Fire Piston

[TANSTAAFL]

Don't drill a hole larger than 1/4" in diameter, as the larger the hole the more difficult it is to raise the pressure/temperature enough to cause ignition

Actually they can have a larger hole.

For a test rig you can also build one for just a few cents. I made this rig as a first time go.

It is made from 1/2" cpvc pipe with a cap on bottom and a coupling at entry for added strength. Piston is piece of ramrod with a Vaseline lubed o-ring to insure compression. It lights a big chunk of char everytime

 

[TANSTAAFL]

I am curious, what is the history of fire pistons and when did they develop and who used them? It looks like a lot of technology going in here...

As I understand it, they were common amongst the indigenous people of Dutch East Indies. Some say that Rudolf Diesel got his engine thingy idea from the fire piston.
http://www.google.com/search?hl=en&q=rudolf+diesel+fire+piston&btnG=Search

Also Diesel's first attempts at concept engines were made using powdered coal.
http://www.google.com/search?hl=en&q=rudolf+diesel+powdered+coal

 

[TANSTAAFL]

Don't drill a hole larger than 1/4" in diameter, as the larger the hole the more difficult it is to raise the pressure/temperature enough to cause ignition

Actually they can have a larger hole.

For a test rig you can also build one for just a few cents. I made this rig as a first time go.

It is made from 1/2" cpvc pipe with a cap on bottom and a coupling at entry for added strength. Piston is piece of ramrod with a Vaseline lubed o-ring to insure compression. It lights a big chunk of char everytime

I need to correct terminology used and should explain in greater detail.

What I stated as a coupling at entry, is actually a reducing (3/4" to 1/2") bushing. To ease entry of piston o-ring, I used a counter sinking tool (with a water spray) to rough bevel entry hole, followed by a tapered grinding stone, then sanded smooth.

 

[paulvallandigham]

I didn't say you COULDN'T drill a larger hole. I just said it makes it more difficult to get the needed compression to light the tinder.

I don't see any kind of palm rest on your piston. What are you using to drive that stick down into your "cylinder"??? A mallet of some kind? The purpose of a fire piston is to give the primitive hunter a means of making fire without any tools other than his bare hands, and the piston, or what he can gather in the forest.
http://www.firepiston.com/

I have the plexiglass one made by Steve Jeung. I bought it specifically so that others could see that the ember is created inside the piston, and not by some " trick " gimmick. Mine also uses O-rings, rather than braided string and grease. Because of the width of my hands, I cannot simply push the rod in as is shown in the video clip. Instead, I have to bang the handle, or knob of the piston onto something solid while holding the cylinder, to get the needed compression to light the tinder. If I made one for myself, I would make the cylinder larger, and longer, as well as the diameter of the handle or knob to protect my palm.

 

[TANSTAAFL]

I didn't say you COULDN'T drill a larger hole. I just said it makes it more difficult to get the needed compression to light the tinder.

I don't see any kind of palm rest on your piston. What are you using to drive that stick down into your "cylinder"??? A mallet of some kind? The purpose of a fire piston is to give the primitive hunter a means of making fire without any tools other than his bare hands, and the piston, or what he can gather in the forest.
http://www.firepiston.com/

I have the plexiglass one made by Steve Jeung. I bought it specifically so that others could see that the ember is created inside the piston, and not by some " trick " gimmick. Mine also uses O-rings, rather than braided string and grease. Because of the width of my hands, I cannot simply push the rod in as is shown in the video clip. Instead, I have to bang the handle, or knob of the piston onto something solid while holding the cylinder, to get the needed compression to light the tinder. If I made one for myself, I would make the cylinder larger, and longer, as well as the diameter of the handle or knob to protect my palm.

As I stated, this was made up as a cheap way to test the principle, not as something to go afield with. As for how it works, you will note the piston is much longer than the cylinder and is grooved on top for a firm grip, I just place the cylinder on a firm surface, grasp the piston with both hands and rapidly ram it down.



Never underestimate the power of stupid people in large groups