How to Start a Fire With Glasses (Convex Lenses Only)

Fire is one of the most important things you can have in a survival situation. While using matches or a lighter is the easiest way to start a fire, you can also use convex lenses from your glasses.

Although there’s a bit of a learning curve, anyone can master this skill. So, if you’re willing to learn, this article will teach you everything you need to know about how to start a fire with glasses.

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Why Is It Possible to Start a Fire With Glasses?

Convex lenses, which are the type of lenses used for those who are farsighted, are like magnifying lenses. They help you see things that are very close to you and are commonly referred to as “readers” or reading glasses.

Convex lenses or glasses for farsighted people work by collecting light from the sun and other light sources around you. They then refract this gathered light and bring it into focus.

As a result, the light that’s passing through and getting refracted by the convex lenses has a very high level of energy. By directing this high amount of light and energy at a nearby flammable object, you have enough energy to start a fire.

The process is very similar to how a match uses friction to produce energy and start a flame. The difference is that convex lenses use light as the energy source instead of friction.

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How to Start a Fire With Glasses

Now that you have a better understanding of how the process works let’s dig into the step-by-step process of how to start a fire with glasses.

Choose the Right Glasses

Before you get too excited, it’s important to understand that not all types of glasses can start a fire. You can only use glasses with convex lenses, which are limited to reading glasses or glasses to correct farsightedness, which is when you struggle to focus on things close to you.

Glasses to correct nearsightedness use concave lenses, which have the opposite effect as that of convex lenses. Therefore, if you’re nearsighted, you’re out of luck, but if you’re farsighted, you can use your lenses to learn how to start a fire with glasses.

Use the Sun to Your Advantage

As we said before, you’ll need a source of focused energy to start your fire. Luckily, if you’re in nature, you have access to the most powerful energy source on the planet – the sun.

The sun produces more energy in three minutes than the entire produced energy of the entire world. By focusing the energy from the sun through your convex lenses, you can start a fire.

Gather the Necessary Tinder

However, no matter how much energy you harness, you won’t be able to start a fire without tinder. You can use any form of highly flammable material as tinder, including paper, leaves, grass, cloth, or small, dry twigs.

You’ll need to put your tinder on a pile and ensure that the area is completely dry, or your efforts will be for naught.

Ensure the Conditions Are Right

No matter how good you get at mastering the art of how to start a fire with glasses, you still need the conditions to cooperate. If it’s wet or windy, you’ll struggle to get anything to light on fire.

You’ll also find it impossible to start a fire if the sun isn’t shining. After all, it’s your primary and only source of energy, which makes it just as essential as your convex lenses.

Put It All Together

If the conditions are right, you have your tools and materials, and the sun is shining, you’re ready to learn the step-by-step process for how to start a fire with glasses.

1. Remove your glasses in the midday sun and tilt the lenses toward the sun.
2. Once you catch the sun’s rays in the lens, place your hand underneath the glasses, so the sunlight filtering through them hits your hand.
3. Now, by raising the glasses away from your hand or moving them closer to your hand, you would be able to control the size of the beam of light on your hand. You may need to tilt them a little back and forth, too, to get the best circle.
4. Find the sweet spot and make the smallest, brightest dot you can on your hand. If you do this part right, the magnified sunlight will sting your flesh, and you’ll make that dot so bright that it will hurt you.
5. Be patient here and really learn the process of honing the light to maximize its energy and strength.
6. Once you feel confident in your ability to harness the power of the sun, you can move on to gathering the rest of the materials you need to build a fire and set it all ablaze.
7. Start by gathering nearby tinder to serve as your fire starter. Ensure that everything you use is highly flammable and completely dry.
8. Repeat steps one through four on the pile of tinder until you notice it start to smoke.
9. Stay focused and keep the lenses pointing at the smoking area to intensify the effect. Keep doing this until you notice a tiny flame forming.
10. GENTLY blow on the tinder to provide extra oxygen to the flame, being careful not to blow too hard and extinguish it.
11. Once you’re comfortable that the flame is strong enough, you can slowly add extra tinder and wood to the fire.

Intensify the Magnification if Necessary

Another important aspect of learning how to start a fire with glasses is not giving up. If you’ve been at it for a while and you’re not having any luck, there are a few troubleshooting options you can try.

1. First, rub a little bit of water on the surface of your convex lenses to magnify their strength.
2. If that still isn’t doing the trick, you can use the other lens from your glasses and set it on top of the lens you’re using. This will double the amplification and fire-starting power of your glasses.

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Final Thoughts About How to Start a Fire With Glasses

Persistence, patience, and practice are the three P’s to keep in mind when learning how to start a fire with glasses. If you can master these three disciplines and utilize the information in this article, you’ll be a convex lens fire-starting wizard in no time!

If you’re curious about other creative ways to start fires in survival scenarios, you can find all the information you need in our Fire Starting section