Carbide cannons...

[Victor3]

 With the recent posts about football and boy scout cannons, I'm wondering if anyone's ever built a large carbide cannon?

 Might be more readily accepted by decision makers when salute cannons are proposed for an event. No evil gunpowder to scare the hand-wringers, and every guy had a Big Bang cannon when they were a boy, right?

[cannonmn]

Answer is yes.  The large scale carbide cannons are called propane cannons.  The smaller ones are used for bird scaring in farm fields, cost about @250-350 depending on features.

Much larger ones were built by FMC corp. in 1960's for tank gunfire simulation.  I have one, tube is about 8 feet long, hangs under main gun tube.  It has a small oxygen cylinder and a propane tank in a scuba-backpack-like carrier, then there's a little bottle of an evil chemical that makes the smoke for each shot.  The electronics box has a timer that fires about five rds. a min. or whatever tank max rate is, but also has single-shot button.  The mechanics include solonoid-gas valves to meter the gas into the gun.  The noise from that beast is thunderous, sort of close to the tank gun, with a big ball of flame maybe 6 ft. in diameter in daylight.

These are easy to build and quite safe as the propane-o2 mix will not bother even fairly thin steel or aluminum.  The only real hazard is the noise which can cause hearing damage.  My ears ring constantly partly due to this thing.

Many owners of original de-milled WWI and WWII cannons adapt them to fire oxy-propane, and they are pretty much always satisfied with the noise it makes.

[nematode]

I'm not a cannon knowledgable person at all but can confirm what cannonm posted with an emphatic "yes".
If you visit www.youtube.com and enter carbide cannon in the search window you get a bunch of hits and see some decent size carbide cannons. Some of them appear to be made from pvc pipe.

[Cat Whisperer]

OK, carbide and propane are a bit out of the normal topics we entertain here.

Great fun, and we all have some hair raising stories to tell of them.

Each has it's own safety issues - I can tell some ear shattering stories; but

this is OFF TOPIC for this board, albeit great fun.

Enough said.  Thanks for your understanding.

[Cat Whisperer]

Unlocked.

My memory failed me.  So much for trusting it.

Appologies to all.

Bring it on.  (Safely).

[Double D]

Actually, I am older than Tim and have a much better memory, come to my house and will tell you tales all day long about the good old days...

Carbide cannons have always been on topic on this forum.  What Tim is vaguely remembering is a discussion about the inappropriate use of agricultural propane cannons several years ago.  We put that discussion of limits.  The Discussion of signal guns is allowed here also.  So by extension Signals guns of propane or made from artillery simulators to replicate pre 1899 Artillery are allowed.  Post 1898 devices would also be apppropiate as long as they were discussed in some releationship to Pre 1899.

[Cat Whisperer]

While I don't have any pictures, I DID try propane in my 16" mortar to see if I could get it to launch the 15" beachball.  Couldn't get the mix right though.   

[Victor3]

 Thanks for unlocking it CW

 Seems to me that a carbide cannon would be a good choice for a safe noise maker where BP (or tanks full or gas) might be frowned upon. Heck, it's even got water in it. What could be safer?  Might even be useful to blow out some confetti.

 I was hoping someone might have made or used a nice safe carbide cannon. I've seen the sewer pipe ones on YouTube. Although they might be safe, I'd like to see something in steel. I've thought about maybe making one to look like a naval cannon out of some stainless tubing I've got. They're a dead simple design compared to something with tanks, solenoids, batteries, etc.

 I think even a fairly thin-walled steel one would be okay. In my experience with Big Bang cannons, the gas mixture appears to be self-limiting as far as how much boom is produced. Not enough acetylene and it doesn't ignite, too much and all you get is a smokey 'cough' out of the muzzle.

 Question is, how to make an effective steel one. Anybody ever seen plans? I suppose one could copy the internal dimensions from one of the plastic designs.

[Cat Whisperer]

The Army uses many different models of propane powered "simulators".

Designs should be able to be gleaned from the patents.

SAFETY - hearing is going to be one of the BIG concerns as these things WILL make your ears bleed.     
   

[Cannoneer]

Victor,

I know this doesn't meet the criteria for large, but I thought you might find it interesting. It was on ebay a few years ago, and its only 10-inches long, but it caught my attention because the machinist evidently spent some time fashioning the thing. There were a bunch of pics, but this is the only one I saved; the ignition system was a small spark plug hooked up to a battery, and it also had some kind of automatic feed thingage attachment that fed the right dose of carbide powder into the water chamber. At the time, it kind of intrigued me, that someone would put this kind of effort into making a one of a kind carbide cannon.

[Victor3]

 Thanks Boom J.

 Wonder why it was made flattened like that? Do you remember if there was a water reservoir on the bottom?

 I was thinking to use a modified piezoelectric BBQ ignitor to light the thing off. Maybe with just a simple capped fitting on top to dump the calcium carbide in.

[Cannoneer]

Victor, its not flattened, the barrel is round, but I enlarged the pic to the max on my photo hosting site, and sometimes the images get distorted. The water reservoir was in the wide rear part of the barrel, and the line you can see there was where it could be unscrewed apart, (I guess to clean it out, if needed) and the spark plug screwed into that part coming out of the breech.

[Victor3]

 Okay. I thought it might just have been a fig newton of my imagination, but it did look kinda squashed.

 I think I'll cobble up something simple out of material on-hand and see what happens...