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700 Match Heads

Yesterday during spring/summer cleaning I found 35 match books. Having nothing better to do, I burned them.

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How to Make Thermite

January 18, 2010 2 comments

Thermite is an incendiary reaction that can burn as hot as 2500°C or more. That means that if you lit a pound of thermite on top of your car it would melt through your hood, through your engine, through your driveway, and make a hole in the ground. Thermite is a reaction between a metal (aluminum, magnesium) and a metal oxide (iron oxide, copper oxide, manganese oxide…) this reaction has a high ignition temperature, but once its ignited it supplies it’s own oxygen. This allows for some interesting applications, for example thermite is still used today for underwater welding.

Safety Precautions

Before you get started, you must realize that what you are about to do is a dangerous and energetic reaction that should only be performed with the utmost care. Besides its ridiculously high temperature, thermite also emits UV radiation that can do permanent damage to your eyes and if you don’t want to wear a welding mask, at least put on a pair of good quality sun glasses. Also, metals with a low melting point (zinc, lead) will vaporize and explode if near the thermite reaction.

Supplies

There are many kinds of thermite, but the most common uses iron oxide and aluminum powder, both of which can be made at home (see my instructions for How to Make Iron Oxide and How to Make Aluminum Powder). You also need a way to ignite the thermite. Most people use magnesium ribbon, but I haven’t had much luck with that and usually use potassium permanganate and glycerine. Potassium permanganate is a filter cleaner and a dye sold at hardware stores or online at e-Bay. Glycerine is a skin care produce and can be found at any drug store like CVS and once again at e-Bay. When mixed they spurt flames like my mother’s cooking. Additional things that you might want include a flowerpot to contain the mixture while it’s burning, bricks to hold it up, and something to melt. If you don’t have anything to destroy, at the very least just put some sand under it to keep it from ruining your driveway. What ever you do, don’t use water to catch the drops. Water will instantly vaporize, explode, and spray you with molten iron- generally something to avoid. If you’re interested, this is an example of what happens when you have even the slightest amount of moisture.

1. By weight the ratio of iron oxide to aluminum powder is 8-3. Both should be powdered as fine as possible as this will make it burn hotter and ignite easier. Measure them out, and mix as thoroughly as possible- this will make it burn faster and hotter and is well worth your time.

2. Pour the thermite into your container. Flower pots are most commonly used, but almost anything will work. Flower pots are used because clay is one of the only materials that will still be there after hell has reigned. If you do use a flower pot, you should consider using two. The second pot will contain the shards of the first and reduce the risk of it breaking halfway through. The only thing that I would advise against is glass as it might shatter before it melts.

3. If you’re using magnesium, stick it in, fray the top to make it easier to light, and light it. If you’re using potassium permanganate, then pour it in, mix it in a little bit with the thermite, and add the glycerine. Rule of thumb is two to three parts glycerine to one part potassium permanganate. It usually helps to stir the ingredients after you add the glycerine. If it still won’t light, adding powdered magnesium or powder rubbed off of a sparkler makes it easier to ignite. Whatever you do, stand way back.

4. If it lights, then yell, cheer, and behold the awesome power of thermite. If it doesn’t light, then re-evaluate and try something different.

Thermite can also be bought online from e-Bay or Skylighter. If you buy from e-Bay then you can sometimes buy it as a kit, but you will have to buy the chemicals individually from Skylighter.

If you have any success with this and feel like more of a challenge, or just want to try something different, then this website has good instructions for silicon dioxide thermite and other more exotic recipes.

How to Make Aluminum Powder

January 10, 2010 3 comments

Aluminum  Powder is an ingredient in thermite and when ground fine enough becomes a flash powder that could demolish a building in seconds. Photographers use it to create a bright light for a picture, wood workers use it to fill joints, and aluminum powder was even what the tin man used as makeup.

Supplies

The supplies for this one are easy, just aluminum and something to grind it in. The most common source of aluminum is foil, but this isn’t always the cheapest. Other sources include drink cans, aluminum pots and pans or even heat syncs off of computers; it doesn’t really matter what alloy of aluminum. If you’re out of ideas, try taking a trip to the dump. The blender is usually more expensive and difficult to find. Whether you use a two-hundred dollar blender or a ten-dollar coffee grinder, it doesn’t really matter. Keep in mind that you get what you paid for and you will have to be a lot nicer to a cheaper blender and it will probably break sooner. There are alternatives to a blender like using a bench grinder or a fine grit power sander. Here are plans for one such alternative. The result from this may be finer or coarser and you should decide for yourself what works best.

1. No matter what size blender you got, the blades are usually small and you will have to make your aluminum fit. For foil, this means tearing it into ribbons, but for something thicker you will probably have to get out some tin snips. If the blades jam up, it puts stress on the joint and the motor-both of which will eventually break. Don’t take the chance and use small pieces of aluminum. Only use something thicker than an aluminum can if you’re very confident- foil isn’t expensive, but blenders are and replacing them gets old fast.

2. The longer you blend it, the finer the powder will be. You will need to continually add more, especially at the beginning, because the volume decreases and the powder won’t reach the bottom of the blades. A blender won’t ever give you particles smaller than that of fine sand. If you intend to use it for anything other than rough thermite then you will have to ball mill it.

3. Aluminum oxidizes on contact with oxygen and blending it uncovers new surfaces. When you open the lid, oxygen pours in, and if the powder oxidizes fast enough, then it will get hot enough to ignite. To avoid this, open the lid at least every ten to fifteen minutes. Make sure you mill your aluminum in a well-ventilates area and let the powder settle before you open the lid; aluminum is poisonous and breathing it in is not a good idea.

4. Store in a cool dry place; I personally suggest glass jars of some kind.

If you are lazy, and or have the money for it, you can also buy aluminum powder at Skylighter, or on e-Bay. e-Bay will be cheaper, but you won’t always find powder of the same size or purity, also make sure that you’re buying from a trusted vendor.

Also, here is an interesting video demonstration of thermite, and if you’re interested in trying a different type of thermite, try here.