Fire Piston

[Jack Russell]

"release vacuum valve" Wassat?[/QUOTE]

Right then let's see. The piston you have made is what is now termed "first generation" - the piston rod compresses air at the bottom of the chamber and bounces back a little after the stroke. When not in use the rod can come out of the chamber (unless you design in a retainer clip of some sort). "second generation" pistons have an air release screw at the bottom of the chamber which can be opened allowing the piston rod to travel all the way to the bottom of the cylinder then closed to make the cylinder airtight again. When this is done you create a vacuum which will hold the piston rod inside the chamber (if you pull on it, it gets sucked back to the bottom). Now, because I live and play in a sand/salt environment the advantage is that a lubricated piston rod doesn't get contaminated as it's captive in the chamber. Check out the wilderness solutions ones on Amazon (seriously posh so don't mention them to Martin cos they're shiny and VERY expensive) or look them up on fleabay (a guy called walleringbear stocks them and there's a linky for a demo video on youtube in his sales blurb). I still do first generation pistons for all the surf bums and dune hobo's cos they are quick builds but a second generation adds a nice challenge to the project if you've mastered the basics.

[jbrown14]

I'm watching this thread with interest. It's a nice job you did there.

What kind of wood is it? There are some lovely colors in it!

[Metal mug]

If I made a fire piston out of wood it'd probably catch fire.

[Bernie]

I'm watching this thread with interest. It's a nice job you did there.

What kind of wood is it? There are some lovely colors in it!

Thank you very much jbrown. The wood is Yew. I have a fair bit of it so it seemed suitable. It's fine grained and finishes very smooth if cut well. It has very pale sapwood and heart wood ranging from amber to deep red, even purple at times. Yew will carry the iron from nails up through the tree which both colours the wood and helps make tools blunt very quickly. Over time (a long time), exposure to UV light will turn Yew a deep brown, and the beauty of it's youth is lost. It's a good lesson for turners to not rely on the beauty of the wood, but to make form and shape that will appeal to the hands and eyes even when the visual appeal has faded.

Yew is poisonous to eat, even the bark. I've heard (I have no proof) that the reason they're often found here in England in church graveyards, is to keep cattle out. I've also heard stories of fallen Yew trees pulling up bones from those graveyards when their roots were drawn out of the soil by strong winds and softened earth. Some people develop an intolerance for the dust which can lead to rashes and breathing problems.

But it is a very pretty wood; there's no doubt of that.

[Edwin]

Would a wooden "pirate" pop gun work? I will try when I can find one we used to have knocking about. Plenty of compression.

[Ashley Cawley]

Beautiful Fire Piston Bernie, I somehow missed this thread first time round, looks great did you ever get it working?

I would say Martin was right about the bouncing-back will be a good indicator of a proper seal for the chamber and compression working.

If it helps here's the video of mine in action, hopefully you'll see a bit of bouncing-back. I intend to use mine more this year