How To: Make a Slammin' Fire Piston for Under a Buck

Did you know that there's a way to start a fire by squishing air? In this project, I'll show you how to build a tool that does exactly that—and I'll give you a sneak peak into the principals of how a diesel engine operates!

In the early 1800s, before the invention of the safety match, the "Fire Piston" was a common method of igniting fires. It's rare that you'll see one nowadays, but I built one out of transparent acrylic just for fun, and it makes a nice addition to my emergency kit.

I got these acrylic rods and tubes from a local plastics company that gave them to me for free. They were scraps ready to be thrown out, and perhaps you can find a similar company in your area that will do the same.

You can use a drill press, or handheld drill, to hold and spin the rod, and a hacksaw blade to cut a groove just big enough to fit a small rubber O-ring. Use a drill bit to cut a hole about 1/4" from the O-ring, and cut the rod off at the top of the hole. What you've done is create a claw that will hold your tinder.

Drill and tap the other end of the rod and using a handle, like this one I got from a lawnmower, secure the two together with a hex bolt. Use some of the tubing to reinforce the joint, and add another rubber O-ring to finish the piston.

Glue a scrap piece of acrylic to the base of the tube, and when it sets, grind it down to make it look round. This is mainly for aesthetics. Make sure the joint is completely air tight or it may not work.

The handle of the piston has a cavity large enough to store some tinder, like this char cloth. And I found a cap at the hardware store that fit perfectly to hold it in.

To test it out, add a bit of lubricating jelly like Vaseline to the O-ring, and then some char cloth to the tinder claw, insert the rod gently into the chamber and give it a quick and concentrated whack. You should see the tinder ignite, and then you can transfer it into your tinder bundle and build it up into a flame.

If you hit the piston fast enough, you should get a compression ratio of about 25:1. When the air compresses, the temperature raises to hundreds of degrees Celsius.

That's enough to ignite small tinders.

That's another item for my emergency kit, and a great way to see science in action. And with most fire pistons costing over $40.00, I'm proud that mine does all that and more... and for only a buck.

Haven't see the video yet? You can still see it here!

If you like this project perhaps you'll like some of my others. Check them out at www.thekingofrandom.com