diaphragm coaxial sprinkler exhaust cannon

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
hi
Staff Sergeant 2
Staff Sergeant 2
Posts: 1619
Joined: Thu Feb 01, 2007 9:28 pm

Mon Jul 02, 2007 5:15 pm

i did it because i couldnt find anything else.

thanks for all the good comments. and as for those of you who didnt say anything....... just kidding
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
e1337
Specialist
Specialist
Posts: 110
Joined: Mon May 28, 2007 8:00 pm
Location: Florida

Wed Jul 04, 2007 3:58 pm

How does the valve work in the Union? Also The cannon looks great.
User avatar
hi
Staff Sergeant 2
Staff Sergeant 2
Posts: 1619
Joined: Thu Feb 01, 2007 9:28 pm

Wed Jul 04, 2007 4:13 pm

e1337 wrote:How does the valve work in the Union? Also The cannon looks great.
did you just say it looks good so i would answer your question? just kidding.

it works ecactly like a sprinkler valve does. the diaphragm it self works like a piston. when it is filed the diaphragm mover foward and seals, when it moves back it opens.

there is about 1 cm between the barrel and daphragm when it is not pressureized, but when pressureized it seals the barrel.

edit- the union just has a peice of rubber in it and nothing else.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
e1337
Specialist
Specialist
Posts: 110
Joined: Mon May 28, 2007 8:00 pm
Location: Florida

Wed Jul 04, 2007 4:27 pm

Is there an equalization hole in the rubber or do you fill both sides with sir?

EDIT: Sorry read it over and understand now.
User avatar
spud yeti
Sergeant
Sergeant
Posts: 1030
Joined: Tue May 08, 2007 1:41 pm
Location: Cape town south africa
Contact:

Thu Jul 05, 2007 11:06 am

there is an equalisation hole as far as I know
really good quote/phrase here
User avatar
hi
Staff Sergeant 2
Staff Sergeant 2
Posts: 1619
Joined: Thu Feb 01, 2007 9:28 pm

Thu Jul 05, 2007 11:59 am

nope, that is yet to be added. i was thinking to poking a hole in it, but i thought it would rip, so im putting a small tubee that goes on the out side that will have a ball valve on it.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
User avatar
Panzerfaust
Specialist
Specialist
Posts: 129
Joined: Tue Apr 17, 2007 4:37 pm

Thu Jul 05, 2007 1:20 pm

Nice gun! I am surprised that your rubber diapraghm can stretch far enough to reach the barrel, but if it works then i guess im wrong. Is that a sch. 80 union? i always wondered if unions where pressure rated... A couple people where asking for how you stabilized the barrel, i found a very good way to do it. Buy a reducing bushing that takes your barrel size to your chamber size. Look on the smaller pipe side of the reducer and you will see the hole that the smalle pipe goes into with several spokes (Sp? spokes like on bike wheels) radiating out from it. Remove this hole and the spokes connected to it, you will now have a piece that your barrel fits into (sand it out so it fits through) and the outside edges of those spokes will fit perfectly into the inside of your chamber.
User avatar
hi
Staff Sergeant 2
Staff Sergeant 2
Posts: 1619
Joined: Thu Feb 01, 2007 9:28 pm

Thu Jul 05, 2007 1:47 pm

yes, it a sch80 unon, pressure rated to 150 psi.


i like the idea on centering the barrel, it would require a lathe, but would work..

i already centered it with an end cap, but i might do this if i build another coaxial.
"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
User avatar
Panzerfaust
Specialist
Specialist
Posts: 129
Joined: Tue Apr 17, 2007 4:37 pm

Sat Jul 07, 2007 3:13 pm

Lathe? Ha! i hacked it in half with a hack-saw and then used the same hacksaw to cut out the internal section with the spokes. Easy as pie. I have essentially no power tools but have been amazed how many different tools some ghetto ingenuity can replace. It fits perfectly, too.
User avatar
frankrede
Sergeant Major 2
Sergeant Major 2
Posts: 3220
Joined: Thu Jul 20, 2006 9:47 pm
Has thanked: 1 time
Been thanked: 1 time

Sat Jul 07, 2007 3:23 pm

Awesome, nice clean construction!
Current project: Afghanistan deployment
User avatar
Panzerfaust
Specialist
Specialist
Posts: 129
Joined: Tue Apr 17, 2007 4:37 pm

Mon Jul 09, 2007 1:08 pm

I am thinking of making a pistol or something out of this design. I dont have any rubber sheet though. Do you think the some neoprene (old mousepad) would work? i think it would be thick enough that an equilization hole wouldn't cause it to shread.
User avatar
noname
First Sergeant 4
First Sergeant 4
Posts: 2698
Joined: Mon Apr 10, 2006 9:19 pm
Location: Bay Area, CA

Mon Jul 09, 2007 1:49 pm

I made a diaphragm pistol that I'll post sometime, and I just used 1/8" sheet rubber. It holds 120 psi, doesn't require an equilization hole, and is able to exhaust well through just a blowgun.
<a href="http://www.spudfiles.com/uploader/uploa ... .jpg">Here it is!</a>

I don't think a mousepad will work, but you can try it if you want.

Hi, how does it equalize without a hole? Did you take the O-ring out of the union?
User avatar
mopherman
Corporal 3
Corporal 3
Posts: 788
Joined: Sat Feb 03, 2007 8:20 pm
Been thanked: 1 time

Mon Jul 09, 2007 1:57 pm

nonam, what kind of plug is that? is it hollow or does it cut off at the bottom?
User avatar
noname
First Sergeant 4
First Sergeant 4
Posts: 2698
Joined: Mon Apr 10, 2006 9:19 pm
Location: Bay Area, CA

Mon Jul 09, 2007 5:30 pm

It's a 2" male threaded plug. It's basically a pressure rated cleanout cap. It's hollow; if it was solid it would cost a load.
User avatar
mopherman
Corporal 3
Corporal 3
Posts: 788
Joined: Sat Feb 03, 2007 8:20 pm
Been thanked: 1 time

Mon Jul 09, 2007 5:56 pm

noname wrote:It's a 2" male threaded plug. It's basically a pressure rated cleanout cap. It's hollow; if it was solid it would cost a load.
i know its hollow, but mine have deep valleys in them instead of a flat surface. sorry for the wierdly worded post.
Post Reply