piston valve design and question

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
JDP12
Staff Sergeant 5
Staff Sergeant 5
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm

Mon Apr 23, 2007 9:32 pm

Hello,

here is my chamber sealing piston valve design.

The piston will be wood, with o-rings and an equalization port.

2 questions for you all here however..

How should I build a check valve for the equalization port?? I did a search and couldn't find anything..

How can I measure the actual pressure of the chamber- the pressure that will actually be used to fire the gun?? Should I just install a separate Schrader valve into the chamber, and not use it to fill the chamber, just to measure the pressure??

<img src="http://i157.photobucket.com/albums/t79/ ... 1177381344">
User avatar
chaos
Sergeant 3
Sergeant 3
Posts: 1205
Joined: Wed Jan 17, 2007 8:31 am

Mon Apr 23, 2007 9:52 pm

Put a nice gauge on it to check the pressure,

check valves are good but to my knowledge can be kind of tricky to make,why not just use a equalization hole? sorry for my knowledge on these check valve things im just not to sure on how they work.

umm just curios why a chamber sealer? if you have access to o-rings and other matirials why not opt for a barrel sealer?

here is what i did for a barrel sealer

Image

hope this helps a little

peace
chaos
User avatar
JDP12
Staff Sergeant 5
Staff Sergeant 5
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm

Tue Apr 24, 2007 6:00 am

Where would I put the gauge? Don't really get that..Would I still just insert it into the actual chamber?

With your barrel sealer..I presume the smaller pipe to the right is the barrel....And the lower part of the T goes to the barrel...Is your plunger not solid? As in it is two rubber like parts, the back one airtight, and the front one sealing the barrel, and just a bolt connecting them?

I might try that...

Maybe I made a mistake when I said check valve..I mean a valve that like closes up the equalization hole so that air can't escape during firing?
User avatar
spudthug
Corporal 5
Corporal 5
Posts: 936
Joined: Mon Feb 26, 2007 9:02 pm
Location: johnsonburg, Pa USA
Contact:

Tue Apr 24, 2007 6:08 am

Where would I put the gauge? Don't really get that..Would I still just insert it into the actual chamber?
insert it anywhere it will be the same pressure throughout the gun
With your barrel sealer..I presume the smaller pipe to the right is the barrel....And the lower part of the T goes to the barrel...
yea the smaller pipe is the barrel but the lower part goes to the chamber


Maybe I made a mistake when I said check valve..I mean a valve that like closes up the equalization hole so that air can't escape during firing?
it wont leak when ur firing as long as u have the equilization hole to the side and not inside the barrel...its easier to grind a groove with a file..a small groove like 1/32"



btw make a barrel sealer there easier and more powerful
Last edited by spudthug on Tue Apr 24, 2007 6:09 am, edited 1 time in total.
4" piston valved cannon-half done..( i spilt my cement...)

Hybrid- 75% done. need to build propane holder and drill/tap sparkplug hole..
User avatar
JDP12
Staff Sergeant 5
Staff Sergeant 5
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm

Tue Apr 24, 2007 6:09 am

so even if I measured the Pressure from the pilot area, I would get the pressure inside the actual chamber due to the hole in the piston?
User avatar
spudthug
Corporal 5
Corporal 5
Posts: 936
Joined: Mon Feb 26, 2007 9:02 pm
Location: johnsonburg, Pa USA
Contact:

Tue Apr 24, 2007 6:10 am

yea u would but build a barrel sealer there better

the pressure would be equal throguht all of the gun that is being pressureized, the pilot, and the chamber, and the piston


goign tot school ill look at this when i get home
4" piston valved cannon-half done..( i spilt my cement...)

Hybrid- 75% done. need to build propane holder and drill/tap sparkplug hole..
User avatar
JDP12
Staff Sergeant 5
Staff Sergeant 5
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm

Tue Apr 24, 2007 7:19 am

K yea I think I'll build the barrel sealer...I won't have to buy as many parts for it to..

Thanks for the schematic chaos, and for the help spudthug and chaos

EDIT: One more question for you chaos, in your diagram you say that you have an air hose somewhere.......Where exactly is that?? I can's see any blue

Ilikeboom
User avatar
chaos
Sergeant 3
Sergeant 3
Posts: 1205
Joined: Wed Jan 17, 2007 8:31 am

Tue Apr 24, 2007 9:25 am

well on my second version i wanted it a lil bit lighter than the first so i used air hose as the center spacer between the washers. have a look for blue on that pic and you will see it.

good to see u went the barrel sealer if you want me to i could make a more detailed drawing.
AmYisroelChai
Specialist
Specialist
Posts: 117
Joined: Thu Mar 29, 2007 10:50 am

Tue Apr 24, 2007 11:04 am

chaos wrote:well on my second version i wanted it a lil bit lighter than the first so i used air hose as the center spacer between the washers. have a look for blue on that pic and you will see it.

good to see u went the barrel sealer if you want me to i could make a more detailed drawing.
Hi Chaos,

If you wold post a more detailed drawing I would appreciate it greatly. The more detailed you made it the less I will waste my time and money trying to duplicate it. Or not. If you don’t mind I will PM you for more info.

Thanks
User avatar
JDP12
Staff Sergeant 5
Staff Sergeant 5
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm

Tue Apr 24, 2007 12:08 pm

Yea Chaos, a detailed drawing would be a big help..Just so I get it right the first time..I came up with a design but I would still like to see your detailed plans.......thanks
User avatar
chaos
Sergeant 3
Sergeant 3
Posts: 1205
Joined: Wed Jan 17, 2007 8:31 am

Tue Apr 24, 2007 12:53 pm

MUHAHAHAHA.... i have followers hehehe nah its kool ya know what ill do ill take pics of the actual components of the piston but i will also do a more detailed diagram.

only problem will be the weight if you guys are using pvc the force of mi piston may damage the housing causing it to crack or shatter :? another problem is that i have acces to a lot more matirials than u guys probably do, also equipment i have access to need machines eg drill press, angle grinder and basic hand tools

so if i do the diagrams and pics it will help you guys build and understand but if you guys are only semi-serious about it you may later on decide not to do it, so i may as well not bother.

It should be getting done next week if i do it, im kind of tied up with skol atm.

so i ask one more time do you want me to do a how to on my piston with diagrams?

think about it before you answer.

peace chaos
User avatar
JDP12
Staff Sergeant 5
Staff Sergeant 5
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm

Tue Apr 24, 2007 1:18 pm

Tools I have access to= drill press, grinder, wood lathe, tablesaw, bandsaw, welder, all automotive tools, sawzall, soldering iron...sanders..and much more..

So yea I am sure I want you to do it, so thanks a lot chaos...I look forward to it..Thanks

Oh and about it being made out of PVC......I may make it out of copper yet...But I haven't decided...I want to make a rifle similar to yours..
Last edited by JDP12 on Tue Apr 24, 2007 5:11 pm, edited 1 time in total.
AmYisroelChai
Specialist
Specialist
Posts: 117
Joined: Thu Mar 29, 2007 10:50 am

Tue Apr 24, 2007 4:59 pm

Thank you Chaos. But for me while i do have access to all tools needed I am only semi-serious. I only have time for a limited amount of projects and I am trying to prioritize them. If I get around to needing your design I will PM you for it. I finish school in 2 weeks.


Although I am a little confused why a barrel sealer vs a chamber sealer would be more powerful. It just seems like the same piston T but upside down? The only difference would be if you had 2 chambers.

Thank you. I may have to do a little more research on the matter.
Good Luck
User avatar
JDP12
Staff Sergeant 5
Staff Sergeant 5
Posts: 1943
Joined: Fri Mar 30, 2007 8:34 pm

Tue Apr 24, 2007 5:13 pm

Yea I am serious about building it....I will be building one for my big spudgun....and for my smaller one....And yea why exactly is a barrel sealing gun better?? A chamber sealing one seems easier to make...

EDIT: As I rethink this....I am not soo sure that I am for sure building it....I may just use your diagram in this thread...so don't start a how-to for me yet..I still have to mull it over
User avatar
spudthug
Corporal 5
Corporal 5
Posts: 936
Joined: Mon Feb 26, 2007 9:02 pm
Location: johnsonburg, Pa USA
Contact:

Tue Apr 24, 2007 8:14 pm

barrel sealing is way easier...u need a tee..and a bushing grinded out for the housing...for the actually piston u need piston material(hotglue) a bolt and some rubber...and maybe and equilization groove...
4" piston valved cannon-half done..( i spilt my cement...)

Hybrid- 75% done. need to build propane holder and drill/tap sparkplug hole..
Post Reply