SpudFiles

Hey guys

I'm getting over piston cannons... The results just can't beat my old style sprinker valve gun. I really don't think it's the piston thats the problem. It works fine but.... The results just aren't as good as my 1st few sprinker valve designs. I think it's due to the fact that I'm using a 1in valve and a highly modded blowgun for a 15mm barrel. No matter what, the max amount of flow is gonna go through the barrel.

This avo I just got bored and so I pulled all my cannons apart and this is what I came up with.... My most comfortable design to date....The bottle fits perfectly as a stock and it's very nice to hold at the elbow.

....and with my pull-pin pop-off valve soon to be used instead of the blowgun, soon to be my strongest.

looks good your pull pin trigger set up is going to be nice. i think that sprinklers are about the same as pistons on small bore barrels, like 1" or less. however if you want to go bigger than a 1" barrel a piston would be much better suited.

BTW how do you attach your soda bottle? i always ask this and every body does it different

I just used a 3/4 to 1in Brass Reducer. I filed off the thread on the bottle and screwed the bottle straight in. Because I used a metal fitting, the thread on it just cut straight into the plastic perfectly. It's always been my method for my cannons. It seals perfect, looks clean, it's easy as hell to make and it never fails.

Thanks alot,

Mitch.

That gun looks great, I especially like the mod with the pop off valve.

Isn't that a pressure relief valve which pops up anyway under a set pressure?

Yeah, but if you use say a pop-valve with a 150PSI limit, and only fill the chamber to 140PSI, then you have a trigger.

I have used a pop-valve for an oly sniper of mine. They work great, are comfortablke and look clean.

Dude, this is an awesome gun, I want some damage pics! Your cannon kind of reminds me of this:

http://www.airsplat.com/Items/GR-HGBB-196LW.htm

YAY: 100 posts!!

Haha thanks alot for all the comments guys. I'll get some damage pics asap when my parents leave for work

Infernal Maveric - Is there anyway I can see your sniper that has the pop-off valve on it? Is it on spudfiles?

Thanks alot,

Mitch

I feel your pain man... I'm no good with piston valves. Premade valves are great for us lazy types.

At first glance, your gun resembles a paintball gun because of the configuration. I like it.

Edit: Soda bottles are scary. If I had cash to spare I'd almost consider just sending you a PVC chamber. But, whatever floats your boat I guess!

Yeah thats one of the next things i'm gonna change but it's gonna be hard getting a pcv chamber like the bottle. It's the perfect size n shape to make it comfortable as hell. I have some 32mm pipe that would make a good chamber. I'm just thinking up a way I can hook it up but still have the same feel as a stock dish out the same performance.


I got some damage pics up. They were done at a range of about 15m at 80 or so psi.

Flip thats a cool gun! I really like how it resembles a paintball gun too. Just two questions, how long is your barrel and what did you shoot in the pictures?
Nice work though!
Peace

The barrel is roughly 60-70cm long. I'm not too sure. I plan to lengthen to it about a meter. It's 15mm so I use marbles. they fit pretty darn well.

Thanks alot,

Mitch.

That should be cool! You can play around on GGDT to find your optimum barrel length i guess. I love that program!

btw, where do you come from because you use mm not inches!? Its so nice for a change! (Im in RSA)

Hi Mitchza89

Is there nothing you do to get a seal when screwing those bottles into 3/4"?

I just tried it. It didn't seal so well for me.. not with teflon tape either. The bottles here seem to be the same size as yours.

Do you think your seal is at the front (where the top of the bottle meets the bottom of the brass fitting) or where the flange on your bottle meets the outer end of the fitting? Do you use teflon tape? Did you test for small leaks in a water bath?

Thanks
Soren

I'd imagine that you filed a little too much of the old thread off the bottle. I made that mistake quite a few times when I had only just gotten into cannons. You have to have enough thickness on the bottle so when you turn on the brass fitting, it's thread bites into the plastic. You don't have to completely file the bottle smooth. Just enough so the bottle fits into the opening of the fitting and bites in when you turn it.

Also, when you have the fitting biting well into the plastic, It can be difficult to turn on without crumpling the bottle. I had a end cap with a schrader screwed onto the other side of the brass fitting. Because the thread on the bottle wasn't set yet, it leaked terribley when you pumped any air into it. But when you do get air in, it's a hell of a lot easier to screw the bottle on without crumpling it. Just do 5 pumps and quickly turn the bottle a little more each time untill you get a real good seal. If you dont get a perfect seal straight away from this method, don't worry. some thread tape will fix it.

I hope this will work for ya but if it doesn't, give us another msg and keep at it. Don't give up!

Regards,

Mitch.