This lesson is on how to make a unique fire making tool called a Fire Piston. It ignites a small piece of tinder by rapid compression/depression of air inside of a cylinder. When used correctly, it can produce an ember in under a second. It can be a useful tool and a fun way to demonstrate a few scientific principals.
⦁ 6in piece of 1/2in Aluminum tubing
⦁ 7in piece of 3/8in Aluminum Solid Rod
⦁ Resin
⦁ Small O-ring
⦁ Mold making materials
Here is the full layout for the process
⦁ Cut a 6 inch section out of the tubing AND rod. A drill and a hacksaw make for fun and fast cutting.
⦁ Score the end of the solid rod about ½ inch from the tip. This is where the O-Ring will go. The same drill/hacksaw technique works really well to evenly score the rod. Score it deep enough so that the rod and O-Ring will just barely fit in the 1/2in tubing. Lightly sand one end of the tubing so it does not cut the O-Ring while you are testing it.
⦁ Drill out a small recess to hold the tinder. Do it on the end of the rod that has the O-Ring and drill down about 1/4in and use a size that is just a bit smaller than the 3/8 diameter rod. Sand the end of the rod afterwards to remove and sharpness.
⦁ Now we need a handle for our plunger. I made a mold that allows for two plungers to be cast out of resin. I just set the rod in resin and let cure. You could also drill out wood and shape a wooden handle also. Just glue it in a go. It is important the end of your plunger should reach as close as possible to the bottom of the cylinder so don’t cast more than 1 1/2 inch up the rod.
⦁ Seal the tubing and make it air tight by setting the end in a small amount of resin and let it harden. Let it fill the bottom no more than ½ inch.
⦁ Break off the resin and remove any material on the outside so it is just tubing again with a resin plug still inside. This keeps resin from coming up the tube when we cast the rest in resin.
⦁ Make a mold that will fully encase the tubing in resin when cast. I used a box and piece of wood that was the right shape for what I wanted. A groove at the end was to help with grip when driving the plunger.