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

Topic Options
#111383 - 11/04/07 07:02 PM I'm looking for a magnifier for my survival kit
CityBoyGoneCountry Offline
Enthusiast

Registered: 11/04/07
Posts: 369
I want to give myself a variety of options for making fire. I already have a flint and a lighter. Now I'm trying to find a pocket-sized acrylic magnifier (I don't want glass because it might break).

Is there a minimum magnification level you need to start a fire?

Top
#111384 - 11/04/07 07:16 PM Re: I'm looking for a magnifier for my survival ki [Re: CityBoyGoneCountry]
JCWohlschlag Offline
Some guy who wandered in…
Old Hand

Registered: 11/26/06
Posts: 724
Loc: Dallas, Pennsylvania, United S...
Originally Posted By: CityBoyGoneCountry
Is there a minimum magnification level you need to start a fire?

The amount of infrared energy (a.k.a. heat) that can be focused to a point depends mostly upon the surface area of the magnifier lens, not its magnification power. You can have two magnifiers with the same surface area and different powers, and you will have identical results… the only difference is that you will hold one magnifier closer and one farther away when focusing the point of light.

The best bet is to get a good acrylic Fresnel (flat, with the visible concentric rings) magnifier in the biggest size (surface area) that your desired kit will accommodate.
_________________________
“Hiking is just walking where it’s okay to pee. Sometimes old people hike by mistake.” — Demitri Martin

Top
#111389 - 11/04/07 07:48 PM Re: I'm looking for a magnifier for my survival ki [Re: JCWohlschlag]
Alex Offline
Old Hand

Registered: 03/01/07
Posts: 1034
Loc: -
Actually, the higher magnification works better, as far as it's focus length is not too short to burn the lens when tinder ignites. But JCWohlschlag is absolutely correct that the lens diameter (surface area) is a more significant factor.

I'd recommend something not higher than 5x (2 inch focus). The physics behind this is simple. The shorter the focus distance (higher magnification) - the smaller the spot where the energy from the Sun is concentrated (and so higher the temperature).

Top
#111399 - 11/04/07 11:09 PM Re: I'm looking for a magnifier for my survival kit [Re: CityBoyGoneCountry]
Andy Offline
Enthusiast

Registered: 09/13/07
Posts: 378
Loc: SE PA
I have had success buying from these folks 3Dlens .
_________________________
In a crisis one does not rise to one's level of expectations but rather falls to one's level of training.

Top
#111407 - 11/05/07 12:15 AM Re: I'm looking for a magnifier for my survival kit [Re: CityBoyGoneCountry]
CBTENGR Offline
Member

Registered: 06/13/07
Posts: 99
Check these out. They are only a dollar a piece. I have several and they work fairly well. With the case its about the thickness of a credit card.

http://www.bestglide.com/fresnel_lens_firestarter.html
_________________________
Spemque metumque inter dubiis - Hover between hope and fear. (Vergil)

Top
#111430 - 11/05/07 02:04 AM Re: I'm looking for a magnifier for my survival kit [Re: CBTENGR]
Susan Offline
Geezer

Registered: 01/21/04
Posts: 5163
Loc: W. WA
My magnifier is a glass one that swivels into a leather case.

Sue

Top
#111501 - 11/05/07 05:36 PM Re: I'm looking for a magnifier for my survival kit [Re: CityBoyGoneCountry]
Blast Offline
INTERCEPTOR
Carpal Tunnel

Registered: 07/15/02
Posts: 3561
Loc: Spring, Texas
CityBoy,

Wow, a bunch of responses and not one "welcome, newguy!".

So, welcome to the fire newguy!

-Blast, who uses a credit-card sized fresnel lens picked up at a bookstore
_________________________
Blogging the Borderlands
Wild Edibles Blog
I miss OBG.

Top
#111513 - 11/05/07 06:07 PM Re: I'm looking for a magnifier for my survival kit [Re: Blast]
CityBoyGoneCountry Offline
Enthusiast

Registered: 11/04/07
Posts: 369
haha

Thanks for the welcome. Although since I didn't introduce myself either, I guess a welcome was not quite mandatory.

Top
#111524 - 11/05/07 06:57 PM Re: I'm looking for a magnifier for my survival ki [Re: CityBoyGoneCountry]
JCWohlschlag Offline
Some guy who wandered in…
Old Hand

Registered: 11/26/06
Posts: 724
Loc: Dallas, Pennsylvania, United S...
Ah, got caught! I didn’t even notice your post count. Welcome to the forums, newguy!
_________________________
“Hiking is just walking where it’s okay to pee. Sometimes old people hike by mistake.” — Demitri Martin

Top



Moderator:  Alan_Romania, Blast, cliff, Hikin_Jim 
December
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 (), 209 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Newest Members
Acropolis50, SimonBlack88, KnifePark, Sank, AppalachianGirl
5299 Registered Users
Newest Posts
Carrick Loop/ Bowline alternative - Tutorial
by TonyE
Today at 05:04 AM
Article: Community, Preparedness, Resiliency
by DaveL
Today at 02:12 AM
Nifty small headlamp
by haertig
Today at 01:56 AM
Fire starter
by hikermor
Yesterday at 05:11 PM
Happy anniversary to me!
by chaosmagnet
12/06/19 05:53 PM
Farmer's Loop Tutorial
by TonyE
12/04/19 11:08 PM
What's missing- BOB
by teacher
11/30/19 08:01 PM
If You Have to Prep, Do It in Style
by teacher
11/30/19 07:59 PM
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.