A- Displacer - Aluminum drink can with top and bottom cut off. The can is cut vertically and glued (with hi-temp epoxy) together to form a 1-1/4" high cylinder with a diameter of about 95% of its original diameter. When the can is glued to form a cylinder, the overlap will be about 10 millimeters (assuming a 65 mm diameter can). The bottoms of 2 aluminum drink cans are trimmed to just fit inside the displacer and are glued into place (one end dish side in, the other end dish side out). There should be no air leaks into the displacer. The displacer should be smooth and fit inside an aluminum drink can (pressure vessel) with about 2 millimeter clearance when centered inside the can.
B- Displacer rod - 2 inch straight quilting pin
C- Pressure Vessel - Aluminum drink can with top cut off - 2-1/2" tall.
D- 1" x 1/4" Copper tube (or equivalent). You can also make a tube by rolling a section of aluminum cut from a can into a tube and gluing the seam. Remember the seam must be air tight.
E- 3/4" Schedule 40 PVC Cap (about 1.125" inner diameter)
F- Flat Washer - 1/4" tube should just fit inside the washer hole
G- Rubber diaphragm cut from a helium quality balloon. The diaphragm should be cut from a spherical portion of the balloon so that it is dish shaped.
H- Pressure Vessel Top - Aluminum drink can bottom, dish side down. Top should be about 1 inch tall. An 1/8" hole should be punched in the center. Epoxy (high temp) a 1/8" long section of 1/4" copper tubing (or equivalent) over the hole. Cut a flat 1/2" square out of a steel can (I used the bottom of a peanut can). Note that the 1/2" square must be made of steel. Punch a hole in the center of the flat square with a straight pin. The displacer rod should slide smoothly through this hole with no side to side movement. This is intended to be a fairly air tight seal; although there will be some air leakage. Epoxy the square onto the copper tube. The hole in the square should be centered over the hole in the pressure vessel top (see sketch).
I- Crankshaft Supports - Cut out four 1-1/2" x 4" sections from an aluminum drink can. Make a pair of supports by gluing (with high temperature epoxy) two sections together for stiffness. Punch a hole in each support 1/2" from one end. The hole should be just large enough to allow the crank to turn freely; but there should be no up-down or side-to-side play in the crank.
J- Flywheel - 2 AOL CDs glued back-to-back (shinny side out).
K- Penny (2 total) with hole drilled in center. Hole is sized to allow the crankshaft to be inserted. Pennies should be centered over the flywheel and glued in place. Holes in the pennies should be left clear so that the crankshaft can be inserted. Crankshaft will be perpendicular ot the flywheel.
L- Connecting Rod - Stiff aluminum wire. One end of the wire will be coiled around the crank. The other end of the wire will be glued (with super-glue) to the rubber diaphragm (see sketch).
M- Connecting Rod - Stiff aluminum wire. One end of the wire will be coiled around the crank. The other end of the wire will be coiled around the displacer rod (see sketch).
N- Crankshaft - Stiff coat hanger wire (or equivalent). Bend per sketch.
O- Fire Box - Aluminum drink can with top cut off. Remaining can should be 3-1/2" tall.
P- Base - 6" x 6" x 1" wood