Distance 20cm. 442 mW. Loss 20%

As you can see very dissapointing results with the platters. So much for a great, cheap alternative front surface mirrors.
Should have done the logical thing as measure the ouput before stipping all the drives

doh!

 

[Lotus_Darkrose]

When I have a hard drive die on me, or replace someones drive and the old one is not useable (and they don't want it back), I always strip it out and take the platters/magnets/spindles. Nice to have someone actually measuring the power loss from bouncing off of one though. Thanks

 

[anselm]

I tried that once and found the reflection off the platter was not a clean dot but rather
a diffraction grating like effect.

 

[blrock]

Those Neodymium magnets are crazy powerful. Caused some injury to my fingers in the past..

I was expecting +-10% loss on the platters.

 

[blrock]

I tried that once and found the reflection off the platter was not a clean dot but rather
a diffraction grating like effect.

I didn't notice that with the small distance I was using...but you 100% correct. The fine tracks on the platter should cause a diffraction effect. Something else I never thought about

 

[Lotus_Darkrose]

The Platters make good personal mirrors though.

I remember posting a long time ago on here about how I followed this instructable and thought it was cool. Things stick in your wall pretty good if made right.
Hard Drive Platter Throwing Star

Also, someone on here said not to do it (when I posted it) because they make good mirrors for lasers. Guess that doesn't apply now haha.

 

[BShanahan14rulz]

be careful, sometimes drive platters are made of glass.

 

[Lotus_Darkrose]

You're working with thin metal and tin snips. Being careful is a given. But yes, I looked that up and some older hard drives (read about laptop drives having them) contain a glass/ceramic substrate instead. Those will shatter.

 

[ITman496]

Oh man do I know about that glass issue. I remember in my class I took apart a desktop hard drive, bent the platter into an arched shape, and made it spin. It was interesting. Then I got a laptop hard drive, went to do the same thing...

The moment I applied the slightest sideways pressure to the platter, it shattered into a million tiny shards everywhere. Everyone in the class couldn't stop laughing as hard drive confetti rained down. lol Nothing a shop vac couldn't fix. Good thing I had goggles on.