My first Pneumatic Gun

[Divinitous]

Hey guys. Long time lurker, first time poster.
I've made a few guns before, but nothing more than some 3" PVC and a grill sparker. I've found them to be extremely unreliable and got tired of constantly clicking to get no output. So I made myself a real gun.

I work in construction and get free reign over the PVC leftovers for most commercial jobs.



I named the gun Brutus. It's still not complete, as I'm going to be connecting the gate valve and the pressure input with a single male quick disconnect for in/out. Also a carrying strap, and a nice coat of paint with some labeling.

The chamber is around 25" long and constructed from 6" sched40 (rated for 180psi). From there it's all 2". The sprinkler valve is also 2". Overall the gun stands a little over 6' tall. It's a little larger that I had planned, but I figure that the barrel has to be pretty long considering the large volume behind it.

To make this even better, is I plan to use this while offroading my jeep. In the jeep I have an air compressor that runs offa the engine. So I'll have a constant supply of 160psi @ my disposal.






Note: Thanks "Noname" for your troubleshooting post. I had one hell of an aggravating honk coming from the valve and no idea what was causing it.
http://www.spudfiles.com/forums/sprinkl ... t8780.html

[sjog]

Some of the guys have to use bike pumps, and there you are with air on wheels!!
Did you set up the compressor?
6" chamber that is huge.I have some 6" parts but just cannot make up my mind which plan to go with.
Fill on clean out. Have you had any leaks in that area?

[MrCrowley]

Wow when I first saw the gun I thought it was a 2" chamber with 1" barrel and sprinkler valve and a tiny ball valve

That thing is massive, great job. Love the compressor set up too.

I'll move this topic to the showcase section for you, it's where you posted completed cannons.

[Divinitous]

Some of the guys have to use bike pumps, and there you are with air on wheels!!
Did you set up the compressor?
6" chamber that is huge.I have some 6" parts but just cannot make up my mind which plan to go with.
Fill on clean out. Have you had any leaks in that area?

Yeah, the compressor is a York 210 that was originally made for AC on an older vehicle. It's a popular mod in the 4x4 community cause it can produce 9+ CFM to run air tools, reset beads on tires, or just inflate the tires after a long day of wheeling. You can actually do this on any ac compressor, but the York has its own oil reservoir and doesn't blow any noticeable amount of oil through the lines. Whereas a typical compressor relies on the oil coming back through the AC system for its lubrication.

Well, the clean out sucks to be honest. It leaks like a bastard. I have about six layers of Teflon tape around it, but it still leaks. I chose to use it cause I assumed that with the hole in the center it would make it the weakest part and if anything were to happen any shrapnel would blow forward. Plus when the gun has pressure in it, anyone infront of it is just asking for trouble to begin with.


Do you guys think that the extreme 180° at the end of the chamber may be a problem?

[bigbob12345]

very nice and very big I bet is has some power but just so you know the cleanout cap is DWV and should be replaced immediatly with a pressure rated plug otherwise you are putting yourself in danger anywhere obove 20psi especially with such large diameter pipe.

[Divinitous]

very nice and very big I bet is has some power but just so you know the cleanout cap is DWV and should be replaced immediatly with a pressure rated plug otherwise you are putting yourself in danger anywhere obove 20psi especially with such large diameter pipe.

Silly question, but would a pressure rated plug leak less? This one is nearly 1/4 thick and seems pretty tough. The plug has some numbers D-2665 which I would assume are the ASTM specs, but for the life of me I cannot find what those are without paying $35. Heh.

Mind sending me a link to a 6" plug that you'd suggest?

[bigbob12345]

A pressure rated plug would leak less if at all but i cannot find any place online that sells threaded pressure rated plugs that size they only go up to 4in you may have to just cut off the femate adaptor and use a cap.

[frankrede]

A pressure rated plug would leak less if at all but i cannot find any place online that sells threaded pressure rated plugs that size they only go up to 4in you may have to just cut off the femate adaptor and use a cap.

Or a male adapter+ slip plug

[MaxuS the 2nd]

If the chamber is 25" long, and the barrel is roughly twice the length of the chamber in an over/under configuration, that would mean that it stands at a little over 4', not 6.

Really nice cannon for your first pneumatic, you have great potential.

[jackssmirkingrevenge]

Very nice, but you can half the piloting hose length by having the hose point directly forward instead of bending back first, this will give you smaller pilot volume and better valve opening time.