SpudFiles

I'm not a combustion guy but pictures would be good

Sure thing I’ll post a pic of 2 of my 3 spud guns.

It might be a while because I’m currently away from a proper computer and the editor doesn’t work very well on an iPhone.

Ok here’s a picture of my first 2 potato cannons. The big one was my first one the small one was my second. They’re both solid core abs. I get my abs from home hardware, Home Depot where I live only has cellular core abs for some reason.

The tape on the chambers is for grip.

Primitive but still fun what's your ignition like and are you metering your fuel in some way?

My ignition is two small nails and the piezoelectric thing from a bbq lighter. They work pretty well and I use hairspray or deodorant in them. If anyone knows of a better fuel let me know.

I could send a picture of my third combustion and when I finish it my first pneumatic.

First pneumatic is built I will post pictures tomorrow if anyone want me to.

Potato Demon wrote:If anyone knows of a better fuel let me know.

syringe metering ftw!

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I haven’t tried syringe metering yet, I just count to 10 quickly and then stop spraying. I just made a spud gun with a 4”x1’ combustion chamber and a 1 1/2” x 3’ barrel btw.

Potato Demon wrote:First pneumatic is built I will post pictures tomorrow if anyone want me to.

Yes, I likes pneumatics

Ok here is a picture. I’m waiting for the cement to set (transition cement). The only reason I built it with ABS is because I had some scrap. I know that abs isn’t the best for pneumatics but if it fails it ruptures and I could probably salvage the valve with a saw and a core drill bit (or whatever it’s called). This is solid core abs by the way. I used the valve from some scrap inner tube and drilled a hole in the chamber that was smaller than the valve, then I put the valve into my drill and held it to the hole and turned on my drill. Because of the rubber on the valve it fit perfectly. I added a ton of hot glue just to be safe.

So the ball valve is the trigger? They work really well when spring loaded, then you can have a better trigger

I was actually trying to figure out how to spring load it. What I have done to make it easier to turn (haven’t got around to firing it yet) is I put a thin layer of Vaseline in the ball valve and that seems to help a little.

You'll need to make some kind of linkage. Attach a spring to the valve handle somehow, maybe need to extend the handle? then someway of locking and releasing the handle or spring.
This is one I made but it did get complicated