Skip to Content

How to Start a Fire with a Magnifying Glass

Starting a fire with a magnifying glass is essential for survivalists or avid outdoorsmen. Why a magnifying glass? It works as an excellent substitute for starting fires in the absence of matches or a lighter. When you’ve exhausted your lighter fuel and matches and your fire steel is worn down, a magnifying glass could be the survival tool used to spark that survival fire.

Sunlight focused through a magnifying glass
Sunlight focused through a magnifying glass

The magnifying glass also takes up very little space in your survival or bug out bag and requires no special tinder except dry fuel sources such as leaves and sticks you can find in the wilderness as needed. You can begin by making your own tinder bundle.

Starting a Fire With a Magnifying Glass

The Sun

When starting a fire with a magnifying, there are certain materials you will want to find or have on hand before you begin. Before you attempt to start your fire, there has to be enough sun in the sky because the sun will generate the heat through the magnifying glass’s concentrated lens. 

Selecting Tinder

Starting a fire with a magnifying  on rocks
Starting a fire with a magnifying glass

Now that you have established the sun is out enough, we will select our tinder. When choosing the tinder, you want to make sure it is dry. Typically, most people use leaves and small branches when starting a traditional campfire with matches or a lighter. When using a magnifying glass, you want to find a more coarse tinder if possible.

Whether you are in a rural or urban environment will also impact what materials you have available. Obviously, in a survival situation, you may not be able to just walk into a store, even in an urban area. If staying out of sight is essential, I have a list below of available tinders in urban or rural areas. As a good rule of thumb in a survival situation, you may want to collect tinder and kindling as you see it, even if it is not needed at the moment. Try to keep a fist-sized ball of tinder in your pocket or survival bag and continually replenish as it gets low. 

  • pocket lint (in a pinch can work)
  • newspaper (tear up pieces and ball it tightly)
  • mail (tear-off clear plastic window and only do in an emergency, it federal offense)
  • cotton balls or cotton on the end of Q-tips
  • pine needles
  • dry leaves
  • shredded, dry pieces of bark balled up tightly
  • dark-colored fabrics or materials work best as they absorb the heat

After choosing which tinder you will use, make sure to have dry sticks and wood close by so once you get it going, you have dry wood to keep the embers fed while you find more wood to keep the fire going. Small sticks and dry leaves work best places on the larger pieces of wood. The smaller sticks and leaves will keep the fire going until the logs are hot enough to stay lit.

Igniting your Tinder

Have a tinder pile ready when you start a fire with a magnifying glass
Have a tinder pile ready when you start a fire with a magnifying glass

Now that you have selected your tinder, you will want to position it in the best way to catch a flame and keep it going. If you are using dried leaves or newspaper, it will need to be tightly balled up or not catch fire. 

We will go with red pine needles as our example. So you will want to make a small tinder pile using thin sticks about the size of a pencil on the bottom. Dry grass makes a great middle layer for the middle layer, but shredded inner bark and birch bark strips work as well. For the top layer of the pile, punk wood works well. Dry, fluffy punk wood is found in old, rotting tree stumps and logs. Make sure it is dry, and you can rub it between your fingers or hands until it is ground up into small pieces with a chunky, powdery feel. Place this on top of the pine needles and grass as the top layer. 

Now that your tinder pile is put together and placed in an area directly in the sunlight, you can get your magnifying glass out. When positioning the magnifying glass, you want it directly in the sunlight. 

When pointing the magnifying glass at the tinder, a few basic rules: never place your hand under the glass while it is in the sun because you will get burnt. 

Once the magnifying glass is under the sun, you will see a small dot appear on the tinder. That is the sun focusing the heat onto that small point. To get the most concentrated heat move the magnifying glass slowly around and up and down from the pile. Leave the magnifying glass in place when you see that dot of light at its smallest point. This is when the sunlight is at its most concentrated point. 

Once it is focused on a specific area, keep that dot of light focused so the heat can build up on the tinder. You know you have a good ember when the tinder ball smokes by itself. This can take several minutes.

Once you have a strong ember, blow on it slightly and add small dry leaves and other quick-burning, small materials to the embers. As the leaves and other materials catch fire on the embers, keep an eye and start to add sticks and larger pieces once you have a small, steady flame. 

Make sure to have plenty of kindling available for your fire going into the night. Magnifying glasses won’t work during the night or on cloudy days, so be prepared for these events and get your fire going early. 

Why it Works

The reason why the magnifying glass works so well in starting fires is the result of photons. Photons are particles that carry visible light from the sun to the earth. Photons have energy in the form of heat, and when they pass through a magnifying glass, heat is concentrated. 

Other glasses will work like eyeglasses or binocular lenses to start a fire. The reason they have the ability is a result of the convex shape of the lenses. This shape collects photons on one side of the lens and draws them to a single point as they enter the other side. So any item with a convex lens can be used to start a fire. The larger the lens, the easier it is to start a fire. The lens is taking in more sunlight, the more significant it is so that more sunlight coming is means more concentrated sunlight going out on the other side.

Magnifying glass and map as survival tools
Pack a magnifying glass with your survival tools

A Great Fire Starting Option

Starting a fire with a magnifying glass is a skill any nature lover, outdoorsmen, or survivalist should have. With the sun, urban or rural gathered tinder, and a magnifying glass you can start a fire for your survival wherever you are. When packing a survival or bug-out bag, a magnifying glass could be a great fire starting item or fire starting back up.