My Big Bang pop guns

[BowerR64]

My friend has a big bang cannon when i checked it out it was so simple i figured i could make something like that with PVC. His is one of the smallest ones you can buy but it sure does pop pretty loud.

I like mine better. I built one for him though



These are made from 1" PVC, 2 1" PVC caps, 6" PVC for the barrel down to 3/4" PVC 6" long. 1" PVC Tee all SCH40.
The ignighter i got from walmart king grill ignighter $1.

Everything else i found around the house, the grips are from a shelf from a harbor tools aluminum gun case. The sights are from a toy gun (top) and the bottom are a shotgun fiber optics kits from walmart i used one of them for my AR15-22.

Click here for the forum rules read them.

[jackssmirkingrevenge]

Neat, I really like the way you incorporated the the ignitor into the design to form a trigger guard, nice work!

[BowerR64]

I almost didnt add the trigger guard but i thought ide try and it worked out ok. A little sloppy with the hot glue but i figure if i paint it you wont see the glue. Then i decided white might not get me shot so ill leave the color safe

better view of the trigger guards before i cleaned off all the ink and put on the sights.

[PeteS]

Very nice. I really like the look of them and I bet they are a lot of fun.

[BowerR64]

We shot them all day today at my friends watching the superbowl, we were shooting carrots, marshmellows, wads of papertowels, we even stuffed a clean female product down the front.

Ill tell ya for how much carbide we use they have some amazing power. Ide bet if i weighed the amount it would be around 1-2 grains if that.

I made a few changes to them though. When i shot a marshmellow from them at my home the rear cap blew off wich im lucky i wasnt holding it up near my face it might of gave me a fat lip. I added a screw to both caps and cut out a little notch to push in, twist and lock so the caps can both be removed but locked on under the pressure.

I built 2 larger cannons using 4" to 3" SCH40 but im not going to risk putting anything down the barrel. This gas seems to burn WAY to fast to be safe.

[BowerR64]

I made a couple more from the parts i had left. Couple friends wanted one after the superbowl party.

[jrrdw]

Nice collection your building there...

[jackssmirkingrevenge]

Have you thought of letting syringe fueling into your life? Definitely more safe and predictable than your current choice of fuel.

[BowerR64]

Is there any starting links to it? I have about 7 tubes of fluid that came with the grill ignighters i used for the pistols. I tried a smaller one adding a little nipple that came with the ignighter and then tried to fill it but i couldnt get any detonation so i guess im unsure how it works or needs to be mixed.

The powdered carbide seems very simple to me. It also seems fool proof, the scoops ive fixed into the back caps hold the right amount of carbide so that when they finish the reaction with the water there is the correct amount of pop. If you try to detonate the charge to early its a dud and if you try and over fill the carbide it doesnt even go off till the rear cap is removed to allow more air.

I kinda like the bang they give off as well. They dont have to be used to shoot a projectile. I built them for noise but a marsmellow is light enough and fits loose enough not to create to much pressure.

The smallest one sounds about like a 380 and the larger ones sound more like a 45 cal going off. Those with the 1" muzzle have a deeper sound then those with the 3/4" muzzle they have a higher pitch crack lik ea 9mm maybe.

I have 2 larger built cannons using 4" Tees down to a 3" reducer they take about 25-30 grains of carbide and sound more like a 223 or a 308 i have not tried to shoot anything from it but on another forum ive read about using a slightly over sized tennis ball works.

[jackssmirkingrevenge]

tutorial here: http://www.spudfiles.com/how-to-databas ... 22301.html

[BowerR64]

The thing is with the powder it isnt pure acetylene nor is it pure oxygen like found in tanks. Ive just taken the old big bang cannon idea and put them in a pistol form and removed the old style spark ignighter that used flint. The amount of air and powder are still about the same.

Those little big bang cannons are made of cheap pot metal.

[Technician1002]

Caution on using PVC for Carbide Cannons. PVC is brittle and will eventually shatter. Calcium Carbide mixed with water does produce Accytelene. Accytelene has a very wide explosive range and does detonate when mixed properly. This detonation is what produces the loud sharp bang that is so attractive. Unfortunately the repeated shock to PVC will cause it to fail.

[BowerR64]

Yeah thats why im not really thrilled about shooting anything out of it. The little guns we have only shot marshmellows out of it, they arnt a tight fit and they have little to no weight.

I guess i shouldnt be here because mine isnt really a "spud gun"

The first one i built i just put the caps on with my hands, hand tight and it took 2-3 shots before it blew the caps off.

Im working on a Rifle now to shoot the mini marsmellows also. The smallest marshmellows they make 1/2" i thin they are.

[BowerR64]

Caution on using PVC for Carbide Cannons. PVC is brittle and will eventually shatter. Calcium Carbide mixed with water does produce Accytelene. Accytelene has a very wide explosive range and does detonate when mixed properly. This detonation is what produces the loud sharp bang that is so attractive. Unfortunately the repeated shock to PVC will cause it to fail.

Maybe you think the caps are threaded?

Ive put 2 safty spots on all of these smaller guns, i put a small allen screw in both caps and i put a key cut in both connections to the tee.

These 2 spots are both pretty weak i could break them off with my fingers. They will let go and blow the caps off before the PVC lets go.

I could test them with a scale using a dowel rod and pushing down on the scale till they break off. We almost have a setup to figure the velocity of the marshmellow. We tried with just the marshmellow but i think we will need to wrap it with foil or something solid to trigger the sensors.

[jackssmirkingrevenge]

Neat little armory! To be honest I would still go with a quick calculated syringe squirt of propane to give more consistent results while still having a decent bang, but you seem to have the carbide thing figured out it could be that your ignition would have to be modified to work with butane or propane.

Any chance of a video of these things in action?