Fire Fog trials

Schuyler and I went down to the Box Shop Thursday night to experiment with the Fire Fog effect I’ve been trying to drum up. We certainly made fire!

fire fog experimentsYes, that’s Schuyler with a Hudson sprayer filled with 87 octane unleaded gas. Don’t try this at home! Aww, do what you want, it’s your home!

Unleaded gas, kerosene, Coleman fuel (white gas), and Smirnoff apple flavored vodka were all underperformers :-(. The unleaded shows these pretty sparkles as if there were iron filing in them. Kerosene burns a little slower, Coleman fuel a touch slower still, and the vodka put the fire out more than it lit it.

In general, spraying makes “a big flame” which is pretty and fun to play with but not what I am shooting for.  We couldn’t get it to reliably make the effect I was looking for. What I’m shooting for:

A 6′ tall, 10′ wide, 10′ long volume is filled with a flammable aerosol. A spark at one end of the volume lights the aerosol on fire. The spectator is able to watch the flame front slowly rip cross the volume. After it cools, another aerosol release and another spark from a different direction lights it up again.

Just once during the night I got what looked close to what I’m aiming for. There was absolutely no wind, I had sprayed a mist more or less in a column over the barrel, the fire caught and ate from the bottom of the mist to the top and over to the left a little :-)
Next tests will involve:

  • paying attention to how heat rises and ignites aerosol above the currently burning volume (maybe make a vertical ignition tube?)
  • testing in a completely wind free environment. The very light breezes blew the fine mist around a lot… and if the droplet size was even smaller, it would blow around even more. Maybe work indoors or in a container or…?
  • smaller droplet sizes with higher pressure? The Hudson sprayer is probably pushing 5-20 psi.
  • try a fogger. I dunno, foggers heat their “fog juice” pretty hot. We don’t want an enflamed fogger.
  • try an ultrasonic fogger (not enough volume of fuel released?)
  • consider using a gas instead of a liquid for the effect. Of course, then it won’t be Fire FOG though.

Charlie showed us this propane in a bottle trick that was pure magic. Stick the head of a propane torch in a clear bottle, the larger the better, he says a 5 gallon carboy is perfect. Turn the gas on to fill the bottle. Then light it. A blue flame rips through the air in absolutely beautiful and delicate ways. We tried with an empty hard  liquor  bottle and it was zowie! So Michael brought out a 5′  x 3″ pyrex tube from his pyrophone. Filling the tube and lighting it was tremendous fun! When on, it would resonate the tube and make music. Or if you put a lot of gas in and then light it, the blue flame would leap through the tube in  fascinating  ways!

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