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Safety of HDPE Golf Ball Cannon


bjc4073

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I made a howitzer looking cannon out of 1.91 mortar tube. It takes about a dixie cup and a half of homemade bp and a golf ball wrapped in paper towel. I eventually blew the plug out (which was only stapled) at about 2.5 cups of powder. At all times I was behind a windshield at a safe distance. So is it safe?

 

 

BTW the plug blows at 0.55 and the barrel moving was my fault. The dowel that I brought broke on the first shot so I resorted to twigs.

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Why do you allow so much backlash in the barrel hinge? It seems like its robbing your shot.

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Firstly "an unknown person on the internet" isn't the best when asking about your safety!

 

secondly you've pointed out some failings which need designing out before you do further tests.

 

Remember that BP imparts heat to the barrel when it fires, the barrel will warm and will start to perform differently when it gets too hot.

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Why do you allow so much backlash in the barrel hinge? It seems like its robbing your shot.

I only brought one dowel which broke. I was using some twigs but I have since bought some metal rods. No doubt it was taking some power out.

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  • 3 weeks later...

Nice video. I would also say that you may have too much powder in there. Not that the tube is in terrible danger at the pressures you are doing, it's just a waste of powder with all that fire after the shot. And that extra fire is extra heat. Hdpe will just split and deform if you go to far with it. try it with 1.25 cup and pack in over the golfball with some bread about 2". Other than that, nice job on putting it together.

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Dam i only use 4oz. and that will shoot a 2lb. lead ball 1000yds. Spaarx you are giving bad advice, i have heard of people putting a wet paper towel in them and busting the barrel. there is no need putting anything in front or that ball. Both of you need to go here and read.

http://www.go2gbo.com/forums/blackpowder-mortar-and-cannon-sponsored-by-seacoast-artillery/

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I did say he was using too much. But your right about the packing thing. I was considering how lightweight golf balls are compared to a 2 pound lead ball. I have loaded powder in excess of that back in the day with small hdpe golf ball cannons to find the point of fail and never did until it was packed to the muzzle with 2 Oz.

 

But yah forget the whole thing about packing anything in there. No need to be wild and crazy like me doing dumb stuff like that. Dynomike knows his stuff about cannons.

Edited by Sparx88
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Maybe this will help. Just trying to keep everyone safe.

http://gunneyg.info/images/SwitlikLoadsOne.jpg

Edited by dynomike1
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  • 3 months later...

I made a howitzer looking cannon out of 1.91 mortar tube. It takes about a dixie cup and a half of homemade bp and a golf ball wrapped in paper towel. I eventually blew the plug out (which was only stapled) at about 2.5 cups of powder. At all times I was behind a windshield at a safe distance. So is it safe?

 

 

BTW the plug blows at 0.55 and the barrel moving was my fault. The dowel that I brought broke on the first shot so I resorted to twigs.

Awesome

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  • 2 weeks later...

ruff numbers for you to make your own call-
using a moded version on this spread sheet http://closefocusresearch.com/calculating-barrel-pressure-and-projectile-velocity-gun-systems

golf ball rounded up to 46 grams

1 gram of sporting bp creats 270cm3 of gas

usable barrel of 10.5" asumeing "standard" 12" firework mortar with 1.5" plug is 491.75CM3

a 5 gram charge would fill the barrel volume to 27 psi giving 120 fps on the golfball , should give you plenty of range,some were better then 600', likely a good bit better at a 25-30 angle

dissection of a "sky tiger" 1.75" ball shell was overall weight of the shell [casing, fuse, etc] was 63 grams. lift charge 6 grams

DR11 HDPE is rated to 160psi

powder burn speed and comp will effect the PSI, this is effected by the quality, grain size and confinement (such as a sub call powder chamber on a BP mortar)




Edited by AAF
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  • 1 month later...

Thats pretty impressive.

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How far does the ball go, if you shoot the thing straight up, Mike?

 

Good powder should result in HUGE flights with just a few grams of powder. A standard US baseball (about 150 grams) will go 300 feet high off about 15 grams of decent powder, with 1/8" clearance between the mortar and the ball.

 

LLoyd

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  • 3 weeks later...

My guess would be 2000-3000yds.

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  • 5 months later...

Never been here before :mellow: Last week I made a nice little cannon from a 3" HDPE tube just for fun. But what is the talk about a dixie cup of powder? I find 25 grams of MCRH to be sufficient for launching baseballs! A dixie cup in a 1.91? I had a friend to show up one day with a cannon he had purchased in an antique store. It was pieced together with industrial valve wheels but the barrel appeared to be machined. It too was approx 1.9 bore and appeared sound- but I have heard of a couple people pushing homemade cannons to far and getting killed by shrapnel. 15 g BP in his cannon sent a golf ball out of sight-somewhere in the pastures. Since there is really no way of knowing the strength of metal barrels aquired from parts unknown I elected to make my cannon simply a horizontal version of a hdpe mortar. I bought the nice little wheels on amazon and the only other things were a couple 1/2 bolts and U-clamps and couple cans of spray paint. Everything else is wood. 2x4 shaped for the barrel platform and used 4x4 and 2x4 for breech blocks (to prevent the plug blowing out). I looked around for real cannons but I not wealthy. Mine cost about $30.

It is just as safe -more so- no flowerpots as a typical fireworks mortar. But really, how much powder is a dixie cup?

Edited by Merlin
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Merlin,

Most golf ball guns typically use 3g-9g of BP (depending upon the type and method of manufacture of the powder).

 

We USED to use 9g all the time, but amateur powders have gotten better...

 

Lloyd

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Hey Lloyd good to hear from you. Seems like a lull on the forum. Yeah 9 grams seems reasonable. One of the posts here a guy claims to use a Dixie cup and more. A 3 oz Dixie will hold around 50 grams of mcrh. That means he was using 10 times more powder than he should. Maybe I missed something.

Correction in the first post he says 2.5 Dixie cups so he must have been using really weak BP!

I test my powder with 25 grams in a 3 inch with a baseball for altitude. Way more than required for a 3inch ball shell! I only use 35 for a four inch and they are high to avoid fallout.

Edited by Merlin
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Dam i only use 4oz. and that will shoot a 2lb. lead ball 1000yds. Spaarx you are giving bad advice, i have heard of people putting a wet paper towel in them and busting the barrel. there is no need putting anything in front or that ball. Both of you need to go here and read.

http://www.go2gbo.com/forums/blackpowder-mortar-and-cannon-sponsored-by-seacoast-artillery/

Your right. I knew of a couple deaths from overloading homade cannon but that liist is staggering. Seems home made metal cannons cause more death and injury than all of pyrotechics. Wonder they haven't been outlawed.
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  • 2 months later...

Merlin; you don't have to be so up tight about the cannon thing. You could fall out of bed and break a neck too. I think there are enough things outlawed now. Better to start teaching about common sense instead of relying on forums and U tube , and the like. Everyone now days seems to think that someone else is responsible for them.That sucks.

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I did say he was using too much. But your right about the packing thing. I was considering how lightweight golf balls are compared to a 2 pound lead ball. I have loaded powder in excess of that back in the day with small hdpe golf ball cannons to find the point of fail and never did until it was packed to the muzzle with 2 Oz.

 

But yah forget the whole thing about packing anything in there. No need to be wild and crazy like me doing dumb stuff like that. Dynomike knows his stuff about cannons.

Merlin

Posted 10 September 2016 - 10:33 PM

dynomike1, on 28 Aug 2015 - 06:59 AM, said:snapback.png

Dam i only use 4oz. and that will shoot a 2lb. lead ball 1000yds. Spaarx you are giving bad advice, i have heard of people putting a wet paper towel in them and busting the barrel. there is no need putting anything in front or that ball. Both of you need to go here and read.

http://www.go2gbo.co...oast-artillery/

Your right. I knew of a couple deaths from overloading homade cannon but that liist is staggering. Seems home made metal cannons cause more death and injury than all of pyrotechics. Wonder they haven't been outlawed.

 

 

 

 

Yes, and that was said quite awhile ago now and I admitted fault and changed that. It was bad advice. I don't have any bad reputations or history of injury, death, damage, or the like associated with cannons or pyrotechnics. Call me lucky, careful or whatever. I would like to see that list of home made cannon mishaps. Beings most cannons being used or produced at the sizes talked about here, small cannons, for blanks are made in someones home or garage/"shop" and sold with a disclaimer. Homemade is not a bad word as a lot of things we buy and use today started there. Anybody reading this understand that I'm not minimizing research and safety, they are number 1, then you can move forward. But don't get discouraged when someone wants to depress your interests with fear or statistics because those numbers are created by the one's you don't want advice from anyway. Merlin, dynomike and a few others know what the deal is and give sound advice and I would trust them with my life as I already have taking advice from them and others concerning pyro and cannon use and creation. :)

Edited by Sparx88
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  • 2 months later...

Jesus, I just cronographed my 20 HV cannon at 1345fps pushing an 800 grain custom spiral lead pill with 250gns my BP. I wanted genuine high velocity. And did it. The breach is triple sleeved, penetrant crack tested for the1st 6 shots, proof tested at double charge by a qualified gunsmith. And it shreads the piss out of anything forward of the muzzle!!! Gunna range test a few @ 200m today and see if these spiral pill will grip the smoothbore. Should, as their just undersize, expansion due to pressure and heat should expand them just enough

Shame the crony won't work again....

Edited by Redrocketman
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