Metal Piston-Valved Cannon

[Velocity]

<img src="http://www.spudfiles.com/uploader/uploa ... n23432.JPG">

This is my newest cannon. It cost about $20, and was built in about three hours (this includes waiting for epoxy to dry fully). It is constructed of black iron bought from my hardware store.

The main valve is a barrel-sealing piston valve with a 1.25" inlet and a .75" outlet. Right now, there is no barrel, but I plan to get some kind of copper barrel (the reason I built this cannon was so that I would be able to use it in the winter). For now though, I might just pop a 3/4" male adapter on my 5' CPVC paintball barrel, and use that. I'll post an update when I get a barrel on this thing.

Upgrades include: nicer looking QEV, blowgun triggering, and adding a barrel or two.

You might suggest that I shorten up the distance between the reducing coupling and the tee... however, this is the shortest possible length it can be; that size pipe nipple was the shortest that the hardware store had.

All in all, this was a fun project, and will become more fun when winter comes around.

[mark.f]

Let me be the first to say that that is a nifty little gun, (yes, nifty is my word now)!

I need to get ready for winter. I think I might just make a copper gun, though.

[Gnobbes]

The whole project was twenty bucks? Out of curiosity, how much did you pay for the QEV?

Nice, solid gun anyway.
Probably heavy as hell, which is cool too. To me, heavier feels more serious.
How much pressure are you planning on putting in it?

[Velocity]

Let me be the first to say that that is a nifty little gun, (yes, nifty is my word now)!

I need to get ready for winter. I think I might just make a copper gun, though.

Thanks, I have wanted to build a copper gun for a while. My last five cannons (starting with the BS paintball rifle, to this one) have all been simple time-consumers until I build a copper gun. Problem is, I do not know how to sweat copper together (yeah, spudwiki I know), and I doubt my parents would let me "mess around" with a propane torch.

Quick question: I need to attach a copper male adapter to a length of copper pipe for the barrel. Considering that I do not know how to sweat and probably won't be able to learn, would it be ok to just use epoxy? Its not like the barrel is holding any serious, extended pressure.

The QEV cost $20, but I bought it a long time ago; over a year ago, in fact. It was not included in the cost.

How much pressure? Hmm...

The maximum I have ever gone up to with a PVC cannon is 80 PSI; I did this with an anti-siphon sprinkler valve pneumatic and a dual supah+ pneumatic. I usually only take my guns up to 60 PSI max (some of them don't even see above 40 PSI... I build them as fast as I test them )

Im planning to go right around 100 PSI to 120 PSI, for these pressures are relatively "safe" for a metal cannon (or so I believe)

[Infernal Maveric]

nice looking cannon (so far). A copper barrel would realy make it fun for the winter.

about epoxy oposed to sweating. Personally, I'd solder/sweat it, as its a GUARANTIED joint, unlike epoxy which may crack.

All you need to do is rub down the section of pipe you want to solder the fitting to with WIRE WOOL, and the same with the inside of the fitting. Then runb FLUX arounf both the parts you rubbed with wire wool. Fut fitting ito desired place on pipe and put the pipe/fitting into something secure and non-flamable. Heat pipe with BLOW TORCH tuntil you see the flux dissapear, and the sopper go a pinkish colour. Add a few dabs of SOLDER around the fitting. The heat will make it be "sucked" around the fitting. let it cool and your done.

[POS]

see my gun, it is soldered (the MB1)

You could easily use a pressure of 200 psi, even 300. It is strong material you use. Just watch out you dont blow the QEV.

Question, the nipple on top, is it used to fill the gun ? How do you trigger the valve ?

[Gnobbes]

I would definitely solder the copper tubing. It's actually really easy to do, and propane torches are pretty safe as long as you're not playing recklessly with them. Basically they're just overgrown butane torch lighters.

Depending on the PSI rating of that QEV, you could probably hold a lot of pressure in this gun. Get the right chamber/ barrel ratio, and you've got a little monster.

Make sure to post when you finish it up. I'd definitely like to see how it turns out.

[PVC Arsenal 17]

so the whole thing is 1 1/4? What is the piston?

[schmanman]

been gone salmon fishing. first post in a while. Very nice gun! what did you use as the piston, and what does it seal on?

[Velocity]

The piston is made from a 3/4" endcap, and it seals against a combination of a 3/4" pipe nipple/3/4" coupling.

I did a bit of an upgrade by adding a better QEV, along with a blowgun with an air hose. Makes it very ergonomic

I'll try to get the barrel by friday, but I can't promise anything right now...

[PVC Arsenal 17]

a PVC endcap? or copper?

I can't believe you posted this cannon. I'm working on one almost EXACTLY the same as yours.

[POS]

Does that mean that you ar going to build one like that ? Or do you have already pics of yours ?

[PVC Arsenal 17]

I didn't build it yet I had the same idea in mind. Over/under 1 1/4" steel piston cannon. When I invisioned it, it looked just like his!

[Velocity]

I bought the copper barrel (expensive! $15 for 3' (including the male adapter)). It is 3/4". Despite the common sense of everyone on this forum, I decided just to epoxy the barrel on, for simplicity's sake. I put the barrel on, and it looks pretty sweet (if I do say so myself ). Pictures will be up later today/tommorow

[PVC Arsenal 17]

What is the piston made of? Steel, copper, PVC?