How to Make a Bottle Cap Pressure Relief Valve

We only need this portion of the valve. The reducer and the ball inside. Inside, there is a small ball. Cut carefully to prevent the ball from going out. After cutting this portion, we will cover
it with glue but we will leave a small hole for the gas to release but not too big for
the ball to escape. While waiting for the glue to dry out, we
will now cut the hole on top of the bottle. Shake the ball inside and check if it can move freely Then we will place this inside and seal the
sides with glue. Place it aside and dry it out for few minutes. After drying it, shake it and you should hear
the sound of the ball bouncing inside.


  1. The way that large knife was handled made me anxious. One slip and you could lose your fingers. Better off just piercing the cap with something pointy and a tap from above.

  2. Very helpful on a basic design. Thanks for making a video on this.
    I love how the knife got bigger and bigger

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