root `index` legacy
DIY Grenade Taking you through the 3 prototypes I made for my DIY grenade, and sharing my thought process with you! `2020-06-27` The Idea About a year ago, I wanted to try to build a small grenade. I have no idea what made me want to build it, but it wasn't to harm anyone. I simply wanted to see if I would be able to make one to learn a bit more about how 3D printing and contact explosives worked. Unfortunately, I couldn't find any remanence of the first design I made. The only thing I remember is that I knew it wouldn't work before even printing it, so I decided to give up on the project. However, a few moths ago, I decided I would give another go at this project. Here is a list of the prototypes I made before arriving at the final version: The First Prototype Above is a photo of the first concrete prototype I made, about 4 months ago. How it worked is very simple. It consists of the following components: A hollow `20-face` shell (an icosahedron) which is made to rip apart into 20 sharp triangles when the explosive detonates. A `15mm` steel sphere with gun caps all around it that make a spark when they hit the outer shell. Some explosive gas (i.e. hydrogen) that fills the shell, which is menat to explode whenever the gun caps make a spark. Long story short, after one throws the grenade, it hits the floor, at which point the gun caps around the steel sphere hit the shell, which makes a spark, which makes the explosive gas detonate, which makes the whole thing explode. However, one problem killed the whole design: the explosive gas slowly leaked from the grenade, which was not completely airtight since it was 3D-printed. The Second Prototype Above is a photo of the second grenade prototype I made a few days ago (without the steel sphere or the explosive). This prototype consists of the following: A shell consisting of 8 tiny spikes with gun caps superglued on them, which hold the sphere in the center. A `15mm` steel sphere which sits in the middle, ready to hit the gun caps to make a small spark. Explosive powder that fills the shell (eg. black powder, flash powder...) which will detonate when the gun caps make a spark. This prototype is very similar to the first one, but it has one key difference: it can use a solid explosive, like flash powder. Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and if confined produces a loud noise. Wikipedia The idea is that the flash powder fills up the whole grenade, and it explodes when the steel sphere in the center hits a gun cap. There was only one problem: if the shell was more than half-filled with explosive powder, the steel sphere wouldn't be able to move at all, which means that the gun caps would never make any sparks. However, I still wanted to try it out, so I filled a quarter of it up with match heads, and then went outside to see if the ignition mechanism would work. Here is the demo, but keep in mind that I used match heads (which burn) instead of a real explosive (which actually explodes): youtube And here's a macro photo of the insides after the "explosion" (if you can even call it that): The Third Prototype Above is a photo of the third prototype I made (without the steel sphere or the explosive). It is very similar to the second one, consisting of the following: A shell consisting of 8 small spikes and an inner plastic sphere with gun caps superglued between them. A `15mm` steel sphere sitting inside the inner plastic sphere, ready to hit it in order to set off the gun caps. Explosive powder that fills the shell (eg. black powder, flash powder...) which will detonate when the gun caps make a spark. The advantage of this prototype over the second one I made is that the steel sphere can freely move inside the grenade (inside the inner plastic sphere). The steel sphere is not in direct contact to the gun caps, but that is not a problem since the inner plastic sphere is very thin and flexible. When the steel sphere hits the inner plastic sphere, it sets off one of the gun caps, which in turn sets off the explosive powder. I also did a test by replacing the explosive for match heads, and it worked perfectly! Here is a picture of the grenade after it had caught fire: Unfortunately, I have not decided which explosive powder I will use yet. As soon as I figure it out, I will make an update to this post so you can see the grenade explode for real! See you there!
© 2025 Emilien Breton `legacy/DIY-Grenade/index.md`

DIY Grenade

Taking you through the 3 prototypes I made for my DIY grenade, and sharing my thought process with you! 2020-06-27

The Idea

About a year ago, I wanted to try to build a small grenade. I have no idea what made me want to build it, but it wasn't to harm anyone. I simply wanted to see if I would be able to make one to learn a bit more about how 3D printing and contact explosives worked.

Unfortunately, I couldn't find any remanence of the first design I made. The only thing I remember is that I knew it wouldn't work before even printing it, so I decided to give up on the project. However, a few moths ago, I decided I would give another go at this project. Here is a list of the prototypes I made before arriving at the final version:

The First Prototype

first grenade prototype

Above is a photo of the first concrete prototype I made, about 4 months ago. How it worked is very simple. It consists of the following components:

A hollow 20-face shell (an icosahedron) which is made to rip apart into 20 sharp triangles when the explosive detonates.
A 15mm steel sphere with gun caps all around it that make a spark when they hit the outer shell.
Some explosive gas (i.e. hydrogen) that fills the shell, which is menat to explode whenever the gun caps make a spark.

Long story short, after one throws the grenade, it hits the floor, at which point the gun caps around the steel sphere hit the shell, which makes a spark, which makes the explosive gas detonate, which makes the whole thing explode. However, one problem killed the whole design: the explosive gas slowly leaked from the grenade, which was not completely airtight since it was 3D-printed.

The Second Prototype

second grenade prototype

Above is a photo of the second grenade prototype I made a few days ago (without the steel sphere or the explosive). This prototype consists of the following:

A shell consisting of 8 tiny spikes with gun caps superglued on them, which hold the sphere in the center.
A 15mm steel sphere which sits in the middle, ready to hit the gun caps to make a small spark.
Explosive powder that fills the shell (eg. black powder, flash powder...) which will detonate when the gun caps make a spark. This prototype is very similar to the first one, but it has one key difference: it can use a solid explosive, like flash powder.

Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and if confined produces a loud noise.

Wikipedia

The idea is that the flash powder fills up the whole grenade, and it explodes when the steel sphere in the center hits a gun cap. There was only one problem: if the shell was more than half-filled with explosive powder, the steel sphere wouldn't be able to move at all, which means that the gun caps would never make any sparks. However, I still wanted to try it out, so I filled a quarter of it up with match heads, and then went outside to see if the ignition mechanism would work. Here is the demo, but keep in mind that I used match heads (which burn) instead of a real explosive (which actually explodes):

youtube

And here's a macro photo of the insides after the "explosion" (if you can even call it that):

second grenade prototype after explosion

The Third Prototype

third grenade prototype

Above is a photo of the third prototype I made (without the steel sphere or the explosive). It is very similar to the second one, consisting of the following:

A shell consisting of 8 small spikes and an inner plastic sphere with gun caps superglued between them.
A 15mm steel sphere sitting inside the inner plastic sphere, ready to hit it in order to set off the gun caps.
Explosive powder that fills the shell (eg. black powder, flash powder...) which will detonate when the gun caps make a spark.

The advantage of this prototype over the second one I made is that the steel sphere can freely move inside the grenade (inside the inner plastic sphere). The steel sphere is not in direct contact to the gun caps, but that is not a problem since the inner plastic sphere is very thin and flexible. When the steel sphere hits the inner plastic sphere, it sets off one of the gun caps, which in turn sets off the explosive powder. I also did a test by replacing the explosive for match heads, and it worked perfectly! Here is a picture of the grenade after it had caught fire:

third grenade prototype after it caught fire

Unfortunately, I have not decided which explosive powder I will use yet. As soon as I figure it out, I will make an update to this post so you can see the grenade explode for real! See you there!