A magnifying glass is great for starting fires. As long as the sun is out! It works best with dry tinder like shaved wood, crunched dry leaves, etc. This article update includes 3 current choices (shown below), any of which you might say is the best magnifying glass for fire starting. Actually, one of them may technically be the best because it’s physically bigger than the other two magnifying glass choices as a fire starter (larger diameter equals more area equals more focused energy. But the other two are great too – and fit better in a survival kit.
A Magnifying Glass For A Fire Starter
I do keep a survival magnifying glass in each one of my kits. That’s along with several other methods to start a fire like a lighter, matches, magnesium fire-starter, Vaseline cotton-ball tinder, and more. Check out the fire starter kit list (article link) at the end…
A magnifying glass will start a fire in seconds. That’s under ideal conditions. How long it takes will vary depending on the time of day, angle of the sun, the efficiency / overall size of the magnifying lens, and the tinder being used.
The quality of the glass (which is often plastic) can make a noticeable difference. The ability to focus a tiny bright spot onto the tinder so as to ignite more quickly.
Can a plastic magnifying glass start a fire? Yes, plastic lenses will work. However some of the cheap ones are simply too poorly manufactured to focus a concentrated beam from the sun. Glass or quality acrylic will be better. Check out my choice for wallet size Fresnel lens in the linked article below.
With that said, most every plastic lens I’ve tested as a ‘survival magnifying glass’ worked. However the following three choices for a fire starter magnifying glass are all real glass.
Does the diameter of the magnifying lens make a difference starting a fire? In my experience, not so much of a difference. Although a larger diameter lens will pick up more available light and is quicker and easier to start a fire.
A word of caution (besides the obvious when making fire) is to avoid looking at the concentrated point of light, which could damage your eyes. It can be very bright! Sunglasses?
How Does A Survival Magnifying Glass Work For Fire Starting
What’s the science behind starting a fire with a magnifying glass? Well, it’s about the photons. Photons are the particles that carry visible light from the sun to the earth. They also contain energy in the form of heat.
Through the use of a magnifying glass, the path of these photons are narrowed to a highly localized area (the dot of light resulting from double convex shaped lens). The focal length is the distance from the lens to where the light is focused. This varies depending on the lens manufacture. The resulting concentration of light / heat can reach incredibly high temperatures. If a high enough temperature is reached (somewhere around 450 degrees F), then tinder or kindling will smolder and begin to burn. Be careful where you focus the light!
3 inch Diameter Double Convex Lens (Optical Glass) Fire Starter
One of my recommendations for a best one, is this magnifying glass. It will certainly serve as a fire starter, especially given its 3″ diameter. You get just the lens, so there’s no handle or other bits to take up space in your kit. However you might want to protect it from scratching – depending where you keep it.
Eisco Labs Lens
(view on amzn)
image from Eisco Labs
The lens has an 8 inch focal length. It gathers lots of light. Optically worked, highly polished glass with ground edges for safe handling.
‘RCH’ said, “A great lens for my fire starter kit. It is big enough to be easily focused. I keep it in a cotton draw string bag wrapped in a micro fiber cloth. Perfect for my use.”
2.4 inch Diameter With Case Protector
Slightly smaller, this one has a nice attached case protector. The lens is glass.
Portable Folding Lens
2 inch Diameter Small Folding Pocket Magnifying Glass
The smallest of the three, this glass is convenient given it’s smaller size. Yes, it will still be effective as a fire starter.
‘Matt’ says, “Small, lightweight addition to a camping pack that allows you to start a fire using the power of the sun (*on bright, sunny days). Convenient case keeps them free from scratches. Also would make a great EDC item for people with poor eyesight.”
[ Read: Fire Starter Kit List ]
[ Read: Fresnel Lens For Your Wallet ]