Milled water bottle rocket launcher pushes plastic containers to their limit

water-bottle-rocket-launcher

Building this launcher is simple if you already have a mill. It does a remarkable job of pressurizing and launching soda bottles which are partially filled with water. The main component of this is a triple-gasket stopper with a quick release.

The problem with a lot of these water bottle rocket projects is that they leak where the bottle meets the launcher. In most cases this is a good thing as it’s almost impossible to build up enough pressure to cause the bottle to fail. This system has no such built-in safety mechanism, which is why the test launch below is conducted from a safe distance. After seating the partially filled bottle on the launch platform it’s pressurized to around 100 PSI at which point a yank on the string lets it fly.

Most of the time we look on these as casual projects. But we figure this one is much more suited for a rocket club or hackerspace event.

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Plastic bottles funnel rain into rain barrels

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This is [Wombling's] no-cost solution to getting rain from his gutters into a rain barrel. It is literally just a bunch of plastic water bottles chained together. At one end he uses the original cap with some holes punched in it as a sieve.

We like the concept, but find the execution a bit dubious. In heavy rain the holes in the cap will not be able to keep up and we figure your gutters are going to overflow. That may be okay depending on the grade of your landscaping, but those who value keeping their basement dry should avoid this route.

Just a bit of improvement could change all that though. We suggest making the rain barrel the sieve. Add a bowl shape to the lid with a large piece of screen in the bottom to filter out debris. Then form some type of spout on the front side of the lid to channel overflow away from the house.

The amount of waste generated by bottled water has always troubled us, which is part of the reason we featured this. We also liked seeing those plastic bottle skylights, and could swear we featured a floating plastic bottle island built in the ocean but couldn’t find the link. If you know what we’re talking about leave the goods in the comments section.

Acoustic bass guitar uses water jug and two strings

water-bottle-acoustic-guitar

It’s easy to dismiss this one at first glance. But once you hear [Tychsen81] playing the thing you’ll want to know more.

He posted the demonstration way back in 2009. It wasn’t until a year later that he filmed the particulars of how the thing was made. The strings are actually bass guitar strings, an A and D string that are tuned down to E and A to play along with Black Sabbath’s “Ironman”. The neck is made out of two boards. One serves as the fingerboard, which is fretless. The other is mounted under that in order to provide negative space for the bridge while keeping the strings at the right height for the fingerboard. The water bottle helps to amplify the sound and that’s why the bottom end of the strings pivot on the bridge, pass through the neck, and are anchored on the bottom edge of the bottle.

We’ve embedded both the demo and the build videos after the break.

If this gets you thinking about making your own instruments you will also be interested in the Whamola.

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