My First Metal Gun

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.
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KurlyQ
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Fri Oct 16, 2009 1:42 pm

My first metal gun I've created.
It's all a product of having too much time on my hands after a day of mid-term finals.

Specs:
Barrel: length: 6" long, 1/4" diameter
Pressure chamber: 4.5" long 1/2" diameter
Valve: 1/4" ball valve

I was wandering around the hardware store, and I was looking to create an extremely small hand held pneumatic spudgun that I could construct in one day, and that was when I came across the steel plumbing parts. I tinkered around a bit, and came up with this. Not too pretty, but it does it's job.
My main problem was finding a way to get a Schrader valve into the pressure chamber. I eventually ended up just shoving a tubeless tire valve into a 1/2" to 3/8" reducer, and putting an o-ring behind it. It holds pressure, but I'm slightly worried about it flying out sometime. has anybody else done this with their design? and if so, is it pressure-worthy?
I'm thinking about making this into a piston gun and putting a longer, skinnier barrel onto it, but that will have to wait.

Also, what pressure do you think I can take this thing too?
Attachments
The whole cannon
The whole cannon
gun in hand
gun in hand
close-up of the schrader valve assembly
close-up of the schrader valve assembly
Last edited by KurlyQ on Fri Oct 16, 2009 3:45 pm, edited 1 time in total.
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boyntonstu
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Fri Oct 16, 2009 1:58 pm

KurlyQ wrote:My first metal gun I've created.
It's all a product of having too much time on my hands after a day of mid-term finals.

Specs:
Barrel: length: 6" long, 1/4" diameter
Pressure chamber: 1/2" 1/2" diameter
Valve: 1/4" ball valve

I was wandering around the hardware store, and I was looking to create an extremely small hand held pneumatic spudgun that I could construct in one day, and that was when I came across the steel plumbing parts. I tinkered around a bit, and came up with this. Not too pretty, but it does it's job.
My main problem was finding a way to get a Schrader valve into the pressure chamber. I eventually ended up just shoving a tubeless tire valve into a 1/2" to 3/8" reducer, and putting an o-ring behind it. It holds pressure, but I'm slightly worried about it flying out sometime. has anybody else done this with their design? and if so, is it pressure-worthy?
I'm thinking about making this into a piston gun and putting a longer, skinnier barrel onto it, but that will have to wait.

Also, what pressure do you think I can take this thing too?
My cannon without an o ring is good to 500 psi at least.

Make the hole barely large enough to stuff it in there.
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maverik94
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Fri Oct 16, 2009 2:06 pm

Ok, a few things.
1) I am a big fan of full-metal guns, and even though ball valves don't have great performance, this gun looks like it was a great way for you to learn about construction using metal parts.
2)About puting in the schrader: I would get what's called a "clamp-in schrader", you can get them at most auto parts stores, all you do is drill a hole in the end cap (like you did) remove the nut and steel washer, put the valve in from the inside , with the rubber against the cap. Then you just replace the washer and tighten the nut, and it makes a perfect and safe seal. You really want to do this, it is cheap, easy, and might save you an injury or worse, LEAKING :o :o Just kidding, but seriously, do this!
3)
Pressure chamber: 1/2" 1/2" diameter
I am assuming you mean 6" of 1/2" pipe?
4) I would feel confident taking this gun to about.....40 psi, untill you change the schrader. Then I would feel confident taking it to about 400 psi

Overall, a very simple, but clean build. Just change that schrader valve and you should be fine! Happy spudding!
Last edited by maverik94 on Fri Oct 16, 2009 7:07 pm, edited 6 times in total.
"You can't be friends with anyone if you aren't friends with yourself."
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Give me a lever long enough, and a fulcrum on which to place it and I shall move the world.
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Current Project: None, I'm in Spudremission.
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psycix
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Fri Oct 16, 2009 3:19 pm

It's simple and reliable, I give you that.

You can take this to a fairly high pressure. 500 psi+
Till the day I'm dieing, I'll keep them spuddies flying, 'cause I can!

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suburban spudgunner
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Sat Oct 17, 2009 2:10 pm

A friend of mine made something similar to this...he called it the Power Stick.

I would say your working pressure depends on the schrader valve. I've had them blow out at 200 psi (but that's probably because I bought the cheap ones).
The definition of insanity is doing the same thing over and over again and expecting different results.
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psycix
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Sat Oct 17, 2009 6:00 pm

However, blowing out the shrader doesn't trigger the pilot, but simply vents the chamber :)
Relatively safe if you ask me.
Till the day I'm dieing, I'll keep them spuddies flying, 'cause I can!

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jackssmirkingrevenge
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Sat Oct 17, 2009 6:13 pm

suburban spudgunner wrote:A friend of mine made something similar to this...he called it the Power Stick.
Are you sure he was talking about a launcher :roll: :D
hectmarr wrote:You have to make many weapons, because this field is long and short life
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maverik94
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Sat Oct 17, 2009 9:50 pm

I mean, for all I know that could be safe up to 500 psi+, but I just think it would be safer putting in a clamp-in schrader, but do whatever you want, after all, it's your gun man!
"You can't be friends with anyone if you aren't friends with yourself."
"I'd rather be hated for who I am, than loved for who I'm not." -André Gide
Give me a lever long enough, and a fulcrum on which to place it and I shall move the world.
–Archimedes
Defeat is always momentary.
–Carl Denham

Current Project: None, I'm in Spudremission.
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Technician1002
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Sat Oct 17, 2009 11:35 pm

If you use a tire valve the way it was intended, they hold pressure very well. Get a pipe cap and drill it for the stem with a hole the same size as a rim it is normally installed in.

Here is one I put in a 1/4 inch brass pipe cap. To get it to fit, I had to trim the rubber to a smaller size, but I've not had any trouble. I use this one to 110 PSI with no issues.
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SpudBlaster15
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Sun Oct 18, 2009 1:46 am

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Last edited by SpudBlaster15 on Wed Jul 14, 2021 7:12 pm, edited 2 times in total.
Pascal123
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Sun Oct 18, 2009 5:07 am

I think you should turn the T fitting, that the shrader valve is aiming towards so you can not damage the valve if you put the back of the gun on the ground. Also the hole of the fitting were you put your shradervalve in should by much smaller. Just cutt off the big rubber end of the valve if it doesnt fit. I use a shrader valve to and easyly pump it up to 15 bars without issues. Even a bit of force to the valve to disconnect your pump wouldnt be any issue.

I hope you understand me a bit:P, im from the netherlands so you might not understand somethings:P.

gr pascal
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