Introduction: Moose/Bear Repellent Aka FLAME THROWER

Picture of Moose/Bear Repellent Aka FLAME THROWER

The idea for this project was born from trying to get our campfires started with kindling and wood so wet we couldn't get them to burn with dry paper. Sure charcoal lighter would work but where's the fun in that?

Please don't be misled by the term Moose/Bear Repellent, I only used it to create more interest. It probably wouldn't deter a bear that was intent on inflicting harm. If anyone wishes to visit Alaska to enjoy the great outdoors, I would recommend some sort of bear deterrent. Be advised a big ol' can of pepper spray isn't always effective, they have even been seen licking it from the ground. Making plenty of noise or an occasional blast on a portable air horn while you're hiking will keep surprise encounters to a minimum. As for the moose, beware, they usually aren't afraid of anything and would love a chance to bully you for your snacks, or for no reason at all.    

Some words of caution: Be safe, have a fire extinguisher or bucket of water nearby and someone else there in case whats burning is you. Never operate indoors. You wouldn't pee up a rope or spit into the wind, it'll get ya if you do, so don't use it when the wind is blowing.

Materials: All materials are available at Lowes or Home Depot except the butane refills and birch plywood, which can be found at tobacco shops and craft stores respectively. Total estimated cost $50-$60 US.
8 in. of 1-1/2 in. type "L" copper tubing
1-1/2 in. copper end cap
1-1/4 in. copper end cap
1 in. length of 3/4 in. soft copper tubing
1/4 in. x 1-3/4 in. hitch pin
4 in. x 4 in. x 5MM extruded acrylic
24 in. x 12 in. x 1/8 in. birch plywood
1-1/4 in. length of 1/4 in. oak dowel
1-1/2 in. x 1-1/8 in. x 1/2 in. long aluminum angle
4 pcs. 1/8 in. tension pins 5/8 in. long
12 pcs. #8 x 3/4 flat head wood screws
3 pcs. #6-32 x 1/4 in. flat head machine screws
1 pc. #8-32 x 1 in. flat head machine screw
2 pcs. #6 x 1/2 in. flat head wood screws
1 pc. #8-32 x 1/4 in. flat head machine screw and lock nut
1 pc. #10-24 x 3/8 in. pan head machine screw, flat washer, lock washer and nut
pulse ignition for gas grill with wiring harness ( Lowes or Home Depot )
1 pc. AA battery
2.1 oz. can butane
1 paper clip
1 pc. 3/4 in nylon pipe cap
Titebond wood glue
super glue
a bit of solder

Tools used:

Laser cutter
Pipe cutter
Hand drill and assorted bits
Dremel with cut-off wheel and drum sander
Wire crimper
Sand paper
Propane torch
Router table
Phillips screwdriver

Below are the drawing files for the grip frame.

Step 1: Choose the Fuel Supply and Material for the Fuel Chamber

Picture of Choose the Fuel Supply and Material for the Fuel Chamber

PIC#1 I chose to use a 2.1 oz. can of Bernzomatic butane because I already had it on hand.

PIC#2 I checked a copper tubing handbook and found the size of copper tube that's inside diameter most closely matched the outside diameter of the butane supply I was using, which happens to be 1-1/2 inch type "L" tubing. I cut an eight inch length of the 1-1/2" type "L" copper tubing. I Purchased a 1-1/2 inch end cap to fit over one end of the tube and another 1-1/4 inch cap to fit inside the tube.

PIC#3 The end of the nozzle on the butane supply is stepped.

PIC#4 A hole for the butane nozzle must be placed in exact center of the 1-1/4 inch end cap. To find center I painted the inside of the cap with a black marker and allowed the ink to dry.

PIC#5 Coiled up scotchbrite pad rotated gently inside the 1-1/4 inch cap to remove the ink.

PIC#6 If done as described you should have a mark dead center. Drill that mark with a 1/16 inch bit followed by a bit just large enough for the butane nozzle to pass through until it contacts the first step on the butane nozzle.

Step 2: Fabricating the Fuel Chamber Parts

Picture of Fabricating the Fuel Chamber Parts

PIC#1 The plans I drew up required an opening cut in the fuel chamber to allow for the parts and linkage that force the butane cylinder forward to discharge it's contents. I wanted to keep the tolerance tight so I cut the opening .96in wide x 1.3in long, .25in from the tube end. I cut the 1-1/2" end cap to match.

PIC#2 Scribed a line from the center of the cutout to the opposite end of the tube and marked a center location 1-1/4 inch from the tube end. Transferred the center mark 120 degrees in both directions and drilled all three locations with a 1/16 inch bit, followed by a 1/8 inch bit and finally a counter sink.

PIC#3 The 1-1/4 inch end cap was too long to fit the butane cylinder correctly so I shortened it to 3/4 inch long. I inserted it open end first into the end of the tube with the three holes until it was 5/8 inch inch from the end. Then marked the location of the three holes in the tube onto the 1-1/4 inch end cap. Drilled those three locations with a 3/32 inch drill and followed with a #6-32 tap.

PIC#4 Drilled two 1/16 inch holes 180 degrees apart, 90 degrees from the center of the slot and 3/4 inch from the closed end of the 1-1/2 inch end cap.

PIC#5 Drilled a hole in the end of the cap with a #29 drill bit and chased it with a #8-32 tap. the location isn't critical just needs to be centered in the slot.

PIC#6 Ran a #8-32 x 1 inch screw into the hole previously threaded and marked all the threads protruding with black paint.

PIC#7 Removed the screw and chucked it in a drill motor, ran the drill full speed while holding a small file against the threads I marked with black paint until they were removed.

PIC#8 Taped the 1-1/2 inch end cap to the fuel chamber tube to transfer the two holes in the end cap to the tube. Then ran through with a 1/16" drill followed by a 1/4" drill.

PIC#9 I cut a piece of 3/4 inch copper tube 5/8 inch long and fish mouthed one end with a drum sander to fit the contour of the fuel chamber tube. This will be the fuel chamber mounting boss.

PIC#10 The four main parts of the fuel chamber.

PIC#11 Soldered the mounting boss to the fuel chamber, assembled the fuel chamber and end cap with a 1/4 inch x 1-3/4 inch hitch pin.

PIC#12 Time to slide the 1-1/4 inch end cap in place and secure with three #6-32 x 1/4 inch screws.

PIC#13 I drilled a 7/32 inch hole 1/4 inch from the end of the tube and attached the ceramic insulated ignitor electrode with a #10-24 x 3/8 inch machine screw, flat washer lock washer and nut. I then drilled a 3/16 inch hole 180 degrees from the first hole 1/4 inch from the end of the tube and fastened a ground electrode fashioned from a paper clip with a #8-32 x 1/4 inch long machine screw and lock nut through this hole.

PIC#14 For asthetic purposes I capped the end of the fuel chamber mounting boss with a nylon cap.

Step 3: Building the Grip Frame

Picture of Building the Grip Frame

PIC#1 I built the grip frame using 1/8 inch birch plywood, it is made up of eleven layers laminated together. I used a laser to cut all the parts but they can also be cut with a scroll saw and drilled with a hand drill if necessary.

PIC#2 Glued it all up with Titebond wood glue. Held the pieces in alignment with 1/8 inch cotter pins and spring clamps until the glue set.

PIC#3 The right side frame is glued up from three layers, the left side eight layers. This facilitates easy disassembly and reassembly. The 1/4 inch oak dowel was cut slightly long to be trimmed after final assembly. Also the dowel is only glued to the left side. Both sides were held together while the glue set to hold the dowel in alignment.

PIC#4 This picture shows the placement of the cotter pins used to hold the left and right sides together as I rounded the right side edges( bottom) on the router table. Used a 1/4 inch round over bit.

PIC#5 This shows the completed grip frame assembled for the first time. I used #8 x 3/4 inch screws.

PIC#6 I drilled a 1/8 inch diameter hole in the center of the grip frame and glued a 1/8 inch diameter x 3/4 inch tension pin to engage the mounting boss soldered to the fuel chamber.

PIC#7 I cut a 1/2 inch long piece of 1-1/2 inch x 1-1/8 inch x 1/8 inch aluminum angle to secure the rear of the fuel chamber to the grip frame. Drilled two 1/8 inch holes through the 1-1/8 inch leg 1/2 inch apart and attached to the grip frame with two #6 x 1/2 inch wood screws. Then measured to locate the hole for the pin which protrudes through the rear of the fuel chamber and grip frame and drilled a 3/32 inch hole at that location.

Step 4: Action Parts Assembly and Adjustment

Picture of Action Parts Assembly and Adjustment

PIC#1 These are the parts needed to depress the ignitor and slide the fuel cylinder forward to discharge it's contents. They were laser cut using 5mm extruded acrylic. It is possible to cut them with a scroll saw and drill the holes with a hand drill. The ignitor push rod was made longer than needed so the ignitor and fuel discharge could be timed. Two of the parts, noted in the picture have been omitted in the final assembly because they were not needed and added to overall complexity.

PIC#2 Before assembling I removed all sharp edges with 220 grit sandpaper.

PIC#3 I used 1/8 inch diameter tension pins 5/8 inch long to allow all the parts to pivot. I inserted the shanks of drill bits to hold the parts aligned as the glue set (super glue), applied the glue only to the ends of the pins so the parts pivot as intended.

PIC#4 This is the left side grip frame with the action parts and ignitor in place. I inserted a fuel cylinder in the fuel chamber, assembled the fuel chamber, left side grip frame and right side cover to test the timing, trimming the ignitor push rod untill satisfactory timing was established.

PIC#5 The completed action assembly. As you can see quite a bit of the ignitor push rod had to be removed to time the ignitor and fuel cylinder.

Step 5: Making a Spark

Picture of Making a Spark

PIC#1 To ignite the fuel, I borrowed the pulse ignition from my gas grill. It uses a single AA battery and supplies a steady flow of sparks at about six to eight per second and will jump about 3/4 inch. The grip frame was designed around the ignitor to keep the the total package as compact as possible.

PIC#2 This is the cap that contains the battery and push button contact in the ignitor body. To keep the grip frame as slim as possible I removed the flange around the base of the cap with a Dremel and drum sander.

PIC#3 To secure the ignitor to the grip frame I simply screwed the cap to the ignitor body sandwiching the bottom of the grip frame. It only needs to be finger tight to hold it securely.

PIC#4 I attached the ignitor electrode to the fuel chamber with a #10-24 machine screw, flat washer and lock washer. The ground wire will be attached to the fuel chamber under this nut.

PIC#5 Final step before test firing, I shortened the wire harness that was part or the pulse ignition and attached one wire to the ceramic insulated electrode and grounded the other to the fuel chamber. Time to gather a video camera and a fire extinguisher and go outside.


sypher made it! (author)2017-10-17

I kinda made the thing, the said Instructable was directly responsible for my inspiration.

sypher (author)2017-10-17

similar idea, I used a quad striker instead. also reconfigured the layout. it works pretty much the same, nice reasonable sized fireball...

sypher (author)sypher2017-10-17

it's also unfinished... I might just use this version and the data collected to make a better (safer) version.

daniel.stillmunks (author)2017-03-06

hello? I just posted a ""nice"" comment. WHERE THE HELL IS IT?

03//06//17 12:04 pm = noonish.

capt. dan stillmuks

JeremR3 (author)2016-08-07

The title is qite misleading....why didn't you post this under another category ? That would have been more honest.

DeeC4 (author)2015-08-22

Thank you for showing us all the steps to make this cool thing. Now the truth is that most of us actually can't really take advantage of these plans other than trying to find someone capable of actually making it. Please SOMEONE step up to the plate and start making these so we can pay you for making us one. The question I have is the back up cartridges of fuel.--contact me at "" and allow me to pay someone for a finished, working example--thanks.

DawsonD (author)2015-03-01

would you build and sell one because I don't have the tools, skill, and time to make one. Also how do you reload the flamethrower

DeeC4 (author)DawsonD2015-08-22

Let me know if anyone has contacted you with an offer to make one for you. What would you be willing to pay for one? Actually if I could get detailed plans I could possibly look into getting these produced-it all depends upon what price point we all will be willing to pay and also to have access to fuel cell back up loads. This could be a perfect hand held unit to be at the ready beside your car door or your door at home--or bedside table.

Explorerkawana (author)2015-07-22

so wish I had time to make this thing would you be interested in selling one?

DeeC4 (author)Explorerkawana2015-08-22

If anyone contacts you about making and selling this product -please contact me as I want to buy one myself. What would you be willing to pay for one? Also I don't see the fuel supply so I would want to be able to have a somewhat larger supply or at least back up cannisters or whatever is used for fuel so that I could rapidly re-load. Thanks--

DCComicsFan08 (author)2015-05-17

It looks like a Heat Gun from the new CW Flash series. I LOVE it!

CordellM (author)2015-03-18

dude i would so want to this myself for reason one i can learn alot and i can improve on this pus my guy u are a genius and a level100 prodigy good luck in your future indevors

American Ruin (author)2014-09-25

This is something out of my childhood dreams. Nice work.

jcastrillon restrepo (author)2013-12-10

Hi, nice instructable!.

I have one of these ( instead of the igniter you used.
do you think it'll work?, I'm worried about the input voltage.

ps: i have the cable with the electrode and the push button switch on their own ..............
thanks in advance

flytye (author)2013-10-29

how can I get the PDF file.

Edgar (author)2013-03-18

If this is not Fun Time Stuff, I don't know what is! :D
Went to my Blog:

dman789 (author)2012-10-18

have you thought about selling these?

madmanu1999 (author)2012-09-30

CONGRATULATIONS!!! you did a really well project.At this moment I haven´t got a laser cutter (isn´t a bit weird a 13 years old boy with a laser cutter?) so I cannot do it but it´s a really amazing instructable.Allso, here in spain it´s a bit difficult to find butane, but with deodorant and matches you can do a really cool flamethrower

magranger15 (author)madmanu19992012-10-05

Is butane not allowed in Spain?

madmanu1999 (author)magranger152012-10-12

No, it's just difficult to find.In Spain the lighters and all the stuff that uses butane is so cheap that you just buy a new one.

xSmok3y (author)2012-05-30

Just finished mine

mamajr96 (author)2012-05-01

About how much did everything cost?

xSmok3y (author)2012-03-12

what is the scale for the pdf file? I need it for my lazer cutter. Thanks!

Blaise_Gauba (author)2012-03-02

Very nice work. Very Steam Punk looking. The copper tubing probably gives it some weight whereas I might consider using PVC. Do you think that that would be a melting hazard? Anyway, I read all the way through your Instructable and found it very thorough except I ended up becoming a bit lost with the soldered fuel chamber with the nylon end-cap. If I may be so bold as to ask, what is that chamber for again? And, do you have any photos of that chamber taken from a 3/4 view so we can get a visual perspective of it? As it stands though, I love it and it seems like a fun enough project to take on. Be safe and responsible folks. :-)

antoon (author)2012-02-27

really cool but i have no way of making it :(
creddits to the maker

Football viking boy (author)2012-02-03

Great job! I've been looking around for instructions to a flamethrower. This is really great but I might need to simplify it.

moneyfuskie935 (author)2012-01-26

All I can say is... WOWZA!!!!

broken-feather (author)2011-12-18

Very well thought out and I do believe it could be a formidable deterrent for lots of situations. Gob well done. I like it.

Severan_Mal (author)2011-12-14

Lol love the title and vid!

archieburden (author)2011-12-01

its all good until it blows up in your face...

PDRWLSN (author)archieburden2011-12-05

Blowing up is highly unlikely. The fuel can't even burn until it is discharged into the atmosphere. Also the valve on the butane cartridge is shielded from heat so the possibility of melting the valve and discharging all the fuel contents at once is eliminated.

hossweightlifter (author)2011-11-28

This is amazing.........

PDRWLSN (author)hossweightlifter2011-12-01

Thank you, appreciate the comment.

FriendOfHumanity (author)2011-11-19

Wow! That's a great instructable.
You have created a thing of beauty.

? sad


PDRWLSN (author)FriendOfHumanity2011-11-19

Thank you, glad you like it. Copper is going to be used in more of my projects.

Sergei- (author)2011-11-15


Thats awsome

I have some similar plans that i baught at an online book shop that use to be in australia about 15 years ago

Turns out these plans are from the information unlimited people and this book shop was selling a cd's worth full of things like this

That looks great can't wait to look more closely at it


PDRWLSN (author)Sergei-2011-11-15

Thank you.
Can you supply the website? I'd like to check it out.

Sergei- (author)PDRWLSN2011-11-22


The place i got the cd from has closed down but i can give you the site that origonaly had the plans for sale but they sell them at different prices and it's full of things like kits for things not just the plans/schematics

They have all sorts of cool stuff there


PDRWLSN (author)Sergei-2011-11-26

Thanks for the info, it's a cool site. Going to spend more time checking out their stuff later.

ilpug (author)2011-11-22

This is amazing, if a bit complicated for me.

If you put this in your pocket, it might be considered a concealed weapon, as this is probably extremely illegal.

Does this have a safety?

PDRWLSN (author)ilpug2011-11-22

Anything one could fit in a pocket that could cause harm to another could be considered a concealed weapon, it would depend on the intent of the one in possesion and what the one in possesion were doing at the time.

As for legality, it's legal where I live but there may be locations it may not be.

No there is no mechanical interlock, I wouldn't transport this, or my camp stove for that matter, with a butane cylinder installed.

ilpug (author)PDRWLSN2011-11-22

Yeah, true. Anyway, great design and build!

PDRWLSN (author)ilpug2011-11-22

Thank you. Happy you like it.

theguyhere (author)2011-11-20

That amazing... Now get a bigger spray can and make a bullpup rifle :P

deobomb (author)2011-11-15

would wood work for the triger and push rods?

PDRWLSN (author)deobomb2011-11-15

I don't see why it wouldn't. I'd use birch plywood laminated to the proper thickness for strength though.

batonas (author)2011-11-15

nice design man

PDRWLSN (author)batonas2011-11-15

Thank you.

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