How To Make Putt Putt Boat or Pop Pop Boat
I go into detail about what makes the steam engine work in the explore page. But before you begin making the engine, you should at least have some idea what you're about to do. It is deceptively simple looking.
After cutting the top and bottom off an aluminum soda can, you will fold the middle part into a rectangular "pocket", creased shut on three edges and open like a pocket on the fourth edge (the blue part in the illustration at right). The top side of this flash boiler--where droplets of water are heated into steam--is arched, the bottlom flat. The flat bottom flexes like a canning jar lid, which gives the boat its distinctive sound. Into the open fourth edge of the boiler you insert the ends of two flexible plastic straws (green in the picture). The whole thing will be glued and sealed airtight with quick set epoxy glue and silicone rubber caulk. Between two of the gluing steps you will have to wait about 15 minutes, and overnight for the last. During that time you can create the body of the boat from milk cartons, make a candle holder, and read ahead to the next steps.
Some of the following instructions might sound weird and finicky. I try to explain the "why" of the steps, but in the end you'll have to trust me that each detail is important. Do the first boat my way and get a boat that works. Then you can innovate and experiment.
Materials:
Soda cans, 12 oz. 355 ml
A cut up soda can forms the boiler of the steam engine. The water/steam pushing in/out of the boiler bulges the aluminum several times per second. This also gives the engine its cool sound. The process is similar to when a canning jar lid is pushed to make a noise, though the sound is different.
Important: The soda can must not be dented. Have several on hand to start over when you make errors. Rinse out the sticky soda inside.
Plastic, flexible drinking straws, approxamately 193mm long by 6mm diameter (7 5/8" by 1/4")
The straws become the jets from the engine.You ought to be able to get these at a grocery store where the beverages or paper cups are. You can also get them in department stores. There is a slightly thinner kind imported (usually from Thailand) and that works, too.
Quickseting or 5-minute epoxy
Epoxy is a very strong, two-part (which you mix together) adhesive actually used to glue real jet plane parts together. You will use it to seal the boiler airtight and glue the straw exhaust pipes. You can get it in any hardware store and most building centers. Important: Whatever the brand, get the kind that indicates that it sets fast: 5-minute, quickset, etc. or you will be waiting long periods between steps for it to harden. Even 5-minute epoxy only begins to thicken in five minutes. It takes at least 15 minutes to attain most of its strength. Putting the mixed epoxy in a warm place makes it set faster. Usually it comes in a double syringe which will help you dispense it evenly.
Although you cannot accidentally glue your fingers together the way you can with "super glue," epoxy is extremely messy. I try to keep it from getting on my hands in the first place (I never completely succeed). To get it off, I wipe as much off with a dry rag first, and only then try to get the last bit off with soap and water. By the way, epoxy smells like a moldy tuna fish sandwich.
100% silicone caulk/bathtub sealer
The silicone does two useful things. First, a thin layer of silicone spread over the epoxy seals hidden leaks. Even a pinhole leak can keep an engine from working, so silicone can gives you an extra layer of insurance. Because it is flexible, it maintains the seal even when bumped enough to crack epoxy. Secondly, though I mentioned that epoxy smells, high temperatures (such as those found at the boiler) really make it stink. So that same layer of silicone that seals hidden leaks also seals in the epoxy smell. Silicone also helps to make the candle holder.
You can buy silicone where you get the epoxy. If you don't need it for other things around the house, you can get a little tube of it since this project will only use a couple of dabs for each engine. If you get the 300ml cartridge pictured, find out how to use it and the dispenser. You have to cut off the tip and poke to puncture the seal at the other end of the tip. A nail stuck into the tip keeps the silicone from clogging when not in use. Don't get a mix of silicone with anything else. It has to be 100% silicone. It smells like vinegar as it cures. It cleans off like epoxy, above.
Utility knife (or any sharp-tipped knife or single-edge razor), good scissors, ball-point pen, pencil, tape, and a ruler (or at least a straightedge).
You will use the scissors to cut up the aluminum soda can. This will not harm the scissors. Although I show clear tape in the illustration, masking tape is better: stronger yet easier to remove.
juice or milk carton(s)
This is make the body of the boat. The cardboard from beverage cartons is waterproof, easy to cut and can be painted. In the U.S. a standard size is half gallon, or 1.819 liters. I think a similar size would work. You will need a second carton if you make the top of the boat.
aluminum foil and birthday candles
This is the stuff that is not actually the engine. You will only need a 4" strip of aluminum foil from which you make the candle holder. The birthday candles are available in department stores and grocery stores.
You can watch the video below for more information.Besides that, you can download it.
Bunkface-Through My Window.mp3
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