The materials you need are all readily around the house or you have to scrounge them from some professional outlets. The wire for the “piston rod” is cut from a coat hanger. Use pliers cut off the longest length from the bottom of the hanger. Then bend one end over and make a small eye as a stopper.
Corks are getting scarce since most wine bottles, for example, come with screw lids. But you can get corks at the amateur wine making stores or we are sure you can find some corks still around the house or at your friends’ place.
You need one washer that has a small hole to fit the wire, but those are not easy to come by. We used a small and larger washer, the small one locks-up the piston at the bottom, the larger washer supports the rubber piston. the larger washer is about 19 mm in diameter.
Note the larger washer should have a diameter a little smaller than the inside diameter of the tube, or “cylinder”.
The tube is a piece of electrical plastic “three quarter” conduit, it has an inside diameter of about 21 millimeter. You can use any saw to cut the tube to a lenght of about 30 cm. The tube or cylinder should be shorter than the length of the wire you cut from the coathanger.
You need a marble for the “foot valve” and a piece of rubber hose about 2 centimeter long that fits into the tube or cylinder.We used “1/2 inch” water heater hose, that you can scrounge from a garage or at any automotive supply store.You can cut it with a box-cutter or sharp knife, get some help and be careful!
The pump outlet is a piece of clear plastic hose, about 8 mm in outside diameter, you can buy that by the foot or 30 cm length minimal at any hardware store. If you ask for a smaller piece or sample you might get it free!
The black rubber piston is made from rubber flat-roof lining, it is about 2 mm thick and any building supply company sells it 3 meters wide and a minimum of one foot. But ask for a sample and … You can also use flexible leather. You have to cut a circular piece that is perfectly round and fits tightly in the tube or cylinder. We stamp it out with a steel tube that we have filed into a sharp edge at one end. But you can use a compas to mark a circle on cardboard and cut that, check the size and then cut the rubber or leather with the cardboard circle as a template. The steel tube is just the same size as the plastic tube, we show it on the photo, the flange at teh top results from multiple hammer blows using it to stamp out the rubber or leather pistons. Both the plastic and steel tube you can get from the electrical supply company, or from your friendly neighborhood hardware store or electrician. Electricians have bits and pieces of plastic and steel tubing that they are more than willing to share with you when you explain you need them for a science and technology project!
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