steam cannon

hi · Mon Apr 09, 2007 10:14 pm

I watched the mythbusters episode where they made a steam cannon. For those of you who didnt watch it, they managed to get a civil war era cannon ball a mile. i was thinking of how to build it. Thier smaller "test verion" was made out of copper and the fittings were soldered on. The way the cannon worked is the chamber had some water put in it, then it was sealed and heated up with 2 blow torches. When they got it to a couple hunded degees, they opened a valve (it looked like a ball valve or a butterfly valve). the steam was released into the barrel and a tenis ball shot out of the barrel.

I was thinking of making one, but i cant find any pictures. i have a few questions.

(1) how did they solder the copper pipe together and not have it melt when it was heated up?

(2) can a ball valve stand up to the 500+ degrees that it heats up to? if not, what kind of valve would?

(3) would it be safe if it had a pressure guage?

(4) would it be considerd a pneumatic cannon? it uses pressureized steam, which is gas.

paaiyan · Mon Apr 09, 2007 10:18 pm

They prolly didn't soplder, they welded.

Depends on what the valve is made of.

Assuming you have a big enough pocketbook, it'll be safe

I don't rightly know

iPaintball · Mon Apr 09, 2007 10:21 pm

If you can't weld the chamber together, use threaded pipes or braze it.

hi · Mon Apr 09, 2007 10:24 pm

i know they soldered it, i saw them solder it....

edit- i wasnt going to solder it, i was going to use threaded parts, but i was just wondering how they did it.

iPaintball · Mon Apr 09, 2007 10:25 pm

okay...

chaos · Mon Apr 09, 2007 11:07 pm

ball valves should be okay at that temp, at my work i have seen a 6" ball valve connected to a boiler which runs at temps 800+ im guessing a smaller valve should work at that temp.

Blitz · Mon Apr 09, 2007 11:24 pm

hi wrote:I watched the mythbusters episode where they made a steam cannon. For those of you who didnt watch it, they managed to get a civil war era cannon ball a mile. i was thinking of how to build it. Thier smaller "test verion" was made out of copper and the fittings were soldered on. The way the cannon worked is the chamber had some water put in it, then it was sealed and heated up with 2 blow torches. When they got it to a couple hunded degees, they opened a valve (it looked like a ball valve or a butterfly valve). the steam was released into the barrel and a tenis ball shot out of the barrel.

I was thinking of making one, but i cant find any pictures. i have a few questions.

(1) how did they solder the copper pipe together and not have it melt when it was heated up?

(2) can a ball valve stand up to the 500+ degrees that it heats up to? if not, what kind of valve would?

(3) would it be safe if it had a pressure guage?

(4) would it be considerd a pneumatic cannon? it uses pressureized steam, which is gas.

The whole thing, IMO, is unfeasable for us. What they accomplished with 500+ Degrees and water that couldn't boil instantly upon entering the chamber, AND with a valve between that chamber and the barrel, we can just do with just a valve and an air compressor... Archimedes didn't have a valve to work with, so the Mythbusters guys were trying to make a point (and of course, they busted the myth about his cannon).

They also flipped that valve with a pneumatic actuator (Not too cheap...).

hi · Mon Apr 09, 2007 11:29 pm

i was thinking more like, from back to front, cap, pipe, valve, reducer, pipe.

not that complex smarty pants...

and this would cost less than a pneumatic air cannon because,

(a) you dont need a compressor

(b) well, there is no B, but you dont need a compressor...

i have a compressor, i just wanted to make a steam cannon.

Blitz · Mon Apr 09, 2007 11:36 pm

And no, you don't need to use a compressor for a steam cannon (never said I did), but you need a LOT of heat to get your chamber hot enough to generate the steam/pressure necessary for a decent shot. For many people, that's a lot of hassle. Not to mention, using the cannon often will likely cost you a pretty penny in gas, depending on how you heat your cannon up.

locksmith · Mon Apr 09, 2007 11:38 pm

Hey why not try thats most of the fun is the build atleast for me

hi · Mon Apr 09, 2007 11:39 pm

here is a video that i found, mine would be different, but this gives you an idea of the power it has.

edit, here is a better one, it a shorter version that gets to the point faster

From_Hamsterdam · Tue Apr 10, 2007 5:06 am

If the ball valve is 500+ degrees how are you going to turn it?

I think the boiling point of water is only 100 degrees C. So heating it up to 500 is overdoing it, 100-200 degrees would be easier and just as effective but slower.

spudthug · Tue Apr 10, 2007 6:15 am

search idiots...except hi hes cool.....

http://www.spudfiles.com/forums/viewtopic.php?t=76&

chaos · Tue Apr 10, 2007 7:08 am

like spudthug said SEARCH!

200psi as said in the linked vids above is about 15 bar(roughly 220psi) so im guessing copper may fail at that pressure and temprature, maybe go wit a diff steel.

ball valve wit heat can be opened wit welding gloves

Blitz · Tue Apr 10, 2007 7:13 am

spudthug wrote:search idiots...except hi hes cool.....

http://www.spudfiles.com/forums/viewtopic.php?t=76&

Well that uncalled for. Why are you calling me an idiot?