Introduction: How to Make a Grease Bomb

What are just a few things that come to mind when you think multi day rafting trip? Desolate beaches perhaps? Caveman style technology? Motivated groups of danger seeking risk takers? Excessive amounts of bacon grease? If any of this sounds familiar, chances are you've gone rafting.

One of the biggest pyro displays one can pull off on a river trip is something called a grease bomb. Using a hot fire, a good amount of bacon grease, and some water, the little (or big) pyromaniac in us all can come out and play.

When executed correctly, the simple ingredients hurl a massive fireball skyward, produce squeals of enjoyment from the peanut gallery, and show your group a safe display of what happens when you show complete disregard for that age old saying of "don't pour water on a grease fire".

**Warning this Instructable involves fire, explosions, bacon grease, and danger. If you'd like to do another project involving copious amounts of bacon grease with a much lower danger factor, check out How to Make Bacon Soap. Grease bombs can be very dangerous and should only be done by experienced bacon grease pyrotechnicians. When done correctly they are a real good time.**


Step 1: Gather Grease

The first ingredient to a grease bomb is grease itself. You'll need a good amount of it - around 1 1/2 to 2 cups worth. The more grease you have, the bigger the bomb. Once you've done a small one, you might want to try making a grease bomb that uses more grease - around 3, 4 or more cups of grease ups the anti.

On the river we collect grease from bacon. Trip guests love bacon - so that means that we're usually cooking up POUNDS of the stuff on each trip. Each pound yields about 1/4 to 1/3 of a cup of grease, so collect all the grease you can until you've got about 2 cups worth.

Any fatty meat will produce good grease, so try rendering grease from different sources and see which produces the biggest fireball. (Anyone who can speak to the flammability of different types of animal fats please speak up).

After cooking the bacon, I let the grease cool. Then, I place a coffee filter on top of a non-breakable sealing container and pour the grease through. If your grease has little bits of meat in it, it won't work as well and it will splatter and sputter as you heat it. The coffee filter takes out all of those impurities and results in wonderful amber clear grease.

Step 2: Prep the Burn Area

The first thing on your mind when making a grease bomb should be safety. Because of their explosive nature grease bombs need to be preformed outdoors. Ideally the grease bomb should be set off on a non-flammable surface, such as a sandy beach or large rock. When igniting a grease bomb on a flammable surface such as a front lawn (pictured below) be sure to soak the entire lawn down with a hose before starting your fire.

Think hard about grease bomb placement. Grease bombs produce a giant fireball that rockets towards the sky. You'll need to pick a site that is not only clear of flammable objects around it, but also free of branches and trees above it.

If you have any doubts about your site, think things through, take the time to find the right place, and do things right. Ideally the grease bomb would be set off in the middle of an empty parking lot. Beaches afford the same level of safety and are good candidates. You should be thinking along these lines, not those of - yeah - the courtyard of my apartment building looks like a good place.

In most cases a grease bomb is a fun thing for you and other people to enjoy. That means onlookers - lots of them - so make sure that they are all at a safe distance from the fire (25 feet minimum). If they are too close they'll not only be in harms way, but they'll experience an unfortunate byproduct of a grease bomb - noncombusted grease that rains down from above.

Step 3: Boil Grease in a Can Over a Hot Fire

Before going any further you'll want to run through this quick safety checklist just to be sure that you've met the requirements from the previous step.

  • Is there a fire ban in my area/state?
  • Is there anything flammable around me?
  • Is my burn site non-flammable? And, if not have I hosed my burn site down with water?
  • Is there anything above my fire which could burn (trees awnings etc...)
  • Is the peanut gallery located a safe distance away from the fire so they don't get burned?

Once you've determined that the scene is safe, you are ready to proceed.

You'll want to use a blower, fan, boat pump, hair dryer or billows to make a really hot fire. Regular BBQ coals make great fuel, they just need a little oxygen to reach their full potential. For more extensive coal lighting instructions check out: Best Way to Start BBQ Coals.

Once the fire is burning really well put away the blower, pump or what have you. Next, pour the grease into a suitably sized can for the amount of grease thats been collected and place it right inside the pile of coals. Sometimes the fire is hot enough to heat the grease on the grill itself, but I've found that direct heat from the coals works best.

Heat the grease until it's boiling and watch it closely.

During this time, duct tape a second can onto the end of a long pole or stick. Old boat oars work particularly well - they are about 10 feet long and allow the master of ceremonies (grease igniter) to be at a safe distance from the action.

Finally, build a small barricade using whatever you have around. On the river we use our dry boxes - old WWII boxes that the military used to ship ammunition and generators to the front. You'll want to use this barricade to help hold the oar in place over the fire as well. It also creates a nice hiding spot for the grease igniter to hide behind when the big moment comes.

Step 4: 1, 2, 3 Ignition

Once the grease is boiling in the can it will then go through a few phases.

First it will just bubble a bit. Then, any impurities present in the grease will begin sputtering and spitting small bits of grease out of the can. Chances are, they will fall into the fire below and create small grease fires around the can.

This is a good thing.

Once the fire is burning around the grease can itself, and ideally, on top of the actual grease, it's ready for ignition. (See 5th photo below).

Using the oar cantilevered over the barricade, extend the can of water duck taped onto the end of it and move it into position directly over the can of flaming grease.

Do one more safety check before asking for a count down and then confidently pour the water out of the can on the oar and into the boiling can of grease below. The grease bomb will ignite as soon as the water touches the grease.

Experiment with emptying out different amounts of water onto the grease in order to get different size/multiple fireballs. The more grease you have, the more times you'll able to set the bomb off. Each fireball seems to consumer around 1-2 cups of grease depending on how much water is poured.

Step 5: Extinguish the Fire and Marvel

Once the inner pyro has been satiated, or when you've run out of grease in the can, extinguish the fire with a hose and wet the entire area down again.

This grease bomb was done during June of 2008 in Oregon - a time when thousands of forest fires across the west coast were burning out of control. As a result, we exercised every possible fire safety, stood by with hoses and fire extinguishers (as you may have learned by now, water on a grease fire doesn't work so well), soaked the lawn down before and after we ignited the grease bomb and kept close watch on our proceedings.

At the time, there was a fire ban in California, but not in Oregon, and so we deemed it safe to proceed. If there was a fire ban would not have done this. Forest fires are the real deal and cost not only loads of money, but endanger many lives. Take fire bans seriously and help prevent further fires!

Use good sense when making a grease bomb. Don't hurt yourself, or those around you. Hot fiery grease is fun to look at, but not fun to touch - it will burn you very badly. Do this at your own risk and be safe.

Comments

author
Logan+Hanssen made it!(author)2014-09-23

im going to try this with sap.

author
yusaku made it!(author)2012-01-10

For future refrence wax does that way better get one of those bucket type citronella candle from a hardware store put on fire till its completlymolten/on fire, then put some water in even a spoonful make a notible fireball and a cupful is insane. Use appropriate caustion of course.

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Derek+Vigil made it!(author)2011-06-16

On the picture of the flame it looks like theres a gorrilla on the top right hand corner.

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Screamo made it!(author)2010-09-25

THANK YOU FOR SHOWING ME THIS! I WILL NOW GO AND INDANGER THE LIVES OF MANY PEOPLE! HAHA ITS ON YOU! > : D

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schwabie made it!(author)2010-06-22

use bacon soda to help estinguish a grease fire.

author
Ranie-K made it!(author)2010-01-22

Here's a WWII poster slightly on topic:

Save Waste Fats For Explosives.jpg
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bombmaker2 made it!(author)2010-05-16

Okay, now that's awsome. USA! USA! USA!

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Ranie-K made it!(author)2010-05-17

Well, then I have to say Norway, Norway, Norway, I guess. It's also the Norwegian constitution day today, so...

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bombmaker2 made it!(author)2010-05-17

Sorry about that. I was thinking while typing and accidently typed that.

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malestripperbunnies made it!(author)2010-02-09

As much fun as this is, do not, I repeat, do NOT do this in your friends garage. Been there and done that. Nothing good will come from it. Well except the garage burning down in an insanely awesome inferno.

 I'd also like to say communism and all who practice it\support it sucks large, black-colored, lolli pops. Of the spoiled variety. Having said that I encourage you all to go forth and BURN THE WORLD DOWN.

author
Derin made it!(author)2009-12-12

Rule 1:
Don't take that to the airport.

author
notjustsomeone made it!(author)2008-08-05

I see that some people have talked about melting wax and it blowing up in their face, but no one seems to have made the connection yet. It's called a wax-water bomb. It's a very similar idea with much more spectacular results. You take a metal bucket and fill it with candles, or just a big 3-wick one, and then stick it in the middle of a campfire. Wait until it starts boiling, it may catch itself on fire, then to make the explosion you dumb a small quantity, like half a dixie cup, right on it, the more forceful the bigger the result. This makes for some cheap camping entertainment. Use extreme caution though, while it's probablly not going to splash on you it can produce a very large fireball. Of course this works best without any wind, and I've seen these make a 50+ foot collum of fire.

author
sharlston made it!(author)2009-06-16

that only works with parrafin wax

author
ScienceMMM made it!(author)2009-04-20

Cool! Can this be mixed with Ammonium Nitrate and encased in a shell?

author
PKTraceur made it!(author)2009-04-10

Nice noah! Im assuming Tim Anderson had something to do with this? Are there alterante ways of doing this, other than different fats? -PKT

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noahw made it!(author)2009-04-10

Nope - this is straight from my involvement in the white water rafting community. An amazing group of DIY problem solvers by their own right, that have absolutely no internet presence or documentation what so ever...well, besides this Instructable of course.

author
PKTraceur made it!(author)2009-04-10

What other kinds of DIY? -PKT

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thematthatter made it!(author)2008-08-10

the song that comes to mind is that song by the bloodhound gang, fire water burn

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computer41 made it!(author)2009-04-10

Yep :P haha good song!

author
rocksalt2342 made it!(author)2008-09-11

this proves Instructables aint for sissies.

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tippmannphreak made it!(author)2008-09-05

Back in the day my neighbor had a grease fire. He threw it in his back yard and, half asleep (he fell asleep with food on the stove), he threw it and got it all over him. I heard he has bad scars all over. Im never going to forget that smell. BE SAFE. this stuff can ruin your life if your not careful.

author
comander01 made it!(author)2008-08-23

If you go rafting, why don't you just throw the cup of grease in the river from the shore?

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iamthemargerineman made it!(author)2008-08-23

because rivers are home to many life forms. what if the green giant came up to with a pressurized tank of boiling lard and hosed the inside and outside of your house down? hmmmmmmm? ever think about it that way?

author
comander01 made it!(author)2008-08-25

The outide of my is not made of water, and therefore would not dissapate heat. Also, the oil only makes momentary contact with the water before exploding upwards. And if the green giant did hose down my house, then I'd have a mighty fine hunting trophy to show off to my friends.

author
Plasmana made it!(author)2008-08-11

This is really cool!

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DrCoolSanta made it!(author)2008-08-23

Sorry if I sound bad, but I genuinly am asking, is that the only thing you say? BUt anyway, it actually is very cool.

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Plasmana made it!(author)2008-08-23

That is not what I say all the time.

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DrCoolSanta made it!(author)2008-08-23

I have seen a tonne of your comments with you saying the same thing. Lol.

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Plasmana made it!(author)2008-08-24

Yeah, yeah, your right, I am doing this to make the authors a bit more happy about what they have done...

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DrCoolSanta made it!(author)2008-08-25

Lol yeah

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Plasmana made it!(author)2008-08-25

:)

author
Dan+Marshall made it!(author)2008-08-24

Good write up. Excellent safety suggestions.
Here's another take on grease bombs. It seems that there's a direct relationship between river guides and grease bombs.
mhtml:http://home.comcast.net/~makeyourowngokart/Grease_Bombs.mht

author
Weissensteinburg made it!(author)2008-08-04

Do you have to ignite the grease, or does the heat do that job for you?

author
PKM made it!(author)2008-08-04

The grease does have to be burning in the container for the best effect, but the fire often does that part for you. A few tips I found while doing this experiment (we used to call it the Hand Of God): - Candle wax works if you don't want to use fat, you can get a pack of eight candles more cheaply than four pounds of bacon - The thermal mass of the container you heat the fuel in is important- use a heavy-based unwanted saucepan, or put a handful of pennies in the bottom of your can, to give a higher mass of hot metal - Tall narrow containers like beer cans give a powerful vertical blast - Hot water gives a better blast because it takes less heat to boil it - If you drop the water from a greater height it seems to give a sharper blast

author
acer73 made it!(author)2008-08-04

I actually did this by accident with candle wax. I melted some wax in a pot and dipped a sponge in, at the time I was making a torch. So when I lit it on fire and relized it was too big of a fire for my bathroom, yes I know stupid mistake, I turned on the faucet and put it under the water and fire ball formed. It actually scarred me cause I didn't think it would happen with wax. Whats the science behind a grease bomb?

author
bikerbob2005 made it!(author)2008-08-08

Lets stick to the bacon grease a nice rolling boil can be in excess of 450 deg far. water for some reason doesent like to be hotter that 212 deg. water+hot grease yealds a bunch (tech term) of steam ( vaporized H2O ) with a flame source exposed to hydrogenated grease (cracking the O2) it makes for a rapid flame front hence the fireball not a technicality an explosion . My personal best for a flame front? 4 oz of axle grease on a dark runway slosh on it about a gallon of LOX people for miles will call in that fireball.

author
kill-a-watt made it!(author)2008-08-16

Ok, so the water goes in to the grease, which itself is well above the boiling point of water. The water tries to sink to the bottom, but it is also instantly converted to steam and expands to several times it's volume. That action flings grease droplets into the air which the fire then ignites.

I've seen something similar at a fast food place. A big scoop of ice is dropped into the fat fryer. The ice sinks to the bottom, melts, and then vaporizes. There's no fire, just a big billowing overflowing mess of hot oil. NOT SAFE TO DO INDOORS.

This smooth move was nicknamed "Gremlins" after the movie and that pool scene.

author
bikerbob2005 made it!(author)2008-08-16

about 30 years ago in a class i was taking we were told the math formula for how much energy it takes to turn water into steam as well as how many cubit feet if steam you got from a pound of water .realy big numbers,
supersteam is a totally different beast it scares me worst than my exwivessupersteam

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PKM made it!(author)2008-08-08

Where did you get a gallon of liquid oxygen? (If that's what you mean by LOX)

author
Weissensteinburg made it!(author)2008-08-08

Maybe he meant Smoked Salmon!

=p

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bikerbob2005 made it!(author)2008-08-08

does cream cheese keep it stable? Due to its cryogenic nature, LOX can cause the materials it touches to become extremely brittle. it is also a very powerful oxidizing agent: organic materials will burn rapidly and energetically in LOX. Further; if soaked in LOX some can detonate unpredictably on subsequent contact. Petrochemicals often exhibit this behavior, including asphalt.

author
bikerbob2005 made it!(author)2008-08-08

cute little truck brings it out to the fighter planes got a 2" hose and a pump got a gate valve on the truck and one on the plane so every time it fills up end up with a 2"hose 20 foot long full of LOX ( note all caps Lox is the stinky stuff ) BTW that is called rapid oxidation we called it fun

author
Goedjn made it!(author)2008-08-15

The water explodes into steam when it hits the hot oil. Steam is a lot bigger than water, so it splashes the oil around in a bunch of tiny droplets, which, being hot, exposed to fire, having a large surface area, and being well mixed with air, then proceed to burn. All the water's really doing is disbursing the oil in a cloud. --Goedjn

author
Weissensteinburg made it!(author)2008-08-04

Water goes to the bottom of the grease (as it always does), gets super heated to a boil, shoots to the top, and that sprays the fiery grease in the air.

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JamesRPatrick made it!(author)2008-08-05

You can get a pack of eight candles more cheaply than four pounds of bacon, but they don't taste very good.

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FunkNattidelic made it!(author)2008-08-05

My friend and i were by the river once, and we were melting candles (yeah we did it over a campifire, stupid us) and he threw in a honey lemon halls to make it like a citronella candle, to keep the bugs at bay. The wax started to turn to this goopey tar stuff and then ignited. I wasnt thinking that wax is like oil, and i got a big bucket of water and dumped it straight into the can. WORST MISTAKE IVE EVER MADE. I lost some eye brows, and got the crap scared outta me with a 6 foot mushroom cloud of fire engulfing my head. And of course we did it again when we got back to his house, just to show his dad, and he dropped the melted wax (twas in a popcan) before i put the water on and then it POOFED and set his lawn alight.

author
ducksan made it!(author)2008-08-13

This is an awesome instructable. Another, simpler (but less impressive), way to create and ignite a cloud of flammable vapor is to put kerosene in a spray bottle and spray it over a candle or flame. Don't point it at anyone. I wouldn't use gasoline, it's a bit more flammable, but more importantly might make some nasty smoke. Denatured alcohol is safer still, and if you dissolve boric acid in it you should get green fireballs =)

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grevious made it!(author)2008-08-13

or if you get a tube and put it in a loop, then tape some cloth to the end and soak the cloth in petrol, then pour a small amount of petrol into the tube and light the cloth, blow as hard as you can into the other end of the pipe, massive fire balls and flaming petrol goes all over the garage. first time we did this my mate held a lighter to it and w were in his garage, you do not wanna know what happened... hehe

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ducksan made it!(author)2008-08-14

....Wow. That's....really intense, and could be a sight to behold if you did it right and didn't burn down any garages, lol.

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grevious made it!(author)2008-08-14

hmm.. we didnt burn down the garage, but the whole back corner was on fire, aswell as him arm just past the elbow, he and the other guy starting putting it out, i got to the end of the garage (about 12 feet i travelled) and they had it all out, and no i wasnt running away, i went for the hose =D

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