SpudFiles

This is my first spud gun of any kind so forgive me if it seems very "ghetto".. or ugly. I built it mainly to be a learning experience, and hope to use what I have learned on this build to make a much prettier cannon next time.

So, here she is:


As you can see I used an under/over design similar to that of Desert Storm. This allowed me to have the barrel and chamber much closer together for a more compact gun. I also just really liked the design. I know the pilot volume is big, it's that far back to give the ball valve handle some room, and to make aiming easier.




The ammunition:
My main ammo is 13.5mm ball bearings that fit perfectly in the barrel.
I also use a crude dart made from a bolt, some nuts and electrical tape which fits surprising snugly in the barrel.




Now for the all important damage shots

Yellow pages shot from five meters with a ball bearing at about 70PSI.
Over 600 pages of penetration.


The table seen in other pictures shot with a ball bearing (left) and bolt (right). The BB passed right through like it was butter leaving a huge exit wound. The bolt didn't completely exit, stopped by it's large back. These were also both at 70PSI.


All for now, I'll get more damage shots when I crank the pressure up.
That should be as soon as I can find a decent backstop. The destructive power at a mere 70PSI has shocked me somewhat.

Looks really good for a first but jsr is gonna get on you for your relatively large pilot volume. Other than that great first.

Nice job! Take some steel wool and shine it up.

Welcome to Spudfiles.

jor2daje wrote:Looks really good for a first but jsr is gonna get on you for your relatively large pilot volume.

... and large chamber volume, and using it at just 70psi!

If you think the power is good now, up the pressure you can get away with a much smaller chamber, typically a ratio of 1:1 chamber:barrel volume is a sufficient balance between power, noise and efficiency, and as was pointed out above, the smaller the volume behind the QEV the faster it will open.

Very nice cannon looks kinda big and maybe a small front handle in the front of the gun would help it alot.. well that might just be me but I dont link touching copper pipe beacause it leaves a nasty smell on my hands and sometimes dirt... Or you can sleeve the pipe in some fom and make it look cooler too ... Good job on a first cannon thought and please do some high pressure tests on this cannon

P.S: jsr you got some email

this is a beast

try to make trigger for it , and if you have method to higher pressure please post some videos

Actually nice work for your first, heck even if it were your 4th or 5th...or 10th... Why such a long pilot tail piece at the rear?

The barrel is about 2ft longer than the chamber, I know while the chamber/barrel ratio is far from perfect, it is a little better than the pictures make out. That was all the pipe I had and rather cut off a relativity small piece I decided to leave it be.

Again, the pilot hangs out that far to make operating the ball valve easier- I was hoping the ball valve would have such flow that the effect of a few extra cm would be minimal.

The pilot set-up is far from ideal. I'd love to have it operated by a blowgun, but the costs started to mount up (as it was my first build I had to buy tools like a torch, flux and solder as well as pipe and fittings).

far_cry wrote: if you have method to higher pressure please post some videos

I have the means, but over penetration is really an issue in my modest (small) English garden. The last thing I want is for a ball bearing to work it's way into some old dears living room. I'll try and get some old carpet and see how that holds up. Safety first 'n' all that!

starman wrote:Actually nice work for your first, heck even if it were your 4th or 5th...or 10th...

Cheers, means a lot. Hopefully I'll be able to come up with nicer creations in the future too.

jrrdw wrote:Welcome to Spudfiles.

Thanks

i have yet to expirement with copper pipe...this makes me want to try it out and blow a few bucks on one hahahah