SpudFiles

Hello all! This is my first post and I'm quite excited about this site. My usual builds are combustion and a few sprinkler valve pneumatics but I have decided to change it up. My idea is a semi auto all metal gun with-


Chamber: 300psi(what material metal?/size?)

Valve: 1/2" QEV with spring loaded piston w/ hammer valve blowgun(material for piston?/blow gun brand for actuation?)

Barrel: breech load 1/4"


I know Im new and a load a questions is super annoying but I promise to contribute to other forums and answer questions!

Thanks for all the help and such a wonderful community!

-ANDREW

Welcome to spudfiles

AnotherSnappedLine wrote:I know Im new and a load a questions is super annoying but I promise to contribute to other forums and answer questions!

Answering good questions is usually a pleasure, it's answering questions that have been repeatedly asked before and could easily be answered using the search function that gets annoying

(what material metal?/size?)

What's your budget? What are your metalworking skills/facilities? How many shots do you expect to get from a full chamber?

(material for piston?)

Comes with the QEV, no worries.

(blow gun brand for actuation?)

While not officially rated for it, most blowguns will happily take 300 psi if mounted in the correct orientation.

Wow thanks for the quick replies!

I don't have a lath at the momemt so store bought is my limit.
My budget is about $100.
I was thinking about building a spring-loaded piston QEV, but are the store bought ones semi?

[/quote]

also 5 shot is what i hope for

Store bought QEV's can be used as single, semi, and full auto firing valves. The determining factor is the pilot valve/fill valve setup. Another factor you'll have to address is ammo loading. A semi automatic valve setup with a single shot breech load configuration is a single shot gun.

I think I've got it figured out...
Loader-Gravity fed hopper
Barrel- 1/2"
Valve- spring loaded QEV
Actuator- Hammer Valve regulated blowgun
Chamber-(what is ideal for a 300 PSI 5 shot?)

AnotherSnappedLine wrote:Hammer Valve regulated blowgun

What the hell is that?

Chamber-(what is ideal for a 300 PSI 5 shot?)

Best bet is a huge galvanized nipple or copper.

Gun Freak wrote:

AnotherSnappedLine wrote:Hammer Valve regulated blowgun

What the hell is that?

Chamber-(what is ideal for a 300 PSI 5 shot?)

Best bet is a huge galvanized nipple or copper.[/quote]

I meant one end of the blow gun is hooked up to the outlet as normal; on the other end, is a threaded reducer from whatever diameter the blowgun is to a 1/2 of that. Before I twist in, I will slide a screw and spring to it. Therefore, when the air is rushed out, the screw slides down and blocks anymore, allowing the piston to spring back shut.

Ah. I see. I haven't read up on the whole thread but in order for that to work you need to poke a hole in the QEV piston and add a spring, which I assume you already know.

Gun Freak wrote:Ah. I see. I haven't read up on the whole thread but in order for that to work you need to poke a hole in the QEV piston and add a spring, which I assume you already know.

Or I could build my own with a 3/4" T 1/"2 Quck Connect and Epoxy piston. Less chance of a catastrphic mistake...

That works too, but for a noob ( ) it would probably be easier to just buy one, not to mention more reliable than a homemade one. Your first piston valve probably wouldn't be ideal for use in a semi unless you really know what you're doing.

Any recommendations on brand? I've been searching around but cant find a top choice.

i would check ebay for quick exhaust valves

I was able to get 7 1/4'' QEV's sent to my house for about 35 USD.


Try and find this design, i have taken mine well above 300 psi both semi, and full auto with no issues.

sweet! thanks ill check it out