Quick Dump Valve

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.
User avatar
dewey-1
Sergeant 3
Sergeant 3
Posts: 1298
Joined: Wed Mar 28, 2007 10:24 am
Location: NE Wisconsin USA

Wed Jan 26, 2011 11:49 am

Labtecpower wrote:I'm thinking of making one, with a friend of mine. What sort of size do you suggest for a first build?
I can send you Techs marshmellow cannon, the one you see that is a 3D drawing. It will be in AutoCad dwg file if you want it.

I created it and if Tech does not mind I can email it to anyone requesting it.

That way you can get accurate dimensions.
User avatar
Labtecpower
Sergeant 3
Sergeant 3
Eritrea
Posts: 1297
Joined: Sat Feb 20, 2010 6:38 am
Location: Pyongyang
Has thanked: 5 times
Been thanked: 13 times

Wed Jan 26, 2011 12:12 pm

That would be great! it's a working concept, and I don't like building things that don't work :wink:
Altough I dont think tech minds about it, because of his tutorials on youtube. But i'll wait for his confirmation :)

And, if building one, I will probably make vent holes on the pilot area of the valve, because I saw the orange shot with the "air spring" effect.
Would this make the valve even faster, and if it does, would it require a better bumper? i'm going to use tempur foam as a bumper, as it dampens shocks great, and is specially designed for an even pressure distribution.

And another question; If I open the valve with a spring, would this improve valve speed even more?
I'm also thinking of making a nose cone on top of the valve to prevent air turbulence. I want the air flow in the barrel to be supersonic.
As far as I know, supersonic airflow behaves very different, compared to subsonic. So, maybe im going to do some calculations with some fluid-dynamics program.
Last edited by Labtecpower on Wed Jan 26, 2011 12:30 pm, edited 1 time in total.
User avatar
Technician1002
Captain
Captain
Posts: 5189
Joined: Sat Apr 04, 2009 11:10 am

Wed Jan 26, 2011 12:26 pm

dewey-1 wrote:
Labtecpower wrote:I'm thinking of making one, with a friend of mine. What sort of size do you suggest for a first build?
I can send you Techs marshmellow cannon, the one you see that is a 3D drawing. It will be in AutoCad dwg file if you want it.

I created it and if Tech does not mind I can email it to anyone requesting it.

That way you can get accurate dimensions.
Confirmation provided. I posted the details to share with the community. Enjoy.

The Youtube video was not a How to Make it. The Youtube video was specifically a How it Works instead so variation can be built as needed.

In addition to the Youtube video, many of the measurements are provided on this site.
Image
Pro
Recruit
Recruit
United States of America
Posts: 2
Joined: Wed Oct 23, 2024 1:01 pm

Mon Nov 04, 2024 10:48 am

This is an intriguing design, but I have one question that I can not find addressed anywhere.

How are the valve core and piston sealed?

Once the piston is retracted with the trigger rod, won't the high pressure air also just escape through the center rod hole in the piston and out the back of the piston rod assembly?
Is the sliding rod sealed with any sort of dynamic o-rings?

Have some additional concerns about the piston rod flying out the back as the projectile.
Post Reply