"If you fail to learn from your mistakes, it's not really science." - Unknown

The Problem

I belong to a group that likes to indulge in camping trips over long weekends twice a year. A central part of that experience is a big campfire. We like a bit of drama, so we apply a light dose of special effects to have the campfire light itself on command.

One year, the fire refused to light itself on schedule. I asked for the job of preparing the next campfire, confident that I could guarantee proper behavior of the fire. The ancients called that "hubris".

This is the story of what happened when I got my turn.

Analysis of the Old Design

I was unable to contact the fellow who had set up the previous fire. All I had to go on was some scraps of information that some other people volunteered and my own observations of previous events.

The old design used ordinary firewood, soaked in common charcoal lighter fluid. Since I had seen no strings and such, I assumed that the ignition was electrical. There had been no fire, smoke, or sound, leading me to believe that the ignition system was at fault.

I concentrated an a "foolproof" ignition system.

Design

Our bonfire was to be built in a large fire pit of stone and concrete.

The body of the fire was of good, dry firewood, obtained commercially in prepackaged bundles. The larger pieces had already been split into quarter-rounds. The fire was carefully laid, log-cabin style, with plenty of gaps for draft. The center of the pile was hollow, forming a sort of chimney. The top was covered with a row of small sticks, presenting a surface that was flat like the top of a rough table.

Just before the campfire was to begin, a generous amount of commercial charcoal lighter fluid was to be poured over the wood.

The igniters were nestled in the bottom, with triggering lines leading out of the fire pit and disguised.

In order to guarantee ignition, three different igniters were constructed. Each one used a different design, in hopes that any design defects that were present {in one design} would not {be present in different designs to} shut down the show.

The primary igniter was mechanical, being activated with a pull string. It contained little pyrotechnic material and a moderate amount of kindling, intended to be moistened with the same liquid fuel that would be used to help the wood catch fire rapidly. The string headed to the place where the Master of Ceremonies would be standing; he was to shoot the bonfire when he was ready. I had built several of the mechanical igniters and they had all worked as intended.

The secondary igniter was electrical. It consisted of an electric match and a small pyrotechnic booster charge. It, too, relied upon kindling dampened with liquid fuel. I had also tried several samples of this design with no failures.

The final option was a large affair, a pyramid roughly six inches tall. It leveraged off of commercial pyrotechnic material, in quantity, to be started with two electric matches in parallel. There was nothing subtle about it. It was untested, but of such brute force that it "couldn't" fail.

In order to insure that there was no single point of failure, the two electrical igniters were attached to completely different firing systems with independent wiring, batteries, firing switches, and safety mechanisms.

The Shoot

The bonfire was prepared well in advance. Just before the evening activities started, the wood was doused with liquid fuel.

The opening festivities took an extraordinarily long time.

Eventually, it was time for the fire. The Master of Ceremonies stepped forward and picked up the string for the mechanical igniter. He gave it a tug. There was a wisp of smoke and a small brief flickering of light, and then the fire pit was quiet again.

I reached under my bench and flipped a safety switch and then pressed a button. There was a crackling sound, a little smoke, a little light, and then silence again.

Once more, I reached under the bench. I flipped the second safety switch and held the second firing button down for a long time. There was a brief spurting noise and a tiny puff of smoke.

It seemed as if I had struck three times and was out of the ball game.

I had a fourth igniter: a large box of "lifeboat" matches that burn hot and long. I was just getting ready to stand up and walk over to the fire to light the silly thing myself, when I noticed that the smoke was still gently puffing.

The wispy smoke was soon accompanied by a bit of red light that shone from between the gaps in the pile of wood. It didn't dance like a flame, it shone like a beacon. Then I noticed that a hissing sound was coming from the direction of the fire pit. The light kept getting stronger and stronger, and the hissing sound got louder and louder.

Within a minute, the pile of wood was literally screaming at us, while shining with an eerie red light that lit the entire clearing and our assembled faces with the color of fresh blood. Oddly enough, there was little smoke and no visible flames. We weren't getting what we wanted, but we sure were getting something .

Another minute passed and the top of the wood pile suddenly burst into flames. They didn't start in one place and then spread to cover the surface; the entire surface lit up at once. Slowly, the screaming died and the red glare faded away, replaced by the dancing yellow flames of burning wood.

To this day, some of the group nod and smile as they remember. With the eerie light and unearthly sounds, they dubbed it The Night The Aliens Landed. Although it certainly wasn't what we wanted or expected, everybody loved it.

What Went Wrong?

All three ignition systems performed exactly as hoped. Having seen the previous failure in the ignition system, I had over designed the new system to such a point that it worked well. Three times in a row, no less, the igniters burned. The igniters simply failed to light the fire.

The fault was in the liquid fuel that had been poured over the wood before the event was begun. Since it was commercial charcoal lighter fluid, it had been designed to soak into charcoal, get it lit rapidly, and burn off without flavoring the food. When applied to the firewood, it would have been adequate to get the wood started, except that it had evaporated away during the unusually long delay during the beginning of the festivities.

So each igniter, in turn, spilled its firey guts out vainly trying to light wood that wasn't as inflammable as I had planned.

The third "brute force" igniter saved the day. It was composed of four highway safety flares, arranged in a sort of pyramid such that it would jet large quantities of fire in all directions. While the other igniters gave their all and failed to light the wood, the brute force one washed the inside of the wood pile with flame until it finally caught fire.

I had forgotten, though, that automotive flares made a hissing sound as they burned. As more and more of the flares in the brute force igniter started up, they contributed to the red light and sound until the result was a radiant, screaming pile of wood.

The Subsequent Experiment

Given the "evaporated fuel" hypothesis, I spent some time in small scale experiments with various mixtures in order to retard evaporation as well as accelerate the burning of the bonfire. I also reduced the ignition system to two electrically triggered igniters.

The new system was used for real at the next outdoor event. It worked very well, but I had overestimated the liquid fuel when scaling up from the small experiments to the bonfire. That bonfire was nicknamed The Great Chicago Fire. Later I perfected the fuel mixture and dosage.

Conclusion

The system seems pretty solid now, and reliably produces just the right amount of fire, on cue. I continue to tinker with some of parts, especially the electrical igniters. But there aren't any surprises anymore.

That's a pity. I rather miss The Night The Aliens Landed. Perhaps, unintentionally you understand, they will come back again some time.

Thank you for visiting. Your comments are welcome.
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