Campfire Reflector Wall Doesn’t Work… Part 2

Last week I wrote an article on the science of why a campfire reflector wall, as shown in the original article, doesn’t work to reflect heat the way we have been led to believe for so many years.

I explained how the Inverse Square Law affects the heat radiation, so there would be no noticeable difference in temperature rise.

I must admit, a lot of the responses I read across various discussion boards and forums was absolutely fun to read. I mean I was getting railed left and right. Lets see some of the more fun ones

  • Have they ever camped?
  • If it’s good enough for the SAS, it’s good enough for me
  • Personally I don’t think it matters what you call it as several people have stated and those with any amount of experience out in the wild know, building a so called reflector wall behind your fire WORKS as far as increasing the amount of heat reaching your shelter! TBH the how and why doesn’t matter as FACTS prove it works, backwoods men, trails men and native peoples would not have been using it for centuries if it didn’t…. You know what they say, those that can do, those that can’t teach and those that can do neither write about it! Oh and by the way according to the researchers bees can’t fly either…
  • Obviously written by someone who has not spent much time outside in the cold roasting on one side and freezing on the other. Remember these are the same folks that could “prove” that bumble bees could not fly.
  • This article is bs. His reasoning is pseudoscience. A block of wood may not reflect as well as a mirror but the same principle applies. If the heat reflector didn’t work, then ovens wouldn’t work and solar thermal power plants wouldn’t work and solar ignition with a concave mirror wouldn’t work. Hell even dish antennas wouldn’t work.
  • I call BS on this. It’s using a bunch of Sci-babble to sound authoritative, and it completely dismisses that fact that one is always warmer with a reflector wall, as opposed to not having one.In real science, you are supposed to be able to observe an effect (and we all have), and then seek to come up with the most viable theory to explain the observation…not ignore the observable effect, and come up with a theory to explain why we are ignoring it…Also, the flashlite example they are using, can only be produced by the fact that the flashlite itself has a reflector in it to focus it’s light in a concentrated direction…which proves reflectors work…in the very example they are trying to do just the opposite.

The last one about the flashlight really had me chuckling, because, well, if the person actually knew what I did for a living one would see the irony in it. Suffice it to say I manipulate light.

The list goes on, but you get the point.

I was very specific in saying a reflector wall fire in front of the fire. I even showed an illustration, which by the way is from the SAS survival manual. We were measuring reflectiveness, not it’s ability to block wind and draft smoke, which many people seemed to try and use to poke holes at the article. The irony, however, is that in the last paragraph of the article I even suggested people use it to draft smoke and not use it to depend on it for reflecting heat back to you.

So lets address this I haven’t camped before and have no real life experience. Those that know me were probably having a heart attack from laughing so hard. That said, I would like to share with you a few other people who feel the same way I do about the reflector wall.

Are you familiar with André-François Bourbeau? If not I suggest you look up his bona-fides

Bourbeau writes— On one occasion, I wanted to verify the value of the popular survival technique that suggests installing a wall of logs or rocks behind the fire to reflect the heat toward yourself. Searching the literature, I found the origin of this technique in Camping and Woodcraft, a book by author G.W. Sears, alias Nessmuk, written in 1880. On the first day of a camping trip, having forgotten his axe, he boasted of his idea to compensate by using his small hatchet to cut a poplar into four foot lengths and piling them into a sloping wall behind the fire to reflect heat to his bed. At the same time it was customary to sleep on a bed of fir branches, wrapped in woolen blankets, feet near a fire burning all through the night.

Since Nessmuk slept very well that night (without an axe), he boldly stated that he had discovered the best way to keep warm. What he didn’t mention was that it was perhaps a quiet and warm night. However, he did admit that long poles of firewood were abundant. Also, since it was the first night of his trip, his clothing and blankets were dry, which added to his comfort. In other words, if he slept well that night, it might not at all be because of the reflector wall. Yet, many early nineteenth century authors cited Nessmuk, and eventually the technique appeared as fact in later publications, even in the army survival manuals!

So one Autumn night I amused myself by sleeping by the fire in my own back yard, thermometer in hand, measuring the temperature where I lay. Then I leaned a full sheet of plywood upright against two lawn chairs as a reflector wall behind the fire. The result? To my surprise, I obtained no difference, not even a single degree!

I repeated the experiment three times, always with the same outcome.

I am sure many of you are still rolling your eyes and that is still not enough, so how about this.

In his book, Camping in the Old Style, David Wescott writes

Wescott— The inverse square law states that the effect of a glowing object is one divided by the distance squared. Better stated, if the fire warms the front of a shelter from one yard away, when the camper lays down to sleep and is two yards away, he will receive only one-fourth of the available heat (at three yards, one-ninth, and so on). This is do to the fact that the light’heat spreads out and is less intense as it travels from its source

knowledge of this law tells us that the efficiency of the popular reflector fire talked about and illustrated in many traditional texts is a MYTH [emphasis mine]. Most illustrations show the wall and fire so far from the camper or shelter that they provide a marginal return on the energy lost in their construction. To work at all, the wall must be as close to the fire and as close to the camper as possible. In this position the wall creates better fire action by actuating a draft as well as spreading out and directing the glow or radiating heat from the fire.

Campfire Reflector Wall Doesn’t Work… Part 2

Mors Kochanski calls this setup a back-wall fire, noting that it it’s a misnomer to call it a reflector fire at all. In order for an object to be a reflector it must have a mirror like surface. Light waves that strike it bounce off at the same frequency. A back-wall fire, on the other hand, absorbs these waves and reemits them at a lower frequency waves are overcome by the inverse square law and are in most cases, rendered relatively useless.

So all that to say, I suppose if I am going to be accused of having no experience and never having slept out a day in my life, I couldn’t ask for better company than these three gentlemen.

For now, excuse me as the four us go sit in a nice warm and cozy lodge, while we go plot other ways to deceive you

And remember “Science is the father of knowledge, but opinion breeds ignorance”—Hippocrates

Alan Halcon