Pyro : Magnesium Fires

Here is a small picture of me burning some magnesium at the BurningMan festival in 1996 (click it to see a larger version).

About

The image above is NOT a long exposure image- this is what burning magnesium looks like to the naked eye. That's me striking a large chunk of the stuff to make it emit a shower of unbelievably white sparks.

If you have any questions about burning magnesium, please see the FAQ below...

Magnesium Fire FAQ (frequently Asked Questions)

Feb, 1998

Contents:

• Introduction
• Disclaimer
• Basic Concepts
  • Where do I get magnesium (and how can I be sure it's magnesium)?
  • How much should I get?
  • How do you get the fire started?
  • So you have a very bright fire. What else can I do with it?
  • How long does it last?
• Safety
  • Yourself
  • Others
• About this document

Introduction:

Allo! Welcome to the wonderful world of true and total super-pyromania! Magnesium fires are a bright, beautiful, and wonderfully dangerous thing.

Magnesium is a not particularly easy to light metal that once it does catch on fire it burns very brightly, bright enough to cause eye damage if stared into. Magnesium burns at 5400 degrees Fahrenheit and reacts explosively with certain salt nitrates. Also, it produces slightly to very toxic fumes when it burns, depending on the type of magnesium alloy and surface conditions (grease, etc.) of the piece being burnt. Safety is of the utmost concern. Please be sure to read the safety section.

Disclaimer:

I cannot guarantee that you will not be blown to bits, burnt to a crisp, blinded permanently, blinded temporarily, thrown in jail, raped by a large inmate, forced to eat gruel, permanently psychologically damaged, or any number of other nasty things that happen to people who willingly partake in such actions as those described herein. I disown any statements herein. I'm do not speaking for anyone, not even myself.

Basic Concepts:

• "Where do I get Magnesium?" You can get magnesium from several sources: bike frames, aircraft wheels, chaninsaw engine cases, Porche engine cases, various transmission cases, and my personal favorite Volkswagen engine cases and fan manifolds. In my personal opinion though bike frames and jet wheels cost too much, or are too hard to come by. There are several parts off of old Volkswagens and Porsches that are made of a mainly magnesium alloy. It's pretty easy to convince junk yards to give you their broken or cracked engines instead of the scrappers by offering them a little more than the scrappers would. I give them ~$6.00 per engine case-both sides, or ~$2.00 for a fan manifold. Haggle. See how low they'll go. And MOST important, when you go to get them BRING VINEGAR and A FILE. "Why?!??", you ask... Slap me if you already know this... :) Because that's how you tell if they are magnesium or just aluminum. You use the file to scratch the metal to remove the Oxide layer and expose some fresh shiny metal. You then pour some vinegar (most household vinegars work fine- I use apple) onto the exposed portion. If the metal fizzes and bubbles then it's magnesium ( or mainly magnesium anyway).
• "How much should I get" At Burning Man 1996 I did a teaser fire which people really enjoyed which only used a single fan manifold and one case half. This year I did a huge fire- which involved the digging, of 7 foot deep pit- with about 20 full size engine cases. Much more than a single case becomes a real bitch if you have to put it out immediately though.
• "How do you get the fire started?", you might ask. Well, a large hot bonfire will do it. There is no need to mix up some thermite or anything exotic (as I have done). Although a good blowtorch can help (which is what I used at Burning Man). The best way I've found is to set up a wooden teepee with the engine case on top such that the flames blow through the case itself. After several minutes of exposure to hot flanes the fire will begin to acquire an orange look, this is a sign that the case is almost ready. There will be an oxide layer all over the surface of the magnesium preventing the metal from really going up. If you begin to hit the case with something (I use a steel rod) this will knock off the oxide layer and the metal will ignite.
• "So you have a very bright fire. What else can I do with it?", you might ask if you are a super-pyromaniac. Well, for fun just add water. "Water!?!?!!! Come on- you're kidding right?", you say. Well actually, yes. Water will make the magnesium fire flare up and can even cause an explosion. The fire is hot enough to free the Oxygen from the Hydrogen and then re-burn the Oxygen. This makes it burn much more brightly but also shortens the lifetime of the fire. You could take a burning pile and put some red flares on top of it and have the worlds brightest hottest sunday (yum! ;-) ). Also if you put the magnesium in a narrow pit you could have a disco ball above it and then you would have the worlds brightest disco ball (I haven't done this - yet...).
• "How long does it last?"- I've found that a single Volkswagen engine block will last about an hour. Although more engines cause a critical mass effect to take place instead of simple multiplication. My huge fire at Burning Man used about 20 cases and only lasted about 8 hours.

Safety:

For yourself (since you can't protect others if you are a blind, charred piece of meat):

1. Don't stare into a magnesium fire, the fire is many times brighter than the sun at a normal distance. Please take this seriously I got flash blindness the first big fire I had and was nearly blind for two days. Flash blindness is unpleasant it feels like you have sand under your eyelids. A quick one or two second glance every several minutes seems to be okay. This can be extended slightly if you have welding goggles, or an arc welding mask. If you do get flash blindness please see a doctor immediately, they can give you the same drugs as those for designed for welders who get flash blindness-this will minimize the amount of damage and shorten the discomfort.
2. If you are the person stoking the fire, don't glance at the fire too much. This is how I got blinded even though I knew better.
3. Don't ever have a magnesium fire indoors or breath the smoke, fumes or ash from the fire (since you can't be sure of the exact contents of the alloy without thorough chemical analysis). Magnesium Oxide itself is quite caustic and can screw up your lungs. I personally have never had any problems from the smoke or fumes, but I'm sure that a filter mask cannot hurt.
4. Don't try to put out a magnesium fire with water. This will only cause it to burn more intensely (albeit less efficiently) and can even cause it to explode. If you must put the fire out, you'll have to bury it completely (be aware that pieces can burn underground for a long time).
5. Be very careful if beating on, kicking up, or splashing water on magnesium. Even a small piece of magnesium can burn through clothes and burn flesh. I had a burning white piece fall between my ankle an sock one time and still have the scar to prove it...

For Others:

1. Make sure that other people don't stare at the fire. Explain that they should only glance at it for a few seconds. Be watchful, make sure that no one is staring at it. This may sound easy, but you would be amazed at how stupid people can be. I once had a person who absolutely wouldn't believe that the light was dangerous because, "it is so beatiful." - this person was on acid and I basically had to stand between them and the magnesium fire. I suggest having a bullhorn present - people listen better when they can't even hear themselves think.
2. If you are going to burn more than a pound or two of magnesium, you should burn it in a pit, This will prevent the casual passerby, or distant observer from blinding themselves since they will probably be out of earshot for your warnings. Magnesium fires really are bright enough to blind people a good distance away.
3. Make sure that no one tries to put out the fire with water, since this could cause an explosion if they throw enough water on at once. If they don't believe you demonstrate with a little water on a glowing white piece of metal.
4. Make sure people are a safe distance away if you are hitting, kicking up, or throwing water on the magnesium. Make sure that someone else is watching the crowd while you are doing such things.

About this document:

This document was written entirely be me, Meico.

I have had over a dozen magnesium bonfires ranging in size from tiny to disgustingly huge. I was the man in the metal hat that hosted magnesium fires at Illumination Camp (The Illumination Project) during Burning Man 1996 and 1997. If you have any questions or information to add please contact me.

Have a supercalafragalistic day!