How to make your own "PUT-PUT BOAT" or "POP-POP BOAT"


THIS page is for the larger, METAL boat.

The first, smaller, milk-carton boat page lives at

I strongly recommend that you go to that other page FIRST and make one with those instructions. THEN come back to this page and try your hand at it. It will give you the practice you need for this one.

I tried some 24-gauge aluminum but found that too thick. Now I use some "aluminum flashing" from Home Hardware; it comes in rolls 9 inches wide and costs me 99 cents per lineal foot. I suspect it is about 25 or 26 gauge.


Note that the measurements are in centimeters, not inches. One cm = .394 inch; one inch = 2.54 cm.

Here is my second metal boat:


I started this one with a piece of 26 (?) gauge aluminum (for you Englishmen, that's aluminium) measuring 30.4 cm x 36.

NOTE: I like to use J-B Weld for these projects. It holds very well and can take an awful high temperature without problem. Just recently I learned that there is a "KWIK" version of J-B Weld. The package says it sets in 4 minutes. I bought some LePage "Speed set Epoxy syringe glue" but it is awful stuff. The syringe is impossible to figure out (not only my opinion) and when you finally do get it going, it leaks all over the place with dire consequences. PLUS it is way too expensive. On top of that, the stink is incredible! Believe it or not, I actually had to throw the WHOLE THING INTO THE GARBAGE without being able to use ANY of it!! Talk about CRAP, YIKES!

I keep a package of wood coffee-stir-sticks handy; only $1 at the dollar store; comes in handy. Also, KEEP the little scraps of aluminum; they come in handy too; like for scraping up a bit of mixed J-B Weld.

And please, re-cycle the leftover scraps of metal and paper.....!

WARNING: This neat project requires parental guidance.

THIS IS VERY NECESSARY and that's a GOOD thing because parents and grandparents will enjoy this as much as the younger folks!

- WATER: danger of drowning
- RAZOR BLADE: danger of injury
- CANDLE: danger of fire
- POWERFUL GLUE: danger of sticking things better left un-stuck

Video Clip:

You can see a short clip (and HEAR the sound!) of my milk-carton boat; it is on my other page at

A few definitions:

"gunwale" is the top edge of the sides of the boat
"bow" is the front of the boat
"stern" is the back/rear of the boat
"transom" is "The stern cross-section of a square-sterned boat."

But you KNEW all that.

I've put a LOT of effort into this page; I'd like it to be as close to "perfect" as possible. IF YOU see any errors or room for improvement, please let me know; thanks!

This is a FUN project; not only does the little boat have POWER, but it SOUNDS like it has a tiny DIESEL motor!

This is not something you are likely to start one afternoon and finish by dinner-time. Expect to take a day or two, working on it a bit at a time.

It is a good educational project for young folks too; teaches about steam power.

You might have seen all kinds of websites about Put-Put Boats. I saw it on the Discovery Channel so I Googled it and, being retired, I thought it might be a neat little project. So I made one. Now I'm so enthused about it that I want to share with you how I make mine. They called by many names: "pop pop boats" or "pop-pop boats" or "put put boats" or "put-put boats" or "tuk tuk boats" or "candle boats" or "putt putt boats" or "putt-putt boats" or "puttputt boats."

I'm really enjoying making many of these boats and this page will evolve as better ideas come to mind.

The Patterns:


Note the deck; it is supposed to be two pieces; front and back but the hole in the back part is very difficult to cut. To get around that problem, I cut the back part of the deck into two pieces; "C" and "D." This made it possible to cut the hole out. To put the rear deck together again, I cut two little "patches" (see "E" below) and will glue those on to re-join C and D. The hull was too large to fit on one sheet so it is on two sheets.


Here is how I managed to get all the pieces onto the smallest piece of aluminum possible. Note the small, sharpened nail with rubber on the end. I use this to put through the paper into the aluminum at all the points and then I remove the paper and connect the pin-holes with a pen on the aluminum. It helps if you tape all the pieces together so you can remove all of them "in one piece" so it is easier to refer to it and see which pin-hole is which.

The two patterns on the right, not on the aluminum are, of course, not cut from that aluminum. The windshield is cut from clear plastic and the other part from a beverage can.


And here are all the aluminum pieces cut out.

A. boat hull

B. front deck

C. rear deck; part 1

D. rear deck; part 2

E. "patches" to re-connect C and D

F. cross-brace for the hull

G. the 2-part keel

H. transom for the back end

I. rudder

J. "blocks" to hold the boiler

K. "spacer" to go between the transom and rudder

L. two tiny circles cut from scrap, to be rolled around a pen


Most of the parts. Part E is 13 cm long and each of the two parts is 9 mm wide. YOU MAY PREFER to shorten the "E" parts a little. The long side of the transom ("H") is 11.2 cm and the short side is 9.6 cm; it's width is 3.5 cm. Note that part K, the rudder spacer, WILL need to be trimmed some.


The hull or body of the boat.

Make a mark with your felt pen, in the center of the stern, on the floor of the boat; you'll need it later.


The front and rear decks.

Note that this is BOTH front and rear decks and they are SEPARATE.

Note that the big "hole" in the rear deck is hard to cut out. What I did was cut the rear deck into two pieces and then cut out that hole. I cut at the "x."



A good place to start might be to join the two sections which make up the keel; parts "G." I like to lay them on a piece of wax paper so they don't stick to my work surface. The two pieces of wood and the two C-clamps make sure they are very tightly together while the J-B Weld sets.


Now the keel. I happened to have four larger C-clamps that worked well.

I cut a piece of thin plywood to fit the inside floor of the boat and temporarily taped it into the boat, to protect it from damage from the clamps. Then I put the J-B Weld on the keel and TAPED it onto the boat underside and THEN put on the blocks and clamps. It wouldn't hurt to put some wax paper or similar between the wood blocks and the keel.


Next, take the "cross-brace" part F and make it into a triangular "cylinder" using J-B and tape to hold it.

On the gunwale, both on the inside and the outside, make a mark with a pen, 13 cm from the transom. This will help position the cross-brace.

NOTE the tip near the bottom of this page, entitled "That WALL."


Now, an exciting part: putting the hull together. Sand the inside edge of the bow; where the J-B Weld will hold the front together. Cut a piece of metal tape full width and long enough to tape the front from top to bottom. You can leave the stern of the boat open for now.

Put a thick "bead" of J-B on the inside of the bow and put on the tape. Then glue the cross-brace into position.

The top edge of the brace must be flush with the top of the gunwale. Here is the jig I used to keep it in place. The groove is plugged in the center so that the cross-brace does not move UP into that groove. The holes in the stick allow me to see the pen-marks in the hull. The stick is held in place with an elastic band which goes under the keel.


Now you can close up the stern. Leave the two small flaps on the outside. To do this, I made a wood "tool." See inset.

I find it best to glue the two tabs in place and when that glue has fully dried, add the transom part H, on the outside.

A bit of wax paper or similar prevents the glue sticking to the wood. It MAY be desirable to trim the transom before sticking it on.


When the transom is solidly in place, it is time to drill the holes in the stern for the two straw tailpipes. This might be the most difficult part of the whole project. You have made a mark on the transom showing where the exact center is. Now drill very tiny holes for the tailpipes. I use my high-speed rotary tool with a tiny pointed tool to enlarge the holes. This shows that tool.

Put a short piece of metal tape on each of the two rear corners of the boat.


THIS might be a good time to make a "stand" or "dry-dock" for your boat; it will be handy during construction.

This is my favorite, quickie design.

cutting the can

Now take your CLEAN soft-drink can and cut off the ends. A brand-new (one-sided) razor blade should be sharp enough to cut it. Then cut it down one side to salvage as large a piece of thin aluminum as possible. Avoid dents and creases. This should result in a piece of aluminum measuring 20.5 cm long and pretty close to 9 cm wide. Using a straight-edge, (ruler) cut one of the long sides perfectly straight. That done, fold this sheet of aluminum in the middle so you have it measuring 9 cm x 10.25 cm. Fold it with the printed side OUT. Lay this on a hard surface and press on the fold with your ruler to make that fold very tight, like this.
At the open end, put tape to keep it "together" for now.

Cut the can very carefully so as to get as large a piece of aluminum as possible.


cutting the can

If you are going to use a high-speed rotary tool with a "cut-off wheel" and the proper "mandrel" to hold that wheel, be SURE TO USE EYE PROTECTION!!!! If you do not, you will probably wind up BLIND forever. And if that happens, you will not likely ever SEE your boat in action. Using a wheel like this, as I did here, can provide a nice clean cut but you will have to use sandpaper on the sharp (!!) edges when done. This does allow a nice clean cut. I cut off the bottom first and before cutting off the top of the can, I rolled up some newspaper into a very tight roll to fit into the can snugly. This prevents it from crushing or denting when I cut the other end off. NOTE: when I tried to cut the other, heavier aluminum with this tool, the screw broke off inside the part that goes in the chuck.

boat engine

Tape the pattern for the boiler, onto the aluminum and cut out one piece. This should leave you enough aluminum to make a second one for your next boat. Save the aluminum scrap for now.

boat engine

Then mark on the aluminum, the edges to be folded; use a ballpoint pen to scratch the 2 lines onto each piece. That done, fold the edges over along a sharp edge such as the kitchen counter.

boat engine

Next, carefully bend the edges further and when they are bent far enough, lay the piece on a hard surface, remove the bit of tape which is still on the open end, lay a ruler on top and pound it once or twice with your fist to press the edges down. On this picture, the one on the left is done and the other has yet to be pounded down.

boat engine

Now make 4 tiny "Scotch Tape donuts" and stick them on the underside of the boiler, that is, the side which does NOT have the folded edges. Have your donuts big enough to stick to the aluminum, all the way across, from one side to the other. Take a piece of leftover milk-carton paper and stick the boiler on that for now. Press it down good and tight to the paper. Here, the one on the left has the donuts on it; the other shows the OTHER SIDE of a boiler.

I often use one long "donut" from Duct Tape.

boat engine

Now take the two flexible drinking straws. Each has a "short end," an "accordion-like" piece that allows it to bend, and then the "long end." Cut a short piece off each SHORT end so that there is only 2.5 cm of "smooth" straw left from the "accordion" to the end. Use sandpaper to "roughen" these 2.5 cm so that the J-B Weld will hold better. The end of the straw furthest away from the "accordion" will be the "Tail Pipe." Push both of the LONG ends into the boiler as far as they will go.

This is only TEMPORARY!

This will be awkward; you may want to push a sharp object such as a pencil into the boiler just a little bit, to open the end enough for the straws to go in. In this picture, I have cut the straws to make it easier to see that the bottom of the boiler should stay FLAT while the top is ROUNDED.

boat engine

Now mix up a BIG gob of J-B and apply it to the boiler to seal the sides well. Use that strip of scrap aluminum to get it between the layers of aluminum in the folded edges. Use lots; do NOT yet seal the end nor get any J-B on the straws. This step should do two things: 1. SEAL the boiler (sides only) 100% and 2. help it KEEP its rounded (on one side) SHAPE. This is an awkward yet important step (as they ALL are!) and one way you might use to get the glue in BETWEEN the layers of aluminum, is to pry them apart a tiny bit with your razor blade and then push in toothpicks to hold it open while you push in the glue.

boat engine

When that has fully dried, pull out the two straws and carefully remove the boiler from the Scotch Tape donuts. You have, earlier, used sandpaper to "roughen" the short ends of the straws, right? Now, mix up a large gob of J-B and apply it around the SHORT end of each straw, BUT, leave about 4 mm right next to the "accordion" with NO glue on it. Slide the straws into the boiler just so all the glued part goes in. Apply a generous serving of J-B all around where the straws go in, filling the end of the boiler so that it is completely sealed. Don't forget to put some glue in between the straws as well. Lay this down on something so that any drips of glue won't be a problem. Let this dry completely. Note the 4 (prox) mm of straw left between the glue and the accordion.


Now cut and bend the two little "blocks" (parts "J") like this; they will help position the boiler.


Slide the boiler with tailpipes unit in from the front, with the flat side underneath. It will be UNDER the cross-brace and up against it, touching it. Push the boiler in until the top end of it will be JUST BARELY lower than the gunwale so that the front deck can still close. Now mark the bottom of the boat to show exactly where you need to glue the blocks part J. Glue the two little circles, part L, on the inside of the gunwale, up against the front of cross-brace F so that they are as high up as possible without getting in the way of the front deck. Here you can see the two little circles and the two blocks.


When the blocks are in place and the glue is dry, re-insert the boiler with tailpipes like this, but FIRST, caulk the tail end well.

Put a LOT of caulking at the back of the boat, up the sides and across the bottom, with a BIG gob of it right OVER the two holes you drilled. You will trim about 8 cm off the tailpipes so whatever caulking goes into them won't be a problem. Be sure to get plenty of caulking UNDER the tailpipes at the transom too!

If you find it difficult to push the tailpipes through the two holes you drilled, make the ends of the tailpipes "POINTED" by cutting into the ends, rolling the plastic to make the diameter smaller, and hold it that way with a tiny bit of Scotch Tape.

Take a bit of wire and run it under the top end of the boiler and to the two little circles, to keep the boiler up against the underside of the cross-brace.

When the glue is dry, trim the tailpipes so that they are "just barely" sticking out of the boat.

Test your boat for leaks and propulsion/sound now. You may want some weight in the back as well.


Now re-connect the two parts of the rear deck, parts C and D, using the two "patches" E. It would be good to put the two patches on the UNDERSIDE so that any glue which "squishes out" won't make an ugly mess. Then, with metal tape, attach the rear deck to the FRONT of the cross-brace, and then attach the FRONT deck with TWO pieces of metal tape, to the BACK of the cross-brace. This way, both front and rear decks can be raised.


Making the windshield: here you see the pattern, the 3 pieces and the metal tape to hold the 3 pieces together and trim the edges.


Finally, make the rudder. Fold the end of the wire tightly and slide the rudder part into that fold and add lots of J-B Weld.

Cut your piece of straw to the length needed which is the distance from the top of the tailpipes where they come out of the stern, to the top of the transom but NO LONGER. Slide several pieces of straw or toothpick into the straw which holds the rudder wire, so that it takes a very tiny bit of "force" to turn the rudder. Trim part K as needed and then bend it to make a little "spacer" as I show here, so that the rudder shaft is not up against the transom. Roughen with sandpaper the straw part and glue it to that spacer. Make sure the spacer is NO LONGER than the straw is.

Bend the top of the wire in whatever way looks best to you and glue the spacer to the stern.


For a much easier way to make this spacer, I made this little tool. "C" is just a piece of 3/4 inch plywood with a groove in it; the groove is about 4 mm wide. "B" is another piece of 3/4 inch plywood with a groove in it (never mind the two grooves in the top) to hold a very small piece of 1/8" plywood which is "A." "D" is the piece of aluminum, pattern "K" which is to be folded to become the spacer for the rudder. After I press down on B to push A and D into C, I lay the other piece of aluminum, "E," on top of the partially-folded D, put "B" on that (upside-down) and press down to flare the sides as has been done here.

TIP: "That WALL"

Instead of using the cross-brace mentioned near the start of this project, you might prefer to make a "wall." Here is a diagram of it and a pic of it cut and folded, ready to glue into position, 13 cm from the transom.


Note that the bottom part is 4 cm wide. When I print this out with Irfanview, I set the measurements at 12.2 x 8.34 and center it on the sheet. The top part is bent simply to strengthen the wall and all 3 tabs are glued to the walls of the boat and the bottom. The boiler goes through the hole.


These metal boats are more likely than the paper boats, to sink. With that danger in mind, I like to glue several "foam packing peanuts" in the boat somewhere, well clear of where the candle flame will be. Here are three of my boats showing the foam.

If the front deck won't sit down onto the gunwale too well, just glue a weight under it.

THAT should do it. Happy Boating!

What's Next?

I'm working on a boat with a "V" bottom. I won't make a detailed web-page on that one but you can see some of the details at

Some Ideas:

1. Have a contest to see who can add the nicest paint-job to his/her boat.

2. At some little pond, put a target at one side and have the boats launched at the other side and see whose boat comes closest to that target.

3. Before you take your boat out to play with it, make several more "fuel supply" strips with candles glued on.

4. Have a contest to see whose boat goes fastest.

5. See who can come up with the "coolest" name for his/her boat.

6. Design your own; maybe these free boat plans will help:

7. When you have completed building a boat, put a note on the underside of the roof, with your name, boat number and date of manufacture.

8. Have a contest to see whose boat will run for the longest period of time.

9. Have a contest to see whose makes the loudest PUT-PUT sound.

10. If you are going to some outdoor pond with your boat, take a fishing rod with very fine line, and a small piece of wood tied at the end. That way, if the boat stalls in the middle of the lake, maybe you can cast the wood over the boat to drag it back.

11. Keep in mind that water may continue to drip out of the boat for quite some time after use, so be cautious as to where and how you handle it.

12. You should not have the candle flame too close to the straws; even inside the "steam chamber" they can easily melt.

shopping bags

13. To take a number of boats safely to the lake, without damage, put each boat into a shopping bag and hang all the bags on a coat hanger. Then just hang the coat hanger in your vehicle, like this.


14. Maybe a more efficient way to ensure a good supply of "heaters" (see step 10, above) would be to glue on the ends of some foil strips, VERY short pieces of drinking straw, big enough to hold the candle. Then you could, out at the lake, just stick in a new candle and you would not have the problem of having to glue the candle on. See mine:


This is my fleet as of April 15, 2008; some metal, some milk-carton paper. One with V-bottom.

At this point I had given away four.

Resources on the web:

And there is a forum at

how to get Diamond Willow

in fact, tell EVERYBODY!

Diamond Willow Sticks

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