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Could you make a ghetto mortar out of an iron pipe?

Imagine that you take a four foot long iron pipe and cap one end of it. Near the capped end, you make reasonably sized exhaust holes. Just above said exhaust holes, there would be a few metallic protrusions that would stop a round from sinking to the bottom of the barrel. Aforementioned round shells would be made of smaller, thinner metal and filled with propellants. Means of ignition is still TBA. But if such barrel and rounds were constructed, could it effectively launch rounds long distances?

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Tombini8 years ago
Yes, although I wouldn't recommend using any metal (try PVC or paper based tube) Depends on the type of the propellant, the projectile etc
Mr. Deeds (author)  Tombini8 years ago
Well wouldn't the propellant, if hot enough, burn through PVC pipe. Beside that point, though. Everything in this idea is perfectly plausible and would work if I happened to build it. As far as other questions, I have to wonder what propellant would be advisable?
Firstly PVC does work for low pressure cannons (I have used it myself) because the energy released from the reaction (although it is very exothemic) only lasts for a small period of time, this means the tube won't get as hot as many people think. Secondly black powder is the perfect propellant, use somthing that is a low explosive (deflagrates rather than detonates) You could use flash candy (see my instructable), but only as a last resort
Mr. Deeds (author)  Tombini8 years ago
Hmm.... never knew that. I have to tell you that I'm a severe amateur at pyrotechnics. I really don't even know some of the simplest things being that I'm only fifteen and am far too impatient to do any thorough research. So I really appreciate all your help and patience. I will use black powder and PVC as you suggested, but now I'm wondering as to the shell. Could the shell possibly also be made out of PVC that fits snugly into the chamber, or would one want a slightly more loose-fitting variety? I also have questions as how this would be constructed. My idea is to take another, smaller piece of PVC and cap both ends. In one cap, a hole would be drilled into which a simple fuse would be inserted. A seal of some sort (I'm thinking something suck as tack or clay) would be placed around the fuse on the inside of the round to prevent powder spilling out. When a round would be ready for launch, one would light aforementioned fuse and drop the round into the barrel. Because of the slits in the barrel mentioned in my original post, proper air supply would be available for the fuse to burn down and ignite the powder. The major concern here is as to whether the hole would be big enough so the shell wouldn't just explode. If this wouldn't work, I was thinking that several holes could be drilled in the fuse end of the shell. A piece of material such as cloth or paper would be placed on the inside of the round, over the holes. A hole would obviously go through this material for the fuse and the wax would also go over it. Then when the powder would ignite, it would burn through that material and provide more escapes for exhaust. I apologize for the many questions I have. It's just that I want this to go off smoothly if I ever do it and I wouldn't want plastic fragments lodged in my skin. Thank you for all your time.
I'm almost 16 You're shell idea seems valid although I would test it a few times without a shell then with a shell full of sand before you get into the real deal. Instead of using a fuse that requires oxygen just use a sparkler, they are common and easy to obtain. I'm a bit confused about what you're trying to say about you're design... Easiest method; -PVC tube with end cap on one end -Drill a hole in the end cap to be able to insert fuse -Place required amount of propellant in aluminium foil -Put aluminium foil down the tube with the fuse pushed into the foil so it is contacting the propellant -Put projectile into place -Use This is a very simple and rough design but perfect to get your head around some of the concepts Use a tightly fitting projectile as this minimises wasted energy from leaks therefore maximising energy transferrance and distance Safety is a key factor in participating in ANY activity that involves explosives, so if you havn't allready got one consider buying a full face shield, my father works in the country alot and gives me safety gear all the time (I have 4 safety glasses, 2 full face shields and 3 pairs of Dexi Pro gloves)
Mr. Deeds (author)  Tombini8 years ago
Really? Good to know there's other young instructable users out there. I think you've perhaps got my concept a little off. The PVC capped on both ends, mentioned in previous posts, would actually be the projectile flying out of the barrel. The entire round would be something of a rocket. If it would be helpful, I could try and whip up a paint sketch of the multiple-exhaust-holes ideas. The general idea is that the completed round would have multiple exhaust holes covered by cloth. So the layering (from the bottom of the shell) goes PVC end cap (with fuse and additional exhaust holes), a relatively thin piece of cloth preventing the propellant from leaking out the holes, and finally the propellant itself. So when the propellant does ignite, it burns away the cloth and there are more holes for the exhaust to travel through. This (hopefully) would create more... thrust?
I think we have similar ideas... I have been looking to expand my rocket launcher and make it actualy fire the rocket out using some propellant, this would allow a small increase in exit velocity and would contribute to some decent recoil! I need to ask, what exactly do you want to do with the shell? Do you want it to explode? Be a rocket? Create smoke? I think you should just experiment with inert projectiles to get a general diagnostic of the design. Then once you feel you are adequately prepared, start using rockets and other projectiles.
Mr. Deeds (author)  Tombini8 years ago
Just had to make sure we were on the same page. So you do like my idea, though? I'm honored. As to what the question of what I'd want to do with the shell, I rather like the smoke idea. Explosions in my neighborhood would not be particularly appreciated. I would think that after you load the black powder into the shell, you could place a think piece of cardboard over it and proceed to pour smoke bomb mixture in. This might, however, melt the shell given how hot the mixutre burns. So if you want reusable shells, I might not advise smoke mixture.
Ahhh, smoke bombs That brings me back to when I sold little ones at school for a $ each (good times) anyway... don't use a casing just use a slug, a while ago when I was tampering with roman candles I made a cannon; It was made of aluminium with an ID of 25mm and a length of 1500mm (yes a meter and a half!) The projectile was a 60 gram lump of Rcandy and the propellant was 10 grams of flash candy. The projectile reached an apogee of around 300meters and because only half of it burned I heard the other side thud into the ground. Trust me it will work.
Mr. Deeds (author)  Tombini8 years ago
This is what I gather that you said through my highly scientifically illiterate brain: You had a pipe with a diameter of 25 mm and a length of 1500 mm. You launched a 60 gram blob of moldable smoke mixutre out of that pipe with 10 grams of propellant. This blob reached a maximum hight of 300 meters and landed with a satisfying thump into the ground nearby. I would really like to try this, but would need rather detailed instructions as to not lose any of my precious phalanges and/or other body parts. Also... what's wrong with a casing? It seems like a rather neat idea to me. Is it impractical or implausible in any way? And if I did happen to load it up with quite a bit of black powder, would it happen to melt the shell? If at all possible, I would like to reuse the casings and just load them up with more powder to easily fire more rounds and only have to have a supply of black powder handy. Let me know on your thoughts. By the way, do you happen to live in the UK?
No, I live in Australia and Ive never used black powder.
Our government restricts alot of chemicals -sigh-
I'm not trying to dissuade you from using a casing I'm just trying to point out that it is much easier to work from the ground up, write down the plans you have now and slowly progress onto them.
With the casing, if the black powder takes more than a few seconds to burn out then it will probably melt the PVC. Thats one reason why not to use a casing
The amount of propellant I used looks like this (when confined)
http://www.youtube.com/watch?v=GNzbGgi8WvU
At 25-26 seconds (just after the rocket motor)
Also, give me you're youtube account (if you have one)
Mr. Deeds (author) 8 years ago
On that note, though, do you have a facebook? Look up 'Nick Naumann' if you do. It's the one with the pic of the redhead kid.