Equipped To Survive Equipped To Survive® Presents
The Survival Forum
Where do you want to go on ETS?

Page 1 of 4 1 2 3 4 >
Topic Options
#183991 - 10/02/09 12:10 PM Signal Mirror durability
damien Offline
Stranger

Registered: 10/01/09
Posts: 13
[censored], or a glass mirror that broke on them?

Ive got a few of the plastic mirrors, and the bags they come in or the plastic protective films they come with seem like mere figleafs - not much protection at all. Same with the glass mirrors - no much protection in the packaging at all.


Top
#183992 - 10/02/09 12:28 PM Re: Signal Mirror durability [Re: damien]
Russ Offline
Geezer

Registered: 06/02/06
Posts: 5357
Loc: SOCAL
I like glass for some applications (flight vest) and a Rescue Flash™ (LEXAN® polycarbonate) Signal Mirror in my backpack. They are stored such that they aren't given the opportunity to get scratched or broken. I wouldn't carry a metal mirror.
_________________________
Better is the Enemy of Good Enough.
Okay, what’s your point??

Top
#183993 - 10/02/09 12:30 PM Re: Signal Mirror durability [Re: damien]
Desperado Offline
Veteran

Registered: 11/01/08
Posts: 1530
Loc: DFW, Texas
First, welcome in.
Second, you see the language sensors already caught something.

I have both types of mirrors, and use the commercially available protective sheets that are designed to protect smart phone screens (specifically iPhone) on all my mirrors.

I have yet to have one scratch, but I have broken a glass mirror in a fit of clumsiness.
_________________________
I do the things that I must, and really regret, are unfortunately necessary.

RIP OBG

Top
#184009 - 10/02/09 02:25 PM Re: Signal Mirror durability [Re: NightHiker]
comms Offline
Veteran

Registered: 07/23/08
Posts: 1502
Loc: Mesa, AZ
I just went to look that the signal mirror in my EDC, its a Coghlans #9900 signal mirror. Cracked. Along the back with three veins. Mirror itself is fine. Probably put some duct tape or clear vinyl tape over the back till I replace it.

I'll weigh it out and look for a lighter replacement.
_________________________
Don't just survive. Thrive.

Top
#184026 - 10/02/09 04:34 PM Re: Signal Mirror durability [Re: comms]
TeacherRO Offline
Carpal Tunnel

Registered: 03/11/05
Posts: 2574
Have one in my hiking/ biking kit for 5 years in - will go take a look at it.

Top
#184034 - 10/02/09 06:03 PM Re: Signal Mirror durability [Re: TeacherRO]
Susan Offline
Geezer

Registered: 01/21/04
Posts: 5163
Loc: W. WA
Is there any real difference for survival purposes in first-surface (reflective coating on the front) and second-surface mirrors (reflective coating behind the glass)?

I am surprised that Corning, with all its experience in glass and ceramics hasn't come out with something useful, highly reflective, and unbreakable (or nearly so). They do so much for optics and space materials that one might think they would have something, and we just haven't heard about it.

Sue

Top
#184055 - 10/02/09 09:46 PM Re: Signal Mirror durability [Re: Susan]
NobodySpecial Offline
Member

Registered: 03/03/09
Posts: 197
"vacuum desposited mineralization" means an aluminium coating evaporated onto it - since that's the standard way of making a mirror for about the last 80years that's not too surprising.

You can put a coating on the front of a surface - the advantage then is that the base material doesn't have to be transparent. But it is liable to get scratched.

Or you can coat the back of a transparent material. This is how almost all mirrors are made unless you work in an optics lab. The disadvantage is that a small amount of light (6-7%) reflects off the front surface - which doesn't matter for a rescue mirror since it's going in the same direction as the main light.
The advantage is that the mirror surface is sealed and so can't scratch. If the seal is airtight the reflectivity is higher than for a front surface mirror since aluminium drops to about 60-70% reflectivity on contact with air.

The advantage of a glass mirror is that it can be made stiffer and flatter than plastics. Any surface error or overall curvature spreads the beam out and so reduces the power that hits the eyeball of the observer.


ps. Yes that is how you spell aluminium


Edited by NobodySpecial (10/04/09 01:28 AM)

Top
#184057 - 10/02/09 09:51 PM Re: Signal Mirror durability [Re: NobodySpecial]
Hookpunch Offline
Member

Registered: 06/11/07
Posts: 128

Buy 2, one to practice with and one that you keep safely stored and unopened in the package in your emergency kit.

Top
#184097 - 10/03/09 12:36 AM Re: Signal Mirror durability [Re: NobodySpecial]
Compugeek Offline
Enthusiast

Registered: 08/09/09
Posts: 392
Loc: San Diego, CA
Originally Posted By: NobodySpecial
"vacuum desposited mineralization" means an aluminium coating evaporated onto it - since that's the standard way of making a mirror for about the last 80years that's not too surprising.

You can put a coating on the front of a surface - the advantage then is that the base material doesn't have to be transparent. But it is liable to get scratched.

Or you can coat the back of a transparent material. This is how almost all mirrors are made unless you work in an optics lab. The disadvantage is that a small amount of light (6-7%) reflects off the front surface - which doesn't matter for a rescue mirror since it's going in the same direction as the main light.

<snip>

ps. Yes that is how you spell alumunium
[pedant]More accurately, that's ONE way, "aluminum" being the more common way, at least in the US. smile [/pedant]

There's also a tiny loss to transmission through whatever the substrate is, but it's truly insignificant in this situation. As you mentioned, a good quality seal between the coating and the substrate more than makes up for it.
_________________________
Okey-dokey. What's plan B?

Top
#184280 - 10/05/09 12:01 AM Re: Signal Mirror durability [Re: damien]
SCKAUTOCRAFT Offline
Stranger

Registered: 09/18/09
Posts: 10
I have kept an ACR signal mirror on my boat for at least 5 years, and it looks as clear as the day it came out of the package. It is kept in a cubby hole at the helm,just siting, no case. CountyComm offers a nice one that comes with a nice case.

Top
Page 1 of 4 1 2 3 4 >



Moderator:  Alan_Romania, Blast, cliff, Hikin_Jim 
March
Su M Tu W Th F Sa
1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31
Who's Online
0 registered (), 269 Guests and 21 Spiders online.
Key: Admin, Global Mod, Mod
Newest Members
GallenR, Jeebo, NicholasMarshall, Yadav, BenFoakes
5367 Registered Users
Newest Posts
What did you do today to prepare?
by dougwalkabout
Yesterday at 11:21 PM
Zippo Butane Inserts
by dougwalkabout
Yesterday at 11:11 PM
Question about a "Backyard Mutitool"
by Ren
03/17/24 01:00 AM
Problem in my WhatsApp configuration
by Chisel
03/09/24 01:55 PM
New Madrid Seismic Zone
by Jeanette_Isabelle
03/04/24 02:44 PM
EDC Reduction
by EchoingLaugh
03/02/24 04:12 PM
Using a Compass Without a Map
by KenK
02/28/24 12:22 AM
Newest Images
Tiny knife / wrench
Handmade knives
2"x2" Glass Signal Mirror, Retroreflective Mesh
Trade School Tool Kit
My Pocket Kit
Glossary
Test

WARNING & DISCLAIMER: SELECT AND USE OUTDOORS AND SURVIVAL EQUIPMENT, SUPPLIES AND TECHNIQUES AT YOUR OWN RISK. Information posted on this forum is not reviewed for accuracy and may not be reliable, use at your own risk. Please review the full WARNING & DISCLAIMER about information on this site.