This is what happens when your piston is too heavy!!!
Posted: Tue Apr 19, 2011 10:52 am
by hyperspaz
So here's a video of my golf ball cannon firing at 100 psi with a solid epoxy piston:
[youtube][/youtube]
Posted: Tue Apr 19, 2011 10:58 am
by jackssmirkingrevenge
Clucking bell!
What were you using as a bumper, and what was the piston travel?
A solid piston that big is a bad idea, there's plenty of advice inmy how-to on making lighter built-up pistons.
Posted: Tue Apr 19, 2011 11:01 am
by hyperspaz
Bumper was a tennis ball and the piston travel was just under an inch.
Any ideas on how I can fix it? Is there any pipe that fits perfectly around a 2" coupler?
Posted: Tue Apr 19, 2011 11:14 am
by warhead052
Holy crap.... OW! Did you get hit by it?
Posted: Tue Apr 19, 2011 12:20 pm
by Technician1002
I had that happen once with my ABS cannon. The female breech was PVC. It shattered and the piston hit my foot. I was wearing heavy leather shoes at the time. I replaced the PVC with higher impact resistant ABS and made my bumper 4 X as long. Since then, I've used lighter pistons, shorter strokes, non brittle parts (except the original Marshmallow cannon which did finally break the cap) and longer bumpers.
Edit, Made you an avatar photo..
Marshmallow Cannon with broken pipe cap. It is now replaced with Iron.
Only fair to show the fix.
Posted: Tue Apr 19, 2011 3:13 pm
by SpudBlaster15
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Posted: Tue Apr 19, 2011 5:45 pm
by Insomniac
Ah, I hadn't thought of that before SpudBlaster... You have a good point.
Posted: Tue Apr 19, 2011 6:27 pm
by Gun Freak
Thank god you were remote firing it...
Posted: Tue Apr 19, 2011 6:32 pm
by mark.f
Who was the guy saying "It broke..."? He earns my Captain Obvious award for the whole year.
Posted: Wed Apr 20, 2011 12:14 am
by jackssmirkingrevenge
mark.f wrote:Who was the guy saying "It broke..."? He earns my Captain Obvious award for the whole year.
Perhaps he was harbouring the misapprehension that it operated on the "countershot" recoilless rifle principle, and that was meant to happen...
Posted: Sun Apr 24, 2011 6:03 am
by shiny455
you may have inspired me to test stuff with a string for the first time
Posted: Sun Apr 24, 2011 7:10 am
by jrrdw
[youtube][/youtube]
You earned it.
Posted: Sun Apr 24, 2011 8:10 am
by Technician1002
Absolutely amazing. A cannonball that can take 90 degree bends at velocity.
On a more serious note, a mod promoting a prohibited magic powder launcher? Will the shame never end??
Posted: Sun Apr 24, 2011 8:18 am
by jrrdw
Gotta love Wile E. Given my self this one over and over through out life...
So hyperspaz, rebuild plans?
Posted: Mon Apr 25, 2011 2:13 pm
by hyperspaz
Well, I'm not quite sure how i am going to rebuild this one.
It broke once before at the threaded female piece from over-tightening. You can see where I added a coupler and rebuilt the top part. but now if i try to do that again, there will only be an inch for the coupler to grasp, so I'm worried that it wont make a strong enough bond. I guess my best bet would be an inside pipe splicer like this: http://flexpvc.com/cart/agora.cgi?produ ... InsidePipe . then i could rebuild the top.
