SpudFiles

I have unlimited access to schedule 80 pvc.and am building a cannon with a combustion chamber of 8x20 inches and a 3x96 barrel.i'm using a stun gun as a ignition source and metered propane as fuel..has anyone ever attempted a gun this size...

A combustion that size! Wow, how you gonna hold it down? Better yet, how you gonna keep from blowing up the town?

yes, people have. I have seen combustions with 10' long barrels before.

pneumatic wise, they have also been built with up to 20 foot long barrels.

not being a jerk, just answering your question

this will be cool, though.

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It will not be handheld, and will be very unwieldy then.

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very true.

It is going to be stationary..i wasn't planning on holding onto a beast like that..i was just wondering if anyone had ever attempted such a large gun before..i'm thinking of starting out with a bbq lighter with some extra wire at first till i'm sure the thing is safe.....gonna be an interesting project...i'm trying to keep the C.B ratio 1.25 to 1.50...the barrel is gonna be plenty long enough...for oranges and grapefruit..i don't want to build up too much pressure...KABOOM!!!!

...unlimited access to schedule 80 pipe? You could build a *safe* large diameter pneumatic, which is rarely seen anymore, unless it is created from metal.

But I suppose if you are unable to build a piston valve (not saying you can't; don't really know whether you can or not), or do not have access to unlimited schedule 80 PVC fittings (again, I don't know this either), it would be kind of worthless...

Well i got the cannon put together tonight.it has a 8x19 inch chamber with a 3x96 inch barrel...i ended up useing schedule 40 pipe due to the fact that i couldn't get the fittings from work unless i stole them and i'm not about to do that!..and the fittings are a little more expensive than i thought they would be...for 1 cap plug ,1 reducer with another reducer inside that and the female fitting for the cap...now this is just the fittings..$285.00....i about sh###t...one of the fittings was $160.00...so i bought everything in schedule 40 for $140.00...i can get all the pipe i want from work but fittings...no way! unless it's 3 inch or down..i'll post some pics of this thing soon i hope but first i need to get my water pipes thawed out ..woke up this morning to no water in the kitchen...it's below 0 in ohio..[/img]

well I would watch the pressure on the pipe...too much and it will blow up sending plastic into building walls keeping it there forever....


I'm new to this so I'm not sure how much you know but the whole pressure in one of these things just seems like common since to me to watch out...

I cant wait to start on a bigger cannon for myself. I'm in NJ and they may not be legal so I'm keeping it small and will use fuel instead of air.


I do know a friend who has one of these with a 2" barrel and its about 6-8 foot long..he got me started in all this last year lol

revrand65 wrote:Well i got the cannon put together tonight.it has a 8x19 inch chamber with a 3x96 inch barrel...i ended up useing schedule 40 pipe due to the fact that i couldn't get the fittings from work unless i stole them and i'm not about to do that!..and the fittings are a little more expensive than i thought they would be...for 1 cap plug ,1 reducer with another reducer inside that and the female fitting for the cap...now this is just the fittings..$285.00....i about sh###t...one of the fittings was $160.00...so i bought everything in schedule 40 for $140.00...i can get all the pipe i want from work but fittings...no way! unless it's 3 inch or down..i'll post some pics of this thing soon i hope but first i need to get my water pipes thawed out ..woke up this morning to no water in the kitchen...it's below 0 in ohio..[/img]

Haha, sch-80 fittings are really expensive.

especially 8" sch 80 fittings.

using a shorter chamber creates more combustion.
use hydrogen or Acetylene. hydrogen is amazing. only need a little.
hard to get. acetylene easy to get and very effective if you don't mind dying. i don't

Thought you'd be interested in some numbers:

EVBEC 1.5 says that shooting 3" long ice slugs (263 grams) you can expect something like 450-500 fps (muzzle energy of about 2200 ft-lbs), provided you are using metered propane and have a chamber fan.

A lighter projectile (orange, about 130 grams) will give you about 650 fps for an energy of around 1800 ft-lbs.