The clear air and strong sun of late winter, plus the freezing winter temperatures, give you the best opportunity of the year to pull off the “fire from ice” trick in a real-world scenario. Whether you have seen it in books, or watched it on television, there’s still something incredulous about a lens of ice starting a fire. It just seems so unnatural. And I guess the real question you’re asking is, “does this really work?”
I’m a little surprised by the answer, myself, which is yes, you really can get fire from ice.
But it’s tricky–so difficult, in fact, that I’d truly rather rub two sticks together for fire. For the bold, however, here’s how you can make your own fire from a piece of ice.
First, you’ll need clear ice. I’m not talking about an ice cube from the fridge that you can see light pass through. You need the kind of ice you can see your fingerprint through. Lucky for us, this is achievable out in the field. Ice frozen from precipitation should be relatively mineral-free. Minerals create the cloudiness in your home ice. Precipitation is also free of a lot of dissolved gasses that cloud ice. Find a rain puddle that froze over, or some snow melt that re-froze, and you’re in business. Ice that forms while it’s moving can withstand some mineral and gas impurities while still remaining clear. The ice that forms on the top of a stream is a good candidate for this endeavor.
If you’re trying this at home, buy or make some distilled water. Then boil it for about ten minutes to de-gas the water. Freeze it in a bowl or some other form that will later allow you to carve a bi-convex lens (like a magnifying glass).
The real slippery business begins when you take a sharp knife to whittle away any lumpy spots on the lens. I can’t tell you how many lenses I dropped and broke while working on this post. The lens pictured here was my worst one, but it was also the last one left intact.
You’ll have an easier time working on your lens if the air temperature is below freezing, as melting ice is as slippery as the proverbial greased pig. Each side of the lens has to be perfectly rounded, so that the light will make a proper focal point when it passes through the lens. Use your warm hands for a final polishing of the lens, to melt away any high spots or rough edges.
To use it, treat the lens like a magnifying glass. Focus the sunlight through the lens until it makes a white-hot pinpoint of light. Aim this hot spot onto a piece of char cloth, which will substantially increase your chances of making flame. You can see our post on flint and steel to learn more about char cloth. Be sure to not let any melted ice drip onto your char cloth (that got me once). Once it ignites, put your smoldering char into tinder and blow to create the flame.
Got any tricks for optical fire building? Have you made fire from ice? Take a second to tell us about it in the comments.