MK: DIY Catapult A.K.A. the Coolest Way to Start a Fire




Introduction: MK: DIY Catapult A.K.A. the Coolest Way to Start a Fire

About: Whats up! My name is Michal and I love to work with all kinds of materials and to create awesome things. I usually work with metal, carbon and glass fiber, wood, plastic, etc. My favourite tools are probabl…

In this video I´m building a small catapult and shooting some fireballs!

With this great invention, starting the fire can be fun again! I built a copy of an ancient mechanism, the catapult, to throw fireballs with it. It was fun afternoon and luckily, it was raining, so i didn´t set my entire shop on fire.

Materials: 45mm(2 3/4") square pinewood, 19mm(3/4") pipe, bungee cord, c screws, zip ties, glue.

Tools: miter saw, japanese saw, drill, spade bits.

Step 1: Frame

I started by cutting the lumber to size with my miter saw. Then I made half laps using stopblocks. I made a lot of cuts across the board with blade lowered to half the width of the board itself, then I leveled the surface by moving the wood under the lowered blade. It´s hard to explain it in word, but once you see the video, it will be cystal clear :-) This worked really great and even though I have really cheap mitersaw, that isn´t even set properly, I created surprisingly accurate joints.

After my lumber was cut, I glued together the pieces I prepared. I was (probably unreasonably) worried that the lap joints glued together won´t be enough, so I glued a dowel in every corner for added strenght.

Step 2: Shoulder

I made the arm from harder wood, probably oak (I´m not sure since I used lumber from my scrap bin) because it´s the part with most stress, but again, it was very likely huge overkill. I widened the end by glueing on pieces of wood. Then I used largest spade bit I had and several wholesaws to create the void for the projectile. Lastly I added a layer of fireproof paint to protect it from the heat from the shots.

Later I started to make a pivot for the arm by drilling 3/4 inch hole into the frame with spade bit to accept the steel tube. Then I cut the tube to size, inserted it in the frame and secured it in place with countersunk screws.

Step 3: Firing Mechanism

I used a bungee cord as an accumulator of force to shoot the projectile. I ran it through the c-screws in the frame and in the arm and joined it with zip ties. In video I´m joining them with a piece of wire, but in the end I used the zip ties and they work great!

For a latch I used two c-screws, one in the frame and one in the arm. In the bottom position (when the bungee cord is stretched the most) I slide in a pin with a rope attached, to secure it in place.

Step 4: Projectiles

For projectiles I looked for small pebbles, no bigger than a coin. I wrapped them in cloth and tied a knot around it, leaving some of the cloth free. They resembled little onions a bit. Then I soaked them in gasoline. This worked great, because they caught on fire easily, but since only the gasoline not the actual cloth was on fire, they could be extinguished very easily.

Step 5: Shooting

I put a bunch of old newspapers in an old barrel and sprinkled them with gasoline. Then after few trials and errors, I discovered correct distance between the barrel and the catapult, chraged it with the projectile soaked in the gasoline, set the projectile on fire and fired it. It didn´t work instantly and I had to play with distances, angles and forces a bit but then, it was just beautiful to watch the burning shot fly in the air, then land in the barrel and the barrel catching on fire.


Thank you very much for reading, I had a lot of fun, hope you did too. Please subscribe to my YouTube channel for other fun projects and I´ll see you in few days with new build article!

Be the First to Share


    • Mason Jar Speed Challenge

      Mason Jar Speed Challenge
    • Bikes Challenge

      Bikes Challenge
    • Remix Contest

      Remix Contest

    2 Discussions

    Really cool! And great idea with the flaming projectiles!

    MK DIY
    MK DIY

    Reply 3 years ago

    Thank you! Yeah, it was real fun ☺️