Pop-Pop Boats
Pop-pop boats were a toy popular in the 1920's or so and are simple steam
powered toy boats. Yep, steam. I first learned about these little wonders
from the rec.crafts.metalworking newsgroup and the
Pop-Pop pages.
I set out to build my own pop-pop boat but ran into several problems along
the way. First of all, copper flashing is expensive as you have to buy it in
rolls sufficient to build an armada of these little boats. Second I
couldn't find 1/8 inch copper tubing anywhere. I tried the automotive stores
and all I could find was plastic tubing. About this time I received a
commercial pop-pop boat for Christmas. I started to play with this one and
thoughts of making my own went on hold.
This boat was made in India and imported by
Grahamco Trading.
All in all about what I would expect from Indian metalworking. My boat had
some problems that I had to fix before it would run. The "boiler" on my boat
had leaks where it was soldered to the tubes that run to the back of the
boat. I re-soldered these and fixed the leaks. Let me tell you, re-soldering
these was a challenge. The entire boiler is soft soldered together so you
have to be fast or you melt the solder that holds the whole thing together.
The cover to the boiler is very thin brass and I poked at least one
hole in mine trying to hold onto the thing with pliers. Luckily I could
solder my error shut. Finally there in almost no room to get an iron on the
boiler when it is aligned with the tubes in the bottom of the boat. I did
manage to get all the leaks patched and the boat does indeed run, although I
found I have to leave the cover off or the flame goes out due to lack of
air.
At some point in all this I did find some 1/8 copper tubing lying about in a
scrap pile on campus. I was half way to making my own pop-pop boat, but I
still couldn't find a small quantity of copper flashing for the hull. I kept
looking but was getting impatient. One evening I got bored and took notice
of a nice anchovy tin in the pantry. I realized that it would make a nice
ready made hull for a pop-pop boat. Now all I had to do was get rid of the
salty little fish residing in my hull. A day later I had talked my roommate
into eating the anchovies (I ate my share too... the sacrifices I make...)
and I was on my way.
Here we can see the boat I built. The hull is the above mentioned anchovy tin,
the boiler is 1 1/2 turns of 1/8 inch copper tubing, and the burner is a bottle
cap with some 12 ga. solid copper wire for a handle. I discovered that
anchovy tins are now made from plastic coated aluminum and not solderable.
This led to a minor mounting and sealing crisis. The boiler was mounted to the
hull by tying it down with 20 ga. solid copper wire. All holes through the
hull were sealed with bees-wax. I was a bit concerned about the bees-wax
melting in operation, but the aluminum hull makes an adequate heatsink and
melting has not been a problem.
The moment of truth was the first firing of the little ships boiler. I
flooded the boiler with water and placed the vessel in the "harbor" (a
skillet filled with water. Hey, the sink was full... besides the round sides
let the little ship run in circles). The burner was filled with a dollop of
Sterno and lit. Nothing. It just sat there. Then there was a slight
quivering of the water at her stern. It started to move forward. Success!
Little did I know that this was just be beginning of the show. The little
ship picked up speed and cruised silently around the skillet for a while.
Then she got up to full steam and did something amazing. Ever seen an
anchovy tin on plane? I have. It is a sight.
I have to say that I am pleased with my little boat, but there are a few
things that I would do differently next time. First, the weight of all the
copper makes the boat a little stern heavy. I think that I would put the coil
of tubing and the burner in the bow of the boat to try to redistribute the
mass a bit. Second, the boats speed varies as the flame is blown off the
boiler by the boats forward motion. As the boat slows down, the flame
returns to the boiler and the boat picks up speed, and the process repeats.
I would include some sort of wind break and / or chimney to prevent this
problem. A rudder might be a nice addition for the boat if I intend to ever
take it out of the "harbor" in the kitchen.
back one level
This boat was made in India and imported by
Grahamco Trading.
All in all about what I would expect from Indian metalworking. My boat had
some problems that I had to fix before it would run. The "boiler" on my boat
had leaks where it was soldered to the tubes that run to the back of the
boat. I re-soldered these and fixed the leaks. Let me tell you, re-soldering
these was a challenge. The entire boiler is soft soldered together so you
have to be fast or you melt the solder that holds the whole thing together.
The cover to the boiler is very thin brass and I poked at least one
hole in mine trying to hold onto the thing with pliers. Luckily I could
solder my error shut. Finally there in almost no room to get an iron on the
boiler when it is aligned with the tubes in the bottom of the boat. I did
manage to get all the leaks patched and the boat does indeed run, although I
found I have to leave the cover off or the flame goes out due to lack of
air.
