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Home-made Flash Bangs Answered

hey everybody, i'm looking to find out how to make the most efficent, cost effect and relatively DIY flash bangs for your day-to-day blinding needs. i know there are some fairly routine methods follow out there, but i am hoping that if enough of us instructabilians share our knowledge and experiences it will be possible to create a dam good design. thanks for your help


It depends on the quality of your materials, but what your going to want to do is take magnesium powder, thermite, potassium perchlorate, sulfer, and using a static reducing spray on the surface you want to mix them VERY CAREFULLY. if you don't have the means to make thermite (like me) use some diesel fuel (about 4% of the mixture) and aluminum powder, thermite will ensure that the magnesium lights. you want a ratio of about 7 potassium perchlorate to every 4 magnesium, thermite and sulfur mixture. you should wrap this in any kind of tube formation, and use a long fuse (if you have any mortors lying around these are my favorite) and if you think kind of like the more compact the explosion, the better the flash and the bang, you will be better off. you don't have to worry to much about suffocating the mixture because potassium perchlorate is an oxidizer and you should be alright. if you can't find a static reducing spray you can also use a solution of 9 parts water to every 1 part fabric softener. other good explosions that may be easier to make are ammonium nitrate bombs (96% ammonium nitrate rich fertilizer, 4% diesel gasoline, and magnesium- powdered or ribbons) and PTER

Actually.... it's the other way around.
The magnesium ignites the thermite.

I mean.... I'm assuming you're refering to the high temperature redox reaction between iron oxide and aluminum.

Thermite needs extreme temperatures before it can occur because the iron oxide has to loosen it's grip on the oxygen, and that doesn't start happening until some fairly high temperatures.

After the iron oxide releases the oxygen it bonds to the aluminum, leaving the iron, which tends to convert into a plasma state since it absorbs most of the free energy released by the reaction, free to recombine with atmospheric oxygen.

Iron Plasma tends to burn bright.

If you have a vacuum or an oxygen free environment to cool the Iron in , this is a great way to make pure iron.

Magnesium burns readily in an oxygen rich environment, and that can occur by heating the magnesium with a cheap lighter for a few seconds. The sustained temperature increase is such that it can initiate a thermite reaction.

I didn't know that, I always thought that magnesium would have to reach a very high temperature before igniting because of only seen anyone do it with a blow torch. You don't necessarily need the thermite in the reaction, just the aluminum powder, potasium perchlorate and sulfer. I haven't actually fooled around with any of it yet, I get most of my recipes from finding information on web forums and then going to the TM 30-210 army improvised munitions handbook to see if it would be possible for that reaction to take place, this is one that I have always been a little fuzzy on, and I don't know how the reaction takes place because as I've said before, I have never worked with magnesium aluminum or iron powders. If you were to run a current through the thermite before (super thermite I believe?) would that make it easier for it to ignite? because I was relying on the themite to ignite the entire thing.

Ehh... any reduction in the auto ignition temperature is probably going to scale with the electricity you put into the process. In most cases... you'd probably be better off making an electrical arc to ignite the thermite. Electrical Arcs are basically a form of plasma. They're thousands of degrees in some cases, and can jump start a number of high activation energy reactions, assuming they're self sustaining after the initial electrical input.

Be careful with the potassium perchlorate.
it's notoriously unstable. Light, heat, age.... lots of things can spontaneously ignite it. i'd suggest using a more stable oxidizing agent like nitrate or sulfate.

Since we're talking about electrical explosives.... A very rudimentary capacitor can be made by mixing aluminum powder into Vaseline. the amount of electrical charge that can be stored on the aluminum/vaseline capacitor is dependent on the concentration of aluminum powder; since you want the capacitor to overload, you kinda have to find your balance. too much aluminum powder and it wil take a huge charge to detonate. Not enough aluminum powder and it won't properly conduct electricity.

Anyway... just some ideas.

Good ideas, but because it's a flash bang, wouldn't any electrical ignition be hard to put into something that needs to be small and light enough to be thrown by hand a distance of at least 10 yards? It seems like the best way to go might be to just put a non-electrical blasting cap into it, ignite the fuse and hope that it doesn't fail?

A capacitor is going to take a small amount of time to overload.
Depending on the voltage and amperage of the power source and the capacitance of the capacitor, it could easily take several seconds to overload the vaseline/aluminum powder mix.

As an aside, you could use any powdered metal, including Magnesium, but depending on the reactivity, that could be really dangerous. Magnesium powder isvhighly explosive.

I just recently realized you could just take a 7:4 ratio of potassium perchlorate and 400 mesh aluminum powder and mix them. Not nearly as hard as I was making it out to be. if you take a wooden stick and rap a bunch of 1-3 inch strips of paper around it in the same spot until you get a thick layer, about 1/2 to 1 inch in diameter and tape it off you can make a container and then just cap one side, fill it, cap the other side and put in a fuse. Very bright flash, very bright sound, and you don't need more than a few grams. probably the cheapest way, especially since you can get aluminum powder pretty much anywhere. I don't know the exact procces to making potasium perchlorate but as far as I can tell it goes hand in hand with pottasium chlorate which you can make with bleach and some potassium chlorate which is a substitute for table salt. People made it way harder than it needed to be

Look at this instructable. It isn't a flash bang but it is blinding;


If your in to more serious stuff you can take phospherous and black powder in an air tight tight completely filled but keep phospherous on the top and do not expose to air it will ignite thats why its the igniter then on the top of the outside of the tank add magnesium fuses for that extra shine

Get an inside aluminum can, mix Thermite, Aluminum, and Ammonium Perchlorate, then put an extended fuse in there, seal most of the can, put it inside an outer steel can that has an inside diameter of 3 inches, and is grade 80, then drill holes in the outer steel casing. Would this work as a decent flash bang? Would the pressure and heat be too much and damage the structural integrity of the outer steel casing? Could the PSI be deadly?


6 years ago

Tell me if this sounds plausible. (This is all hypothetical).

Get an inside aluminum can, mix Thermite, Aluminum, and Ammonium Perchlorate, then put an extended fuse in there, seal most of the can, put it inside an outer steel can that has an inside diameter of 3 inches, and is grade 80, then drill holes in the outer steel casing. Would this work as a decent flash bang? Would the pressure and heat be too much and damage the structural integrity of the outer steel casing? Could the PSI be deadly?

I have found that TNT's "Lightning Flash" Firework makes a great super bright flair when you Crush them up.

What i do is grab a pair of pliers pull out the fuse and save it cause i like to use them for other things. then i crush the fireworks and save the powder from them.
once you have a good amount of powder you grind it up so its really fine.
then you take a plastic straw like from a fast food place or what not, pinch the end with the pliers and melt the end with a lighter or something so that the end is closed off. get a small funle or use the paper and pour the powder into the open side of the straw (fill it to about 5 CM from the top). then get your pliers again and pinch off the top and close it off with your lighter just like you did with the bottom.

now when your ready to use it shake it a little to get the powder inside evenly moved around. then just light the either end untill it starts then just toss it on the ground.
I have found these to be VERY effective and bright! they dont make much noise but the still work great! there easy to make and are small and easy to carry around. they burn for a good long time.
Hope this helps I will be making an Instructable for this soon.


6 years ago

get a box of about 200 fire crackers and put the powder in a small plastic soda bottle, tape it shut with a fuse or flammable string sticking out and light it. glass bottles work to if you dont care about hurting anyone.

get the powder off a few sparkelers and crush it up as fine as possible it doesnt work to well packed together so spread it around a little and light


9 years ago

the thing about a "day-to-day flash bang" is the bang part. at the very least it could cause hearing damage. i would focus on the flash part. find things that burn bright: sparklers, road flares, and as some other people mentioned, magnesium. the key is getting it to burn fast, but not necessarily exlpode.

magnisium ribbon burns so bright that in school demistrations everyone has to put blue filters over their eyes

High powered flash powder: Potassium perchlorate and aluminum powder mixed in a 2:1 ratio. The perchlorate you can buy on unitednuclear.com and the aluminum you can buy on ebay. Buy an aluminum that is 400+ mesh and for best results use dark pyro aluminum. Confine a few grams in a two clear bottle caps with a fuse sticking out of the top one. Seal with hot glue. These things are very loud and produce a very bright flash. Use at night for best results. Oh, and the clear casing allows the bright explosion to be seen instead of looking through an opaque casing such as paper.

well why dont you use a magnesium powder for the flash and a sulphur compound for the bang? then you could use a sparkler to use as a fuse if you cant get a firework fuse, because fireworks are illegal here in Australia

can you gather enough flash powder to make a sufficient/effective bomb?

magnesium-magnesium fire starters aluminum powder -etch-a-sketch potassium nitrate-stump remover charcoal-making it, pencils, etc. sugar-grocery store some materials that can be found in easily found items flint and steel make hot sparks because the steel flakes off and burns.

Of course I, the 14 year old kid who can't buy these wonderful substances...has found the holy grail of illegal and dangerous and explosive (etc.) chemicals. unitednuclear.com you can get magnesium. I can't wait until i'm old enough to have my own place.

the only problem with unitednuclear.com is that it only delivers to america. to bad for us in oz.

Jest go with a bomch of flash things the ones in the camrus and put them in a box.

I have a friend that said all the chemicals you need are in an ectch a schetch. -Mike

This is true but having a reaction that burns at 6000F is a little deadly. For your day-to-day blinding needs.

As far as a flash-only grenade goes (no bang), you could try a high-amp, low volt capacitor shorted out by a carbon rod (pencil lead or the like). This is known to be VERY bright, and the brightest of setups can rival arc welding, with the difference being the carbon rod idea is visible light.

would a bunch of super bright LEDs hooked up to a capacitor work? although it wouldn't be as bright but you would possibly get more uses? its just a theory so don't hurt me

This may prove useful to you. scroll down on the page until you find the flash bangs, it tells what their made of.

one of the most effective ways to grind/shave meatals is your drill in a vice and put a piece of aluminum/magnesium(you'll find the bars are rectangular and too large so you'll have to cut it in half hot-dog style and dont worry itll fit(rectangles fit in octigons) rod in the chuck and get a piece of emrey cloth/sandpaper wrap it arund so it makes a u-tern put a plastic cup under AND VOILLA u just made 1 cup of powder just cus i can!!!

what you do is go to wall mart or bass pro or whatever and get 3 or 4 magnesium fire starters. you shave them into an empty check book box along whith some ground up fire works or gun powder. if you cand grind up the flint that comes stuck to the mag., do that too. cut a slot in the top of the box near 1 end and place lid on box. take some mag. ribbon and place in slot, then tip the box on end so all the grindings go to the ribbon. then light the ribbon

i think you can light magnesium with a magnesium ribbon. how would you grind up the flint....

i have found magnesium (ribbion included) to be fairly difficult to light, so i pack ground up sparkler dust, as it is easier to light.

interesting. maybe gunpowder covered in a thick layer of powdered flint? as said, flint sparks are brighter than the sun.

that is very possible, if you could case it and find the right kind of fuse...

The right kind of fuse would be easy. Use a fireworks fuse. They don't go out easy. The case would also be very simple. Use 2 sections of plastic pvc pipe, one fitting inside the other with about a 1/2 in. gap.

flint? please explain... (i got this image of me standing over something explosive trying to light it with a spark)

I'm not sure exactly how you'd do it, but the spark from flint is supposedly brighter than the sun.

interesting. maybe gunpowder covered in a thick layer of flint? as said, flint sparks are brighter than the sun.


10 years ago

thanks everyone for the help and tips, ill be coming back with an instructable soon. in the mean time please continue to throw in ideas, im sure they will come in handy.