Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
nathan9117 wrote:Okay so I just got a hand pump for now to test things out while I wait for my fridge compressor to be welded or soldered to a better output pipe. I filled the small fire extinguisher tank to 4 bar and used an adjustable wrench to hit the hammer valve I can get about 10 decent shots out of it. This gave me some ideas as to improvements for the overall design. I want to replace the fire extinguisher tank with either a pcp rifle air chamber or something stronger like a paintball tanks as I really dont want to risk blowing the tank when pumping it to 10 bar or something. The next part ideally would be to put a regulator between the air tank and the hammer valve so that each shot will be equal and I wont end up with 2 100 psi shots then 1 crappy 40 psi shot thats only an example but you get the idea. Cheers I will work on the hammer today.
Hammer valves are self regulating, so even when there is a pressure differential they will let out almost the same amount of air. This is because under high pressure the valve closes faster due to the higher force, and when there is low pressure, the valve is open longer because the air isn't pushing on it as hard.
I wouldn't worry about replacing the fire extinguisher... I use mine at 150 psi all the time and yours looks to be even stronger than mine. But if you go with a copper air chamber or even a large threaded nipple you could use over 400 psi. This will be nice when you get your fridge compressor up and running
nathan9117 wrote:Okay so I just got a hand pump for now to test things out while I wait for my fridge compressor to be welded or soldered to a better output pipe. I filled the small fire extinguisher tank to 4 bar and used an adjustable wrench to hit the hammer valve I can get about 10 decent shots out of it. This gave me some ideas as to improvements for the overall design. I want to replace the fire extinguisher tank with either a pcp rifle air chamber or something stronger like a paintball tanks as I really dont want to risk blowing the tank when pumping it to 10 bar or something. The next part ideally would be to put a regulator between the air tank and the hammer valve so that each shot will be equal and I wont end up with 2 100 psi shots then 1 crappy 40 psi shot thats only an example but you get the idea. Cheers I will work on the hammer today.
Hammer valves are self regulating, so even when there is a pressure differential they will let out almost the same amount of air. This is because under high pressure the valve closes faster due to the higher force, and when there is low pressure, the valve is open longer because the air isn't pushing on it as hard.
I wouldn't worry about replacing the fire extinguisher... I use mine at 150 psi all the time and yours looks to be even stronger than mine. But if you go with a copper air chamber or even a large threaded nipple you could use over 400 psi. This will be nice when you get your fridge compressor up and running
Haha thanks for the good words and yeah im gona ask my mate next door to weld a tube on so i can use my quick connect fittings. Once i get a decent air supply i will be able to test higher preasures. I plan to get my head in gear and build a trigger and sear and pistol grip and even cut the tube and hammer etc. Cheers
. But and here is the main problem I am having. I need someone to help me on how I would build a very simple trigger mechanism that has a bolt and trigger so that each time I cock the bolt and shoot it strikes the hammer valve on the fire extinguisher causing the round to be fired such as a pellet or small BB.
i made it, but i only load the hammer. the problem with this valves is that they have a large area and you need a pretty strong spring witch is kind of hard to handel . but it works pretty good.
here is my video. i didnt finished the gun cause i don't find a good barrel for it,.
the fire extingusher if you read on that bronze cap is 30 bar rated, that means you may put 40 bar with no problem.
[youtube][/youtube]
and yeah im gona ask my mate next door to weld a tube on so i can use my quick connect fittings. Once i get a decent air supply i will be able to test higher preasures. I plan to get my head in gear and build a trigger and sear and pistol grip and even cut the tube and hammer etc. Cheers
