If you live in a country where spud guns are illegal, OR classified as firearms read the following:

DO NOT EVER, EVER USE YOUR SPUDGUN ANYWHERE BUT ON YOURS OR A MATES PROPERTY.

I know many of you reading this are probably rolling your eyes, and Im sure at least one of you use your spudgun in ...

Well, to get things started, After building my first pneumatic (over/under, ball valve, like a 20:1 chamber barrel ratio) out of PVC, I was so damn excited to use it, I only left the glue to dry for 20 minutes. It felt hard on the outside, so I supposed it was ready. I attached the pump and got the ...

Ok, I'll clear that up.... this is really for troubleshooting, but a few stories on failures would liven this up a bit. So dead clear, ANYTHING THAT HAS GONE WRONG WITH YOUR LAUNCHER, OR ANY INJURIES/ DAMAGES THAT OCCURRED, POST IT HERE, even if you fixed it... tell us about it so others can learn.

Umm, I dunno why you would actually bother with a motor, for several reasons;
1- To turn a blow valve you need a bit of power unless you have a really well lubed one
2- A powerful motor would be fairly large, 4 cubic inches or so, where would you mount this?
3- A motor costs a lot more money than a ...

This post is for all those people who have spent a S**tload of money, made a pneumatic, only to have something stupid (like a piston) fail or leak.

If you have general solutions to common problems, other people's problems, or would like to post your launcher's failure, feel free to do so. Try to ...

That's pretty nice.. I gotta go to the hardware tommorow anyway to get 2 threaded sections (for piston servicing >>>$27<<<!!!!!!!) so I might as well pick up some wood and O-rings... Ill go google check valves now... seems useful for use in a piston

Hmm, any ideas on what to use... I need something that will fit into the chamber nicely, and be easily made from household objects... would rubber off the sole of a shoe work... I'm all out of other stuff to use. Any other rubber I have available is either too hard (like rock hard) or too porous ...

Should any of you be interested in this design ( no problems with it as far as I can tell) I have this for you all to feast you eyes on... just a little something I made in GMAX ( a 3d rendering application... should any of you have GMAX and want this model and/or a spudgun construction set I have ...

Damn.... well thanks for your help all... I might try a small fill chamber with a ball valve to get that piston slammed against that barrel.... [/img]

OK, shortly after building my piston gun... I realized the piston was very bad, and was causing major issues with the rest of the gun.

So far:
-The bumpers have come off, and got lodged INSIDE the sprinkler valve, almost launching out the other end...
-The piston randomly decides whether to seal ...

Ummm, It doesn't have an equalization hole... but the piston is so damn ghetto air gets around it anyway... A BIG problem seems to be that our bike pump ain't filling the area behind the piston fast enough to actually push it firmly onto the barrel.... and is foam (cut from a camping mattress ...

Sorry mate, but it's hard to figure out what the problem actually is, from your description (Try to post pics... would be very helpful). If you have cast it out of epoxy, why not make the piston a little longer? And I suppose you could push the barrel in a little further, but that would decrease ...

It depends on the pressure... (one way it wont hold as much as the other way) This is because of the way the blowgun is built. Usually, the trigger should be opening up away from the valve (the pivot is closer to the sprinkler valve than the release mechanism).
If you have a weird blowgun... and it ...

I built the cannon around this.... but it sure as hell ain't the 'small smg' I was going for... in fact, this launcher is as big, or bigger than the previous one.
Skhrnykhsk should be posting pics soon...
At the moment, it's not working too well (if at all).

Sometimes the thing works perfectly ...

Nice gun... love the rifling, you buy that off Joel?
If you wanted to improve accuracy, you should have used a longer barrel, I find that 1-1.5 meters works best, cause now you are probably not using the whole chamber's worth of air (hence not getting maximum spud, or carrot, velocity) Other than ...