[TheForge] Re: fire piston

[Bob Smolen]

A year or two ago,I was interested in fire pistons. There is a web site that
has a short video of a piston made out of clear plastic. I believe a type of
dried mushroom or some other similar vegetation is used as tinder. The
piston rod is struck and you can see the tinder glow. I was impressed. The
maker uses horn,wood,plastic, to make the pistons. I screwed around a bit
but never got one to work. I did not try very long. The trick is ,I believe,
in the gasket. Too tight and no movement of the ram. Too loose and no
compression.Maybe a slight taper in the cylinder which allows the ram to
start but tightens up deeper in the cylinder.
Natives made large versions from bamboo according to the web site. The guy
with the video sells completed pistons or kits for less $Good luck. .
Bob


----- Original Message ----- 
From: "Demon Buddha" <osan at netlabs.net>
To: <dhayes at dthayes.com>; "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Thursday, June 08, 2006 9:17 PM
Subject: Re: [TheForge] Re: fire piston


>
>
> Daniel T. Hayes wrote:
> > Actually, the "T" in the Ideal Gal Law is absolute temperature (i.e.
Kelvin
> > or Rankine). 70 Farenheit = 528.67 Rankine. Compressed adiabatically
15:1,
> > the air temperature would go up to 7930 Rankine or 7471 Farenheit.
>
> this may be so.  I've not studied the idea gas equations since...well,
> forever.  But remember that real world air isn't an ideal gas.  There
> are losses.
>
> However, my calculations were still off.  It seems the temperature
> should be about 2313*F.  That's pretty amazing.  I'm not sure how you
> got 7471*F, though.  Even with losses I am not sure there would be that
> much difference in temperature.  Adiabatic heat comes solely from the
> effects of compression of the medium (air). Anything at 7400*F would be
> emitting actinic light (e.g. UV).  I suppose this is possible, but it
> doesn't seem right to me.  Could you elaborate?
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