SpudFiles

I was shooting my golfball cannon yesterday and my piston broke. Luckilly I was holding it bazooka style, on my shoulder, because when I opened the pilot to shoot it, not only did the ball go flying, so did my qev and pilot setup. It went shooting backwards with mad force, at about 75 p s i. as you can see from the picture, the bushing broke into 3 pieces. Thank God noone was behind me or holding the cannon a different way. Always check your cannon before shooting and make sure its safe. This coulda happened to anyone!!
TRY THIS LINK http://imageshack.us/g/88/26249618288521734801605.jpg/

Could you please upload the picture on spudfiles?
Not everybody has a facebook account.

mattyzip77 wrote:This coulda happened to anyone!!

... who did not take the forces of a piston slamming back into the launcher into account.

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jackssmirkingrevenge wrote:

mattyzip77 wrote:This coulda happened to anyone!!

... who did not take the forces of a piston slamming back into the launcher into account.

It had a proper bumper, sponge and half a tennis ball!! Also was working fine the past 200 balls!!!!

I had the same problem with my first QDV. I moved to ABS for the female adapter and increased the bumper thickness.

mattyzip77 wrote: It went shooting backwards with mad force, at about 75 p s i. as you can see from the picture, the bushing broke into 3 pieces.

IMO.... 75 psi isn't a lot of pressure, but it is enough to create forces high enough to eventually fracture plastic construction.

Also was working fine the past 200 balls!!!!

Looks like 201 was the magic number. Everything on this earth fails at some point. Durability of materials is also part of engineering most anything. Plastic can't be expected to have the long life or resilience of aluminum or steel. Glad no one was injured.

Velocity is right... I'm thinking my next will be metal. Looks like my construction isn't as strong as I thought.

Gun Freak wrote:Velocity is right... I'm thinking my next will be metal. Looks like my construction isn't as strong as I thought.

maybe someone should make me a new one, lol, hint hint!!

I just got finished rebuilding it. I was able to attach a new 2 inch slip to thread female bushing, there was just enough room. All I had was a angle grinder with a cutwheel to do the job. I took my time and it came out pretty damn close to perfect. The piston itself was bent too, so I made a new one of those as well. I ran a test with low air pressure, and it sealed and held air perfectly. I know your supposed to wait 24 hours, but I couldnt, I had to know if it worked, and it did!!!! I will post pics soon, gotta find camera!! Once again, I want to thank Gun Freak for his advise!!!! SUPERNA LIVES!!!

New Piston Here
http://imageshack.us/g/26/28731618306355380631605.jpg/

SUPERNA LIVES!!!

YEHH!
New piston... you forgot the washer in front of the rubber washer. Get one as big as you can find that will fit in the seat. This is vital to keeping the piston from blowing out.
Also... gawwwd why did you pressure test it dude of course it will seal but you really need to wait the full 24 hours.

Gun Freak wrote:

SUPERNA LIVES!!!

YEHH!
New piston... you forgot the washer in front of the rubber washer. Get one as big as you can find that will fit in the seat. This is vital to keeping the piston from blowing out.
Also... gawwwd why did you pressure test it dude of course it will seal but you really need to wait the full 24 hours.

I didnt forget, I didnt think it was needed because I used a carriage bolt, blow out from where? The 2 inch steel washer behind the rubber washer seals it perfectly to the barrel port. However, if it makes you happy, I will add one! And dont worry, it was only low p s i, and was sitting in front of a fan for like 8 hours!! I thought it was pretty darn good for my first working piston!! 8) javascript:emoticon('8)')

Nice QUADRUPLE post Mr Cool 8)
It is needed. You're gonna have to unthread everything to put it on but it is the only way your piston will work correctly.

mattyzip77 wrote: it was only low p s i, and was sitting in front of a fan for like 8 hours!! I thought it was pretty darn good for my first working piston!! 8) javascript:emoticon('8)')

Don't be surprised if this piston housing also blows to bits. You could have got bubbles between the glued joints from when you pressurized it. Then again, the joint may be fine. Who knows.

Would I use it personally, no.

I realise this post will do little to change your mind but hopefully you'll refrain from ignoring instructions in the future. You're supposed to wait 24 hours for a reason.

Nice Desktop background matty! I recognize that image. Definitely use the washer. It has nothing to do with sealing but it will keep your sealing face from getting blown out with the ammo you are shooting. I've had two do that now and have since added the extra washer.