This is a mini concrete vibrator that I use to aid in small scale concrete projects. It is very simple to make, and is also very effective.

Wet concrete is generally very viscous and can be difficult to work with as a result. Vibrating the concrete mix is an easy way of turning thick goopy concrete into flowing runny concrete that can be poured, spread, and used to fill cavities. In addition, vibrating concrete allows trapped air bubbles within the concrete to make their way to the surface, resulting in denser, stronger concrete.

It is based on a cheap and common battery powered pocket fan. The head of the fan is removed and replaced with a shaft collar that acts as on off-center weight. When the motor is at speed, this causes vibration.

Step 1: What You Will Need

1. A battery powered pocket fan

2. A shaft collar designed to fit a larger shaft size than the fan shaft. A quick google search for "Shaft Collar" should bring up plenty of matches. Below are some links to where these can be purchased online:

http://www.homedepot.com/p/The-Hillman-Group-3-4x1...

http://www.robotmesh.com/vex-robotics/motors-and-g...

http://www.bearingboys.co.uk/CABU10Z_-_10mm_Shaft_...

3. A screwdriver (or allen key, depending on the shaft collar)

Step 2: Pull the Head Off the Fan

The battery powered pocket fans that I have seen all have removable heads. You can just pull them off.

Step 3: Attach the Shaft Collar

Simply screw the shaft collar onto the shaft. The collar inner diameter needs to be larger than the fan shaft diameter, which means that when it is screwed onto the fan shaft, it will be off-centre. This off-centre weight is what will make the vibrator work.