If you need a supply of low pressure air – let’s say enough pressure to ensure a constant supply but not enough to describe as “Compressed air” with a straight face – what do you do? Many people will reach for an aquarium pump, after all that represents a readily available and relatively inexpensive source of bubbles.
But not [truebassB], instead he built his own air pump from first principles (YouTube, embedded below) using PVC pipe. It’s a straightforward design in which the cylinder is a length of pipe with a disc of flat PVC glued to its end, and the piston is fabricated from a short piece of the same tube with a section cut out to reduce its diameter. An adequate seal is achieved using a piece of rubber cut from an inner tube, and the gudgeon pin is cut from a piece of wire. The connecting rod is another longer piece of wire, and the crank is a wooden disc with an offset hole. Power comes from a DC motor taken from a dead power tool. A couple of ball check valves are used for air input and output.
The resulting pump isn’t the prettiest of pumps, and it could probably do with a bit of balancing as it rattles somewhat. But it’s a pump, and it obviously cost next-to-nothing, so that in our eyes makes it a neat build. He’s posted a video of the build which we’ve placed below the break.