I was making a water rocket. The way I build them is by splicing and making rosin couplings one as a time and testing them. Then I make another one. I tested this one up to 100 psi before and launched it at 70 psi before the failure happened. It failed at only 40 psi. This was a normal launch, so there was about 2 1/3 L of compressed air. The splicing failed. Unfortunately, I didn't get a video of it exploding. I've learned a few things from this experience.
1.Neighbors don't like loud sounds
2. Always film what you are doing
3. Fix leaks (I think the cause of the failure was because there was a tiny leak in the splicing and I was too lazy to fix it
4. 40 psi is a lot of power(see pictures)
5. Get ear protection(I estimate at 100-120 db)
6. Put on payload at last second