Suitable magnifying glass for fire starting?

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WittyUsername

Tenderfoot
Oct 21, 2020
89
24
35
Kent
Hi, has anyone got a magnifying glass they’d recommend for fire starting? I’ve read that it’s very easy with some strength lenses and almost impossible with others.

Any tried and tested ones you guys can recommend for my fire starting kit?

Cheers.
 

gra_farmer

Settler
Mar 29, 2016
556
307
Kent
Get a jewellers loupe, compact, metal and cheap, about £3. instant fire with one of these.....


I use also use an old projector lens, and that is amazing
 
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Nice65

Full Member
Apr 16, 2009
4,985
1,540
W.Sussex
Get a jewellers loupe, compact, metal and cheap. instant fire with one of these.....


Strangely, I was going to say I’ve a 20x and never managed to even make a burn on the garden table with it. It’s narrower than 21mm, I don’t think it gets the light through it. When I was a kid much of our fun was lenses, magnets, and dodgy chemical sets, I’ve always been fascinated by lenses.

What I’d like to have a look at is the domes I see inside car modern headlights to focus the LED to a tight beam. Not that it’s very portable or particularly relevant to the OPs question. What won’t work, I think, is a narrow aperture.
 

Billy-o

Native
Apr 19, 2018
1,584
676
Canada
A 10x or perhaps better a combo loupe with an 8x, a 5x and a 3x (there are many variations and numbers of lenses ... they tend to be cheap too). I use a 10x by Bausch and Lomb, but there's a ton of really good cheaper versions .. just not quite so compact. The cheaper ones are fine, but they will distort and give colour separation at the edges, often.

Keep the thing about you for inspecting bugs. Attach it to a Victorinox Compact or another SAK like a Huntsman (one with a saw) plus a pair of Sliver Grippers for digging out splinters and the like. Add small nailclippers (by now you are looking at a keyring to hold this stuff), a little fauxton plus one of those little clips for attaching to another keyring or whatever, and you have a very handy item for the outdoors.

I often can't get a 20x to work even for just looking through. They need lots of light to get the subject well enough illuminated.
 
Last edited:

gra_farmer

Settler
Mar 29, 2016
556
307
Kent
Strangely, I was going to say I’ve a 20x and never managed to even make a burn on the garden table with it. It’s narrower than 21mm, I don’t think it gets the light through it. When I was a kid much of our fun was lenses, magnets, and dodgy chemical sets, I’ve always been fascinated by lenses.

What I’d like to have a look at is the domes I see inside car modern headlights to focus the LED to a tight beam. Not that it’s very portable or particularly relevant to the OPs question. What won’t work, I think, is a narrow aperture.
I have found the 30x and 40x loops work a treat, plus those are what I had to hand. Noon overhead sun is best, for results, but really the old projector lens are the best, as they have a larger surface area.

I really like the idea of the headlamps, so are going to be breaking some headlights of locals to try it.....:)
 
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C_Claycomb

Mod
Mod
Oct 6, 2003
6,078
1,094
Bedfordshire
Learned something! Thanks :)

The only lens I have used is a huge one my dad has had for 40 years for reading small print, about 5" diameter. Not sure of the mag but probably no more than 8x. Still, at that size it always made a crazy hot spot that left a lasting image on the retina if looked at for more than a second.
 

Nice65

Full Member
Apr 16, 2009
4,985
1,540
W.Sussex
I have found the 30x and 40x loops work a treat, plus those are what I had to hand. Noon overhead sun is best, for results, but really the old projector lens are the best, as they have a larger surface area.

I really like the idea of the headlamps, so are going to be breaking some headlights of locals to try it.....:)

The best for fire starting Ive found is a big and powerful magnifying glass, what you say about surface area of the lens seems right. I don’t think I could start a fire with a rifle scope, however well it concentrates its focus, just as I can’t with a small loupe.

Perhaps not the locals headlights despite the plush Landrovers that abound, it’s all chainsaws, tree surgeons and sawmills round here, most of them mates :). I might try the local breakers yard though. It’s one of those things that’ll be the first to break even in a minor shunt and involve replacing the whole headlamp unit. There must be hundreds of them about being chucked away. I’ve no idea what that lens bit is even called to be honest, they just intrigue me.

Edit: They are called projection modules says google.
 
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gra_farmer

Settler
Mar 29, 2016
556
307
Kent
The best for fire starting Ive found is a big and powerful magnifying glass, what you say about surface area of the lens seems right. I don’t think I could start a fire with a rifle scope, however well it concentrates its focus, just as I can’t with a small loupe.

Perhaps not the locals headlights despite the plush Landrovers that abound, it’s all chainsaws, tree surgeons and sawmills round here, most of them mates :). I might try the local breakers yard though. It’s one of those things that’ll be the first to break even in a minor shunt and involve replacing the whole headlamp unit. There must be hundreds of them about being chucked away. I’ve no idea what that lens bit is even called to be honest, they just intrigue me.

Edit: They are called projection modules says google.
Sounds like you have a project Rich, interested to hear about your findings...
 

WittyUsername

Tenderfoot
Oct 21, 2020
89
24
35
Kent
Cheers everyone. It’s difficult to find a 40x magnification lens that’s 3-5” in diameter, and I’d like one that’s as effective as possible as we rarely get a full, sunny day.
 

Allans865

Full Member
Nov 17, 2016
293
62
East Kilbride
This is the one that lives in my firefighting kit, and gives an instant crazy hotspot on anything you focus it on, especially darker coloured items


ATB,

Allan

Sent from my SM-G973F using Tapatalk
 
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WittyUsername

Tenderfoot
Oct 21, 2020
89
24
35
Kent
This is the one that lives in my firefighting kit, and gives an instant crazy hotspot on anything you focus it on, especially darker coloured items


ATB,

Allan

Sent from my SM-G973F using Tapatalk

Perfect, cheers mate. I found an identical one on Amazon if anyone else is interested...

 
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Allans865

Full Member
Nov 17, 2016
293
62
East Kilbride
Perfect, cheers mate. I found an identical one on Amazon if anyone else is interested...

No worries mate, glad to have helped

Sent from my SM-G973F using Tapatalk
 
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Billy-o

Native
Apr 19, 2018
1,584
676
Canada
Might see if I can find myself one of them :). Wonder if you can get them so that they fold away into a handle.

Btw ... you've possibly got a magnifying glass in the baseplate of your compass.
 

WittyUsername

Tenderfoot
Oct 21, 2020
89
24
35
Kent
Get a Fresnel lens cheep/light weight/large and small or cut down a large one to fit size wise where you want...

I read that you need really intense sun for those to work. Is that wrong? I’ll definitely get one if you guys have tried and tested them.
 

Nomad666

Member
Nov 6, 2015
25
4
BC Canada
I find they work just as good as any lens does maybe even better I use a sheet 8x11 inches and it really works like crazy I have some as small as credit card size and they also work great...
they are so thin you can always find someplace to slip it in the large ones I have at the back of my haversack and in the pocket for the water bladder I forget half the time I even have it with me when its in its hidey spot...
They cost under 2 dollars here at the dollar stores...
 

WittyUsername

Tenderfoot
Oct 21, 2020
89
24
35
Kent
I find they work just as good as any lens does maybe even better I use a sheet 8x11 inches and it really works like crazy I have some as small as credit card size and they also work great...
they are so thin you can always find someplace to slip it in the large ones I have at the back of my haversack and in the pocket for the water bladder I forget half the time I even have it with me when its in its hidey spot...
They cost under 2 dollars here at the dollar stores...

Thanks mate, I’ll get a couple and try them then.
 

Rabbit leg

Forager
Nov 9, 2016
117
59
UK and world
Some above have already mentioned but just want to clear it up -

Magnification has nothing to do with it. A jeweler's loupe is not a good choice.
A larger diameter lens collects more light/photons and is therefore more powerful.
 
i'm not using any modern methods for fire starting at all, so magnifying glasses are an important part of my kit. bi-convex lenses seen to work better and about 2" diameter is my normal pocket carry. i also had a Fresnel lens ca. credit card size which worked well even on a clear winter day in central europe until my buddy's mom mistook it for a piece of plastic garbage

2 small tricks for greater success i came up with are #1: dark colours and black attract heat so some charcoal powder sprinkled on your tinder or charcoal/ pencil rubbed onto it helps in less-than-perfect sunlight
#2: put something smooth (dry leaf/bark) on fluffy or loose tinder (like sawdust or dry crumbled up kangaroo poo) to create a smooth surface and let the sunlight "burn through"
 

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