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Signal Mirror
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Tony Fischer
(adfischer) - F
MYOG Signal Mirror (Well sorta) on 06/17/2012 18:43:45 MDT Print View

Not exactly sure this counts as MYOG, but since it took some screwdrivers I'll count it as such!

Dont want to argue whether one should carry a mirror. I choose to do so because I like having one for signaling, tick checks, and the occasional personal grooming. I have carried an Adventure Medical signal mirror for a while but I find they scratch easy and do not have a great reflection.

I found a much better option - a platter from a bad hard drive. I pulled two out of a laptop drive recently. They are very reflective and VERY lightweight. This one weighs in at only 4 grams. If you have any bad hard drives laying around, open it up and give it a try.


Edited by adfischer on 06/17/2012 18:44:25 MDT.

Dan Yeruski
(zelph) - MLife

Re: MYOG Signal Mirror (Well sorta) on 06/18/2012 10:22:21 MDT Print View

What material is it made of and if it's plastic will it scratch easily as your of the shelf signal mirror? try scratching both to compare. Thanks for the tip.

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Re: MYOG Signal Mirror (Well sorta) on 06/18/2012 11:01:09 MDT Print View

Yes, great tip!

I was skeptical at first because I like the "sighting" center on the typical signal mirror but was pleased to find that the hole in the platter serves the same function.

By looking through the hole and reflecting the sun onto the first finger of my other extended hand I can quickly place the "shadow" created by the hole on the tip of the finger. Then by moving slowly to keep things centered, if I place that finger tip on the target I get excellent alignment, even at very oblique angles.


Edited by greg23 on 06/18/2012 17:07:53 MDT.

Roger Dodger
(RogerDodger) - F

Locale: Wess Siide
Re: MYOG Signal Mirror (Well sorta) on 06/18/2012 11:17:48 MDT Print View

+1 to Tony.

at various evolutions, my kit has a similar setup with an blank CD that is silver shiny on both sides. Part of my kit is to include a lanyard through the center hole, for example to hang the reflective mirror around my neck, or the outside of my backpack, or to hang off a sunny tree branch twirling in the breeze to strobe signal for help.

Other elaborate combinations would be to use the LED headlamp strobe blink features to reflect off the disc, to double to signaling potential at night.

My CD cracked and started to separate layers after 5 years of being stored in my "oh_ śh . ĩt _kit" never got to use it, neither for fun or for emergency - lucky I suppose.

A lot safer than starting a forest fire to get rescue attention - which is the popular approach these days in the San Bernardino National Forest, according to the rescue volunteers.

This is repurposing old technology trash, and giving it a second life and a second purpose, without having to buy an expensive gadget that does the same function.

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Re: MYOG Signal Mirror (Well sorta) on 06/18/2012 12:31:28 MDT Print View

I just did a quick and dirty comparison between a CD and a hard drive platter. The CD doesn't even come close.

My "target" was the center of a shaded porch about 50 yards away. It was nearly impossible to see the reflection created by the CD. The image from the hard drive platter was very well defined.

It will take a two person team with radios to perform a long distance test - greater than 1000 yards - but I am pretty confident how the CD will fare. (It will be interesting to see how the hard drive platter compares to a signal mirror.)

And this is understandable: the CD is a 2nd surface device with very little attention to flatness. A hard drive platter is the opposite: first surface and Very flat.

Roger Dodger
(RogerDodger) - F

Locale: Wess Siide
Re: Re: Re: MYOG Signal Mirror (Well sorta) on 06/18/2012 14:03:25 MDT Print View

I agree Greg. That old computer in the corner of the room under the pile of junk, it doesn't know it yet, but it is in for a surprise. :)

I also have an old compact mirror from my wife's old makeup stuff, haven't measured yet, but I think that the hard drive platter is lighter than a glass mirror in a plastic case.

Dave Heiss
(DaveHeiss) - M

Locale: Pacific Northwest
Hard drive platter as signal mirror on 06/18/2012 14:51:50 MDT Print View


Have you noticed any oxidation or discolorations yet on the hard drive platter? I know there are ferrous materials used in hard drive construction and I'm wondering if (and for how long) yours will stay bright now that it's out of the casing.

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Hard drive platter as signal mirror on 06/18/2012 17:05:03 MDT Print View

I've had a hard drive platter sitting out for at least 6 years and it looks like new.

Tony Fischer
(adfischer) - F
Platter on 06/18/2012 20:28:26 MDT Print View

The one I showed in the picture has been open sitting in my bookcase for at least 5 years with no signs of oxidation.

One other comment I would make is some platters are made of glass, others metal. I would be sure it is not made of glass. You should get a metallic sound when you gently strike it if it is metal. I would not pack a glass one for obvious reasons.

Joel Hulett
(jhalan) - F

Locale: Midwest
Disc composition on 06/19/2012 13:13:39 MDT Print View

The hard drives of old used to be made out of pure platinum. They are hard to find as they were quickly recycled. The new generation, for those less geek minded, are platinum plated aluminum. Lighter and faster than the old drives. If the surface platinum is not penetrated it will stay shiny for a very very very very long time. Platinum, like titanium is very chemicaly inert. Not edited for spelling sorry.
Excellent repurpose btw

Edited by jhalan on 06/19/2012 13:19:10 MDT.

David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Re: Re: MYOG Signal Mirror (Well sorta) on 06/19/2012 14:00:52 MDT Print View

+1 to Tony.

> my kit has a similar setup with an blank CD that is silver shiny on both sides.

Roger: since it is reflective on both sides, you can multi-task by shaving while signaling your rescuers?

Roger Dodger
(RogerDodger) - F

Locale: Wess Siide
Re: Re: Re: MYOG Signal Mirror (Well sorta) on 06/19/2012 14:52:18 MDT Print View


:) Multi-use gear, cuz we gotta look good for the news camera crew, when getting rescued.

a clip from a fav Bruce Lee movie: