Smoke bomb ingredient: potassium nitrate (aka saltpeter)

 3612 3387771401 B4A64Bb459 B

I learned how to make smoke bombs when I was 12 by reading a recipe in Abbie Hoffman's Steal This Book. The recipe calls for two ingredients: ordinary sugar and potassium nitrate (also known as saltpeter). In those days I was able to buy potassium nitrate from the pharmacy at K-Mart in Boulder, Colorado.

Here's Hoffman's recipe:


Sometimes it becomes strategically correct to confuse the opposition and provide a smoke screen to aid an escape. A real home-made stroke bomb can be made by combining four parts sugar to six parts saltpeter (available at all chemical supply stores). This mixture must then be heated over a very low flame. It will blend into a plastic substance. When this starts to gel, remove from the heat and allow the plastic to cool. Embed a few wooden match heads into the mass while it's still pliable and attach a fuse.

The smoke bomb itself is a non-explosive and non-flame-producing, so no extreme safety requirements are needed. About a pound of the plastic will produce thick enough smoke to fill a city block. Just make sure you know which way the wind is blowing. Weathermen-women!

The problem with this recipe is that the mixture can easily ignite while heating it over a stove burner. My friend and I made a batch when I was 13, and it went off in his kitchen and caused a lot of damage (when it burns it produces a red hot liquid that looks like molten lava). So I do not recommend this recipe. Has anyone tried melting the sugar first, then turning off the burner and pouring the potassium nitrate into the molten sugar? I've also read that you can mix together powdered sugar and potassium nitrate and ignite the powder. Other people have reported success adding melted paraffin to the powdered mixture.

Potassium nitrate is also an ingredient in gunpowder (which also contains charcoal and sulfur). There's an interesting paragraph about potassium nitrate in William Gurstelle's excellent book about acceptable risk-taking, Absinthe & Flamethrowers: Projects and Ruminations on the Art of Living:

In parts of China, gunpowder makers could merely scoop up saltpeter that lay on the ground, the result of fermentation of soil and animal waste in the humid subtropical climate. Europeans living in a dryer, colder environment had to work much harder to get saltpeter. The early European method of obtaining potassium nitrate involved aggregating great heaps of rotting organic matter, especially that which contained high percentages of rotted meat and animal dung. "Petermen" would search out promising places to collect their smelly treasure. Abandoned outhouses and animal pens were especially prized. The petermen picked up and taste-tested handfuls of dirt. When they found a place that tasted right, they'd cart out the soil, boil it in vats, then evaporate the liquid and strain the slurry-like residue. The result was high-purity saltpeter.
The image of a peterman tasting saltpeter brings to mind the widely held belief that militaries add saltpeter to soldier's food as a way to deaden their sex drives. But saltpeter's reputation as an anti-Viagra is false. From Snopes:
There's no proof potassium nitrate (also known as saltpeter) has any effect on libido, plus or minus, so there would be nothing to be gained from such a doctoring of edibles. Yes, saltpeter has long rumored to be an anaphrodisiac, a substance that reduces sexual drive. But it's all rumor and no fact.
If you are interested in experimenting with potassium nitrate, you can buy it from Amazon. 5 lb Potassium Nitrate on Amazon

Photo by M. Kelley. Creative Commons Attribution 2.0 Generic license.



  1. Some friends of mine used to just mix saltpeter and sugar together and it worked fine. The only problem was that it was very difficult to light. So difficult, in fact, that some of them took to using a jar of it as an ashtray in a show of cool bravado when their parents weren’t around. Well, you can guess what happened. The neighbors saw smoke billowing out of the windows and called the fire department. Naturally, you can imagine the parents’ reaction when they got home. Fortunately, nothing else burned, although the thing left a big scar on the bedroom ceiling, so they just went ahead and refurbished the entire room.

    1. I used Icing Sugar and don’t recall having problems lighting it, but that was 20 years ago.

  2. I’ve always wondered if the trick from Stalag 17 and the ping pong balls worked in real life.

    1. my russian buddy assures me that the ping pong balls cut up and wrapped tightly in foil does work.

  3. I tried to make gunpower as a lad substituting sugar for pure carbon and then using potasium nitrate (bought at the local drug store) and sulfur (hobby shop). I just mixed it manually. It smoked like mad but didn’t explode (which is is good in retrospect since I had no business trying to make that much gunpowder as a lad).

    So mixing it without heating should result in a reasonable smoke bomb.

  4. I made some homemade bottle rockets when I was 12 from powdered sugar, saltpeter and a little sulfur from some plans I bought from an ad in the back of Popular Mechanics. Worked great. There were also plans to make E and F sized model rocket engines to be used with a 3 stage rocket that could break the sound barrier. Still would like to do that.

    1. ganesha71 – YES! I think that’s the same book my brother and I used. I’ve been sitting here trying to remember what it was called and I think it was from Teleflight and it was called something like Amateur Rocket Motor Construction.

      I think it suggested using a rock tumbler to mix the powders. We didn’t have one and just rolled a paint can around on the driveway for a bit. I’m thinking that was where we went wrong.

      1. There’s a 2004 edition on sale at Amazon. The author listed is David Sleeter and the publisher is Teleflite

        1. Yep- that’s the book. The original version that he was selling out of the back of Popular Mechanics was a very good book. Well illustrated and well written.

  5. My brother and I tried to make our own rocket motors when we were kids. Researched the composition of gunpowder using the encyclopedias at school. Went to the fertilizer store and bought a few pounds of potassium nitrate and sulfur. Carbon we figured was just ground up charcoal briquettes.

    Mixed it all together and made… something that smoked like crazy. We added some sugar because we read that burning sugar can act as an oxidizer in a how-to-make-your-own-fireworks book that the school had (heh… wonder if that’s still in the stacks).

    Never got any thrust, but a few times we enveloped our entire block in a very smelly cloud. The coolest thing we made was a lightbulb filled with the stink-producing mixture (I think we saw this on tv). We tested it in a lamp in our garage once. That was enough.

    We also burned some pretty big holes through our asphalt driveway. Something I suspect the people in that picture will end up doing.

  6. Yeah I did this too as a early teen. Same results, lots of smoke. I don’t think I bothered to melt it together. We eviscerated firecrackers to get our gunpowder for unsafe experiments in stump destruction.

    My biggest problem with one of my favorite Star Trek TOS episodes, Arena, is when Spock can recognize Potassium Nitrate, a generic white powder, from the viewscreen. “He knows, Doctor. He has reasoned it out.”

    And of course, Mythbusters tested out the cannon:

  7. Easiest smoke bomb ever:

    Wrap a plastic ping pong ball up in tin foil, leaving only a tiny hole in the top. Make sure you add a bit of a tin foil handle on as well so you can actually hold it. Now heat the tin foil up from beneath with a lighter (making sure the hole is at the top). Wait several seconds… Throw away from people when smoke starts spewing out the hole.

    Try not to inhale.

  8. And check out the book “Rocket Boys” by Homer Hickam. “Don’t blow yourself up”, his mother used to tell him….

  9. I used to do this all the time as a kid. The little convenience store across the street sold saltpeter (in fact, we ended up buying so much one summer they ended up doubling the price–free market in action, I guess!).

    For what it’s worth, it works just fine by just mixing the sugar and the saltpeter together; no melting is required.

  10. Potassium nitrate is available in quantities useful for experimentation at most stores with a gardening department. You just have to know what to look for.

  11. It bothers me the recipe just doesn’t say 2 parts sugar to 3 parts saltpeter.

    How can I trust the recipe if I can trust the writer to reduce fractions?

  12. A friend of mine had an old 1950’s ‘Boys Annual’ which had a recipe for gunpowder in it. We fired off loads of it.

    You’d be dragged through the tabloids if you printed that in a kids’ book now.

  13. It is not strictly necessary to heat the mixture. Melting it in that fashion is merely a means of making it burn more slowly and produce slightly thicker smoke.

    I achieve quite similar effects by making a paste of the ingredients with denatured alcohol and then allowing them to dry into a solid inside of a container (a trick that also works with solid rocket fuels).

    The fuel source for smoke mixtures is very versatile. Similar results can be achieved simply by saturating newspaper with dissolved saltpeter and rolling it into a tightly wound cylinder. This also has the benefit of producing something that can be held like a flare (with fireproof gloves on), or even thrown (in nonflammable environments).

    Experiment a little bit and you’ll find it’s really very easy to find something much safer than melting that recipe on a stovetop, and you’ll have a lot of fun discovering methods for yourself! :)

  14. you can also make a rocket propellant/gunpowder substitute with 1 part sugar, i part saltpeter, 1/10th part iron oxide.

    put ingredients in a pot with lots of water, bring to a boil reduce heat and stir until it reaches the consistency of oatmeal. Remove from heat, let cool and sift through a piece of screen to get uniform particle size. (window screens work great).

    Sugar provides the fuel, saltpeter the oxidant and the iron maintains consistent burning temperature.

    Note: while this works (well) it’ll gum up equipment with a foul caramel like substance.

    Also known as R-candy.

  15. When I was a teen I came across the same formula. I picked up the ingredients at a local health food store, and mixed them together. I gave the leftovers to a friend and told them, “This probably won’t do anything, since the ratios are completely off, but don’t set it off in town.”

    An hour later, I get pulled over while riding on my bicycle. Apparently, the friend told his grandmother, who called the cops, and my name matched a gang ‘leader’ from 10 years ago.

    They confiscated my small packet of ‘gunpowder’ before I could test it. Ah, the life of the small (pop. 3k), rural town.

  16. We used to make these flying contraption. Take a cap from a vodka bottle. Pull out the round lining inside the cap, save it. Fill the cap with salpeter/sugar mixture then cover it with the round lining. Bend the sides of the cap so it holds the lining in place. Poke a small hole off the center on the cap. Find a parking lot. Light the a match near the hole, set it on ground. Watch it hover, fly and leave burn marks on the ground.

  17. At the age of 11 (in 1961), a friend and I blew a shallow crater in her parent’s basement.

    And this in an age before thousands of recipes on the web. We had to do actual research.

    For all you guys out there: just thought you should know that girls can be just as dangerously stupid as boys!

    It was so cool … !

  18. As a kid I got the recipe from Abbie’s book as well.
    My pals and I just skipped the entire cooking step and mixed it 1/2 and 1/2 +/- (sugar to saltpeter) in penny-candy, paper bags (recall those?). Twist the top into a long fuse and you are ready for urban mayhem.
    Setting them off in a wooded area (OF COURSE BE CAREFUL!) is great fun since the trees contain the smoke quite well. Great movie prop.
    FYI: I just bought a big bottle of saltpeter off the shelf at Rite Aid.

  19. The recipe makes no sense at all. Use a double boiler, the same as you would do if you were making candles.

    Also, do it outside in case of an accidental ignition.

  20. Hydroponic shops are a good source of un-adulterated fertilizers. Plus they don’t think twice when you bring up a rental truck and ask them to load a pallet or two of chemicals. I used powered sugar and got the ignition going with a small bit of kerosene or methyl alcohol, both available at the hardware store.

  21. Ew.

    “Potassium nitrate is an efficient oxidizer, which produces a lilac flame upon burning due to the presence of potassium. It is therefore used in amateur rocket propellants and in several fireworks such as smoke bombs. It is also added to pre-rolled cigarettes to maintain an even burn of the tobacco.

  22. We just mixed the powders together dry, wrapped them in tinfoil, and used fuses to light them. Worked fine.

    JG, where do they sell it at Rite-Aid? Is it fertilizer, or first aid, or what?

    1. Just like we did when I was a kid. Just mix up the dry ingredients tight and put it in some staircase or car and light up and run.
      But I don’t know if Abbie Hoffman knew allot about these things and large crowd tactics (I know he was in the battle for Chicago but did he use these?).

      I mean, you can just light up a car tire and get more or less the same effect. Which, essentially, is just allot of smoke up your face when the wind changes direction or when the other side throw it back to you and then fires a cannister of pepperspray into the crowd for good measure.

      There are some things you can mix in to change the colour of the smoke… also I vaguely remember we used some kind of baking soda … this was awhile ago.

  23. hmph, i had no idea the ingredients for black powder could be so easily obtained. sulfur is pretty cheap. awesome.

  24. Be careful… if you do things like this at the wrong time, or in the wrong place, or if you’re just unlucky, you can end up in jail, like Byron Sonne.

    For more info on him, see:

  25. Maybe that myth originated with the petermen. I don’t imagine a man whose occupation involved taste testing dirt laden with rotting organic matter would have much luck with women…

  26. For once, a cool project that I’ve actually done myself! I always feel like such a loser with all the cool stuff others are doing…

    Anyhow, the description quoted above is misleading. I’m pretty sure there were flames. At any rate, the stuff I made melted aluminum foil that I put it on to burn.

    Also, the smoke was very acrid and would probably kill anyone with asthma (which I’ve since developed).

    So yes, I’d like to see a better recipe too.

  27. Oh please. I learned how to make gunpowder from watching the musical “1776.” So if Homeland Security ever ask me how I learned such a subversive act maybe I can sing out the recipe.

    Abigail Adams: Because you neglected to tell us how saltpeter is made.

    John Adams: Now, have you done as I asked?

    Abigail: No, John, I have not.

    John: Well, why have you not?

    Abigail: Because you neglected to tell us how saltpeter is made.

    John: By treating sodium nitrate with potassium chloride, of course.

    Abigail: Oh, yes, of course.

    John: Will it be done, then?

  28. Yep did this as teenagers.

    The powder mix worked just as well for us. A film canister of the powder ignited using a sparkler was enough.

    We tried to make the melted version, but predictably it ignited. Luckily we were working outside on the barbecue.

  29. I would NOT recommend melting potassium nitrate with anything, unless you know what you’re doing. The trick I believe is to grind your ingredients very very fine and then mix them thoroughly.

    In high school we stumbled upon a pretty cool smoke bomb mixture: I think it was 2 parts ammonium nitrate and 1 part fine zinc powder. Mix thoroughly in a VERY dry place. Squirt a dropperful of water on top and stand back. We would sprinkle some iodine on top to make the smoke purple. Very cool.

    If you have the money, you can buy a diy smoke bomb kit: (they sell fuse and bulk saltpeter too!)

  30. A good source for chemicals, and folks I like to support, is

    In my college days we had a small cannon. We’d buy black powder at a gun shop, tie some in a handkerchief with a length of line cord with one fine strand of wire for an igniter. Some newspaper packing and it would make a nice noise.

    A chemistry major taught us how to fulminate mercury…bigger bang, crazy times. One day someone realized that the cannon bore was just right for a tennis ball. It put a wicked backspin on the ball, we watched it curve up over the women’s dorm. Days later someone found a charred tennis ball several blocks away.

    Still later someone realized that pool balls were also an appropriate size. Fortunately we never trie that.

  31. I Did It by this same recipe three times, the first time it worked perfectly, the las two it blew up while i was cooking the mixture to the melting point trashing the kitchen and nearly my hands and face. My experience is that melting the recipe in a can/pan over direct flame, even if it is a very small one has a really good chance of setting it of unless you know exaclty what you are doing. Wich I do Not.

    Maybe the double boiler or any recipe that avoids heat until the time of ignition would work better an avoid a lot of risks.

  32. 1 Tbsp Potassium Permangenate
    1 Cup Glycerin

    Put KMNO4 into a heat resistant cup, add glycerin on top. Smoke! Enjoy!

  33. Sugar and potassium nitrate have a high activation energy (meaning it’s hard to light). Grinding them together or melting them together helps, but it can still be difficult to ignite and I’ve noticed no difference in adding paraffin wax.

    If you want to make a smoke bomb this way, I’ve found that the easiest way is just to make a cup out of aluminum foil, stir some sugar and potassium nitrate together in the cup and ignite with a propane torch.

    For easier igniting, I would read over the “Gummy Bear Sacrifice” demonstration ( ). Potassium chlorate and sugar have a much lower activation energy (so don’t try heating this mixture). It’s also cleaner combustion (not as much smoke), so some additional impurities might be necessary to get that true ninja effect.

  34. In the early 1960s after using up the little bottles of potassium nitrate from our Gilbert chemistry sets, my neighborhood gang would hit up the country store where it was available from the McCormick spice rack. The same store also sold bulk sulfur and, of course, sugar. We did a dry mix with charcoal, and it was great for getting rid of unwanted ship models.
    Later we acquired waterproof rocket fuse from a hobby shop’s rocket section, punched out used aerosol cans and filled them with the stuff. They actually exploded with dangerous shrapnel — hence the need for a real (and long) fuse.
    We also built rockets using spent CO2 cartridges filled with regular match heads for motors. All the parents in the neighborhood, who were all smokers, would complain about there never being any matches in the house.

  35. well I made these recently for a theater production so I made many of them to get the recipe right.
    the flare up happned only once with 50/50 mix on an electric coil heater.
    when you add the saltpeter to the molten sugar it get´s grainy and difficult to mix a homogeneous paste but with a little elbow grease you can mix it pretty well. It solidifies to a hard candy block which if left out to the atmosphere is hygroscopic to the point of self disolution. Lighting it is not too difficult and some burning paper will suffice, for example setting it on a bed of crumbled newspaper.
    whith this 50/50 mixture it burns too fast aproximately 30 seconds per 80 grams.
    To slow it down to human speed you can use some sodium bicarbonate aproximately a teaspoon per half a cup of each other reactant.
    Changing the ratios will make it>
    slower as you add more sugar or longer hydrocarbons like paraffin, beeswax, oil, etc. for the fuel.
    longer as you add more oxidant with potassium nitrate, faster more powerful oxidisers like clorine nitrate, the shorter smaller or more oxigen rich the fuel, like using lactose or fructose.
    and other substances will modify the reaction time and the quantity of the smoke, like baking soda, powdered aluminium. baking soda will actually make it rise and fluffy.

    hope this helps.
    take it easy and if you will heat it up while actually mixing the oxidiser be very careful as flare ups will occur at lower temperatures then you would expect.
    this is a lesser version of thermite use it responsibly as incendiarys may become dangerous and may be illegal

  36. Wow, this takes me back!

    We used to raid the schools chemical or agriculture stores for KNO3 all the time! You don’t have to cook it together on the stove to get it to work-even just a good mix will ignite if you use a magnesium-strip fuse.

    Back in highschool we made a 1kg bundle that smoked out the main quadrangle, but even making one in an old local film canister is enough for alot of smoke!

    Another easy thing to do if you are interested is to make thermite. You can eiter get it to produce pure molten iron, or you can isolate some titanium dioxide from paint or sunscreen to produce some pure titanium!

  37. A sparkler makes a good fuse for this mixture, or other hard-to-ignite things. Burns plenty hot.

  38. My brother and I made all sorts of fireworks when we were kids (in the seventies) – even persuaded our parents to buy the ingredients (we were very much “free-range kids”). I remember the pink flame the sugar and saltpeter mix made – and all the smoke!

  39. Careful with that stuff. We used it back when we were students, when we played air soft games in abandoned buildings. The smoke clouds were so huge that it looked like the building was on fire. Cops came and were not amused when they found a group of youngsters wielding realistic plastic copies of submachine guns.

  40. We did this in my high school chemistry class. The plan was to melt the sugar and saltpeter together, add a little strip of magnesium for a wick, and then take it outside and light it off. We only got to step 1, because it ended up igniting while we were melting it and a whole hallway of the school had to be evacuated until the air cleared. I’d probably end up on the no-fly list if the same event happened today.

Comments are closed.