How to Make a Stirling Motor

• 1). First you will create the displacer or piston for your Stirling motor. Take one of your aluminum cans and cut the top and bottom off. Then cut the can from top to bottom so you can roll it into a cylinder. The cylinder you are making should fit inside an aluminum can with only a 2 mm clearance. Cut this cylinder so it is only 1-1/4" in height. Use Super Glue to glue the cylinder; the lap of the metal should be about 10mm in width to fit correctly.
  
  Next, cut two circles out of the discarded ends of your can that will fit in each end of the cylinder so that it is completely sealed. Glue the ends into place.
  
  
• 2). Create your diaphragm next by cutting it from the bottom of the balloon so it retains a dish shape and can fit inside an aluminum can.
  
  
• 3). To make your pressure vessel, cut the bottom off an aluminum can so it is about 1" in height. Punch a 1/8" hole in the center. The dish side of the bottom of the can should face down. Use the RTV epoxy to affix a 1/8" piece of the copper tubing over the hole.
  
  Now cut a flat ½" square out of one of your discarded pieces of can. Using the straight pin, put a hole through the center of the square. The quilting pin should be able to slide through this hole without moving side to side. Epoxy this square with JBweld applied with a toothpick to the top of the copper tubing.
  
  Use the JBweld and epoxy the square of metal directly over the hole in the aluminum bottom with the dish side still facing down and away from the copper tubing.
  
  Use pieces of Scotch Tape and Super Glue to hold the metal pieces together as they dry.
  
  
• 4). Your crankshaft is the next thing you will make. Take the wire coat hanger and open it so it is straight. Working from left to right, bend it so the first section is straight (about 4"), then bend a 90-degree angle toward you. One inch from that bend, make another 90-degree angle so the wire now runs down. 1 inch from that bend, put another 90-degree angle so the wire is running again to the right. One inch from that bend, place another 90-degree angle so the wire is running up. One inch from that bend, do another 90-degree angle so the wire is running away from you and, finally, place one last 90-degree angle so the wire is running to the right. Cut the wire so the last section running to the right is about 4" long.
  
  
• 5). To make the crankshaft supports, cut four 1-1/2" x 4" pieces from an aluminum can. Glue two of pieces together with JBweld to make one stiff support--do this for each side so you have two stiffened supports. Drill a hole just large enough to pass the crankshaft through about ½" from each end.
  
  
• 6). Take your two CDs and glue them together so the shiny sides are turned out.
  
  Take your two pennies and drill a hole in the center of each large enough that your crankshaft can pass through. Glue a penny over the centers of your CDs on each face. This is your flywheel.
  
  
• 7). Now, take the displacer you made and use the RTV epoxy to glue the quilting pin in the center. Insert this, dish side down, into your pressure vessel. The pin should stick out of the hole about 2½" and the displacer should be able to move freely within the vessel. Glue this assembly to the top to the vessel. Let the glue set and then bend a 5/16" section of the pin (not at the plate) in a 90-degree angle.
  
  
• 8). Drill a ¼" hole in the side of the PVC so the copper tube can fit into it. Epoxy the copper tube to the PVC cap with JBweld. The end of the tube that is attached to the flat washer should be place through a hole in the side of your pressure vessel and epoxy this into place.
  
  
• 9). Now you can put all the pieces of your Stirling motor together. Cut the top off another aluminum can so that the remaining can is 3-1/2" tall. This is called your firebox. Punch a small hole in the bottom of the firebox, center the bottom of the firebox in the center of the wood piece and use the wood screw to attach the two (putting the screw through the hole you punched).
  
  Put ½" of plaster of Paris in the bottom of your firebox, make sure the top of the plaster is even in level. When the plaster of Paris has dried, cut a slot in the side of your firebox large enough so you can slide the tea light candle through and onto the plaster bottom.
  
  Push the pressure vessel assembly into the top of the firebox about a ¼".
  
  
• 10
  
  Put the flywheel onto the crank, then use small pieces of the heat shrink tubing on either side of the flywheel as spacers between the crank and supports. Bend the end of the crank to 90 degrees. Install the crank in the support holes. Epoxy the supports to the side of the pressure vessel. The holes in the supports should be about 2.5 inches above the top of the pressure vessel.
  
  Super Glue the rubber diaphragm over the PVC cap so it is air tight but loosely fitted. Using your stiff aluminum wire, wind one end around the crank and glue the other to the center of the diaphragm, making the wire long enough so that when you turn the crank, it pulls the diaphragm but does not make it taut. Use another piece of wire and coil one end around the crank and the other around the displacer.
  
  
• 11
  
  Finally, light the tea light candle and insert it into the pressure vessel. Pour a small amount of water on the top of the vessel. Wait about one minute and turn the crank. The engine will begin to run and take over the motion from you.