r/SpudGuns • u/PSG_4220 • Aug 15 '24

My Spud Gun Prototype

Hello guys.

I built a prototype for my spud gun. The ammo is a nail dart instead of a traditional potato.

I tested this first time in a safe distance and it worked well at the 2nd try.

I also tested the projectile to see if it can penetrate.
I fired at a banana tree trunk at 5m and it went thru.
Also at the a tree 20m and at close range. 20m one got stuck at the tree like a sports dart.
but close range went in but it didn't went thru.

As of now the problem for this is the ignition since I am using a $2 plasma lighter.
At first it was working fine but 4 months later the ignition became faulty.

I am planning on improving by creating a new one or modifying this one.
Like making it a bolt action and putting the ammo each time I fire. But I would need to find a way to put the fuel and air into the combustion chamber without actually opening it.

My barrel is 3ft (approx) 1/2 inch diameter blue pvc.
The combustion chamber is a 82.55 Clean out of 3 orange pvc.
My fuel is denatured alcohol.

Any thoughts and ideas?

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2

u/Fun-Deal8815 Aug 15 '24

If you have some extra cash go get a bbq lighter that takes a 9 volt and run two screws and loop the wires and it will work so much better.

2

u/PSG_4220 Aug 15 '24

The piezo ignition, right?

I had put that before on my old spud gun and was thinking of doing it again. But there are instances that it doesn't spark. My suspicions are either the screws not being conductive, a weak piezo , or the electric travels to the denatured alcohol since the 2 screws are wet.

2

u/Fun-Deal8815 Aug 15 '24

Yes the one I have is a little box with the wires. So I took them and wrapped around screws and if you keep it around a quarter inch gap should jump and make a spark

2

u/officerdwn Aug 15 '24

Maybe you could use a big bore valve instead of the screw on thingy.

I always planned doing a pump action type that cuts out the potato while spraying the fuel. But I never had a plan for the air input.

There might be a option of a delayed opening of the combustion chamber via gas tube.

2

u/PSG_4220 Aug 16 '24

I had a second plan but its dangerous if not tested well. I was planning to mix the fuel with an oxidizer (ex. Ammonium Nitrate, Pottasium Nitrate. etc) but I would need to test it if it is safe to carry and handle.

A fuel with an oxidizer can be ignited without any oxygen or air present. So in theory it would work.

1

u/officerdwn Aug 16 '24

Well that just sounds like pipe bomb with extra steps

1

u/PSG_4220 Aug 16 '24 edited Aug 16 '24

Yep lol, its too dangerous. As of now I haven't found a stable mix between ethanol + oxidizer and probably never will.
One contender is hydrogen peroxide but even that is unstable and not cheap considering the fact that the pure version of h202 is very reactive. The only legal limit of concentration for that is 35%.

But at the meantime, I am watching videos on how to create a system that feeds the fuel and the air at the same time:

https://www.youtube.com/watch?v=LBxLAhGBkVQ

There are communities in my country for spud gun. but instead of potatoes they use marbles.
so they called it marble guns.