DWV PVC PIPE

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
queensland spudder
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Sat Aug 08, 2009 1:34 am

Hi, im a new member on this forum however not new to potato guns either.

Im going to build a cannon made from DWV PVC fittings and pipe. The cannon is going to be powered by normal deoderant with a spark ignition system.

The combustion chamber has a "T' shaped fitting with two screw ends and the other end is used for fitting adapters ect. I measured the 'T" sections in two parts to simulate the combustion chamber was one long piece of pipe . Its Aprox 290mm.

since the 'T' section is not the right size camber i want ,im going to add and extra 290 piece of 100mm DWV PVC PIPE with a enlarged part to fit the 100 to 60mm reducer

The Cannons dimension are shown. Chamber (100mm dia 580mm aprox in lenght)

Barrel (60mm in da and 2.210 meters)
I ran a C:B sim on Burnt Latkes site, The C:B was 0.7:1 probably less due to the weirdly shaped adapter maybe 0.69 dont know for sure.

Im just wondering wether a DWV PVC Combustion camber of that size will be safe to shoot. BTW im not using any fans or fuel injection valves just screw open the lid spray ,then it screw back on ,then fire technique.
queensland spudder
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Sat Aug 08, 2009 1:50 am

Also is feasible to make a iron sight of a cannon, i made one previously on my 50mm cannon (that one was a beauty) i couldn't get it to work cause it was hard to aim the gun cause it didn't have a stock to press against yer shoulder.

Has anyone tried to make iron sights for a cannon and has succeeded in aiming the bloody thing and got good results?
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jackssmirkingrevenge
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Sat Aug 08, 2009 2:31 am

For a "spray and pray" cannon, DWV is generally safe to use provided you never use a projectile that is too tight or too heavy to jam in your barrel and create and overpressure, remember that nature always goes for the path of least resistance.

As to iron sights, I had made an adjustable set forthis projectthat worked pretty well.

The adjustable element (windage only) looked something like this:

Image

Still, if you have a look on eBay, you can get a reflex sight very cheaply that would be effective for a smoothbore potato cannon (hey, it works for shotguns :D) and infinitely cooler than iron sights ;)

Small note on forum etiquette, if you have more to say try and edit your previous post instead of double posting ;)
queensland spudder
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Sat Aug 08, 2009 2:47 am

sweet thanks for that advice.

About jamming stuff into cannons , would it be OK if i were to use a 50mm silican tube (with nozzle) to shoot out of a cannon . Should i mention that the the tube wont be full it will be most likely half full or least a quater.

My next question is , do i have to have a E class firearm license to fire a cannon out of city limits in the forest or in a field.

My last question is what you compare a spud gun "kick" to a real firearm.
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Crna Legija
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Sat Aug 08, 2009 3:09 am

The kick of a combution is lost bigger than a 22. But it depends if you have heavy ammo. If the silicon tube is full it should kick something like a 22 250/306 still not that bad. you should be able to handle it
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jackssmirkingrevenge
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Sat Aug 08, 2009 3:47 am

queensland spudder wrote:About jamming stuff into cannons , would it be OK if i were to use a 50mm silican tube (with nozzle) to shoot out of a cannon . Should i mention that the the tube wont be full it will be most likely half full or least a quater.
You should be fine as long as it can slide freely in the barrel
My next question is , do i have to have a E class firearm license to fire a cannon out of city limits in the forest or in a field.
It is my understanding that spudguns are specifically banned under Aussie law (I'm assuming that's where you're from) and cannot be licensed, so do your best to stay away from "witnesses" if on public land and try and be as discreet as possible.
My last question is what you compare a spud gun "kick" to a real firearm.
It depends on the spudgun and how heavy your ammunition is, with my larger combustion projects firing heavy ammunition the felt recoil is comparable to a 12 gauge shotgun.
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