How to make a Piston Valve

[SwiftFox]

Ok so here's the plan. I have G&P m16 that I wanted to make my own. So i got the idea of making an M203 pneumatic one to mount under the barrel. I have the parts, the 1'' PVC, cement, end caps, and a schrader tire valve. But the ball valve would be very difficult and therefore very impractical to use in a game. Here's the origional plans
http://s197.photobucket.com/albums/aa22 ... uncher.jpg
But instead I was going to make a Piston Valve instead, but I don't know how. I read the wiki one but I don't get it. Can someone direct me in the right direction with either a guide or some pics and materials to get me on the right track?

Thanks

[Modderxtrordanare]

C'mon man, it's posted right at the top of the page.


Piston Valves Explained Visually

[origin unknown]

If you want to make a small launcher to mount under your airsoft gun, I suggest making a small diaphram coaxial made like this:

[SwiftFox]

Can you tell me what those parts are. I get the idea but what are all of the parts that go into this.

[MrCrowley]

Well say your making a piston in a 2" tee with a golfball barrel(1.5" porting) and say a 1/2" ball valve to pilot the piston and a quick connect(qc) to fill.

You need:

2" tee
2" - 1.5"(gb barrel) bushing
2" - 1" bushing
1" - 0.5" threaded bushing
.5" brass fittings to connect to your QC and your 1/2" ball valve.

You may also choose to have a smaller porting inside the tee to make your piston seal easier and have inter-changeable barrels.

Quick diagram I drew awhile back its not perfect as it doens't include a 'sleeve pipe' to get rid of the tee's 'lip' but it has the concept.


This is just a basic setup, may be hard to understand but there have been like 5 topics like this in the past week so just search for them, I know you will get 700 search results but tough sh|t knowledge takes time so just spend an hour or two researching them more in depth.

The wiki doesn't have a great explanation of them(unless its been updated) so search the forum instead.

Just remembered your putting this in an airsoft gun body, may be easier to go with a coaxial design.

[noname]

Origin unknown, why is the diaphragm inside some kind of fat piece in your diagram? That adds a bunch of pilot volume.
SwiftFix, your "diagram" makes no sense at all.

[SwiftFox]

That's why I said I don't know anything about the topic. But the impression I get is that the valve fits on the back of the gun. so I'll just have the piston valve on the back and then the screwon barrels in front.

Also what's the coaxial design?

Just to make so I can give you uys a better picture of what I'm looking for, I have some short 1'' PVC segments with a male thread guled on. But none of the designs would make this possible. I want to make the front barrel threaded so I can make several rounds that can fit on. The rounds are going to be a plastic bag/cotton ball in the back to make a seal and a piece of tissue paper around the front with a rubber band holding it tight it will keep the bbs in, while making little resistance.

I want to make the piston valve in the back able to be filled with a CO2 cartrige or a bike pump or something. Just for your information.



The diaphram valve looks like it would work but I'm not sure about the size I would need to make it compatible with the the 1'' rounds with the threads on them.

Thanks

[singularity]

a coaxial means the barrel is within the chamber kinda like layout of the wire in a coaxial cable(tv cable). for you your best option would probably be a barrel sealing tee similar to the diagram MrCrowley drew. all you would need to do is put a female 1" threaded adapter on the barrel to screw in your "grenades" and drill an extra hole in the back for the schrader valve. if you need me to i can draw you a diagram

PS- is that you Dan?

[spudthug]

SwiftFix, your "diagram" makes no sense at all.

yes it does...its a basic pneumatic.. he pressurizes it with the tire valve, screws on an adition to the ball valve like pre loaded shells with cotton as sabots and paintballs in the middle...

[SwiftFox]

Actually sdudthug was right about the basic pneumatic. I made a couple of these but the ball valve in the middle was really hard to turn while holding the gun up. I was planning to use airosft bbs instead. I've done this many times with larger models but someone suggested a piston valve but I didn't know a thing about them so I came here

I was looking at the diagram but the specs are way to big to fit on the foregrip of my M16. There's no way I could fit half a tennis ball in there.

A diagram would be nice

PS. NO I'm not Dan 8)

[mike1010]

if you want to make it really small and easy to refill on the field take thestandard airsoft grenades(50$) and build a pvc body. all you need to fire it is like a pen sized pin to push the button on the back of the grenade

[SwiftFox]

I was trying to keep the price down in this project. I had the idea of doing that but the price would have killed me.

[SwiftFox]

Ok, so I talked to my friend who is a wiz at stuff like this. He's gunna make me one when I give him the parts.

[SwiftFox]

I got a shopping list from the kid and I had a few questions about the parts I need.

Here's the list

Shopping Cart

-2’’ Slip Coupling

-2’’ to 1’’ slip bushing

-1 ¼ slip endcap

-1’’ slip endcap

-115 saftey pop off valve

-¼ brass threaded tee (female)

-(2) ¼’’ threaded nipples (male)

-Schrader valve

Ok so on the tee, is it ok to make it PVC instead of brass or does it have to be brass? Also what does the safety pop off valve do? And can I get all this stuff at home depot?

Thanks

[mike1010]

well for one the home depot near my house doesn't carry 2 inch pressure rated pipe but osh will. you will need a brass t because they dont really have any small pressure pvc fitting like what you need yours for. a threaded shrader valve is harder try mcmaster dot com.