tshirt 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.
Wizard
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Fri Jul 27, 2012 11:01 pm

I used a female stabilizer from Palmers Pursuit to connect my HPA tank to my launcher and then used macroline to plum the air into the chamber. Its all rated for standard full pressure HPA tanks on paintball guns and the stabilizer lets me bring the PSI down to 100 where I wanted it.

ETA: Once I finish mine I will post up some pics. I have it taped off with the first layer of paint on it after I primed it. Life has just slowed down the finish of the project. I hope to finish painting it this weekend.
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Mr.Tallahassee
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Sun Jul 29, 2012 1:39 am

I just found a potential problem with the linked QEV. The valve is rated for 0-0.8kgf/cm^2. That's roughly an 11.4 PSI rating. I don't know that using that is such a good idea.

EDIT: Nevermind. I missed the stateside post and the QEV from Grainger. I feel stoopit. :lol:
Sarcasm is the body's natural defense against stupid.
Petitlu wrote:My balls are made of lead and weigh 22g but I can make heavier or lighter ...
kb18951452
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Mon Jul 30, 2012 8:40 am

Wizard wrote:I used a female stabilizer from Palmers Pursuit to connect my HPA tank to my launcher and then used macroline to plum the air into the chamber. Its all rated for standard full pressure HPA tanks on paintball guns and the stabilizer lets me bring the PSI down to 100 where I wanted it.
So, it might be a trick getting the regulator and the bottle connection seperate (Because of where the bottle will be might be a trick making it adjustable ...)

I'm buessing a stabilizer is a threaded input for bottle, and a holster?
kb18951452
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Mon Jul 30, 2012 12:30 pm

3-way solenoid -
http://www.grainger.com/Grainger/wwg/se ... sst=subset

3/4 QEV
http://www.grainger.com/Grainger/wwg/se ... sst=subset

Both from grainger.

Going to go get a few fittings and a sprinkler valve to make a prototype. I really wish i knew what size chamber i'll need. I'm guessing 2.5" diameter x 12" chamber will be siggicient for a 12" barrel

not exactly sure.
Wizard
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Mon Jul 30, 2012 2:36 pm

kb18951452 wrote:
Wizard wrote:I used a female stabilizer from Palmers Pursuit to connect my HPA tank to my launcher and then used macroline to plum the air into the chamber. Its all rated for standard full pressure HPA tanks on paintball guns and the stabilizer lets me bring the PSI down to 100 where I wanted it.
So, it might be a trick getting the regulator and the bottle connection seperate (Because of where the bottle will be might be a trick making it adjustable ...)

I'm buessing a stabilizer is a threaded input for bottle, and a holster?
This is what I used, I screw the air tank right into it and the output on it can be regulated from 0-200 psi via a set screw on the top end. The Output is on the side and I mounted it using one of their ring mounts with some other paintball parts right to the launcher for a more compact unit.
kb18951452
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Mon Jul 30, 2012 2:40 pm

wizard what kind pressure are you using, in how big of a chamber to fire?
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mattyzip77
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Mon Jul 30, 2012 6:17 pm

Kb they have those same qev's on e bay for half the price of grainger. Just tryin to save you a few bucks. Good luck!
Go Bruins!!!!
kb18951452
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Wed Aug 01, 2012 5:34 pm

just cobbled together a proto with a 14" long 3" diameter chamber, and a 10" long 3" diameter barrel. Using a 1" sprinkler solenoid valve. No pressure guage so i have no idea what kinf of PSI i am working with. 25 bike pump pumps :) doesn't go far. (Maybe 25-30 feet), plus i was shooting a polo (partial button up shirt) which is probably much heavier than a tshirt.

I'm getting honking, i am sure the problem is with my pilot being the solenoid valve instead of a spray gun as i see all over the place.

Am i thinkign in the right direction?
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mattyzip77
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Wed Aug 01, 2012 9:24 pm

How are you actuating the valve now??
Go Bruins!!!!
kb18951452
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Wed Aug 01, 2012 10:53 pm

3 9v batteries. I think that causing the honking. I need to use a blow gun, to pilot it faster.
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jackssmirkingrevenge
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Thu Aug 02, 2012 12:56 am

kb18951452 wrote:just cobbled together a proto with a 14" long 3" diameter chamber, and a 10" long 3" diameter barrel. Using a 1" sprinkler solenoid valve. No pressure guage so i have no idea what kinf of PSI i am working with. 25 bike pump pumps :) doesn't go far. (Maybe 25-30 feet), plus i was shooting a polo (partial button up shirt) which is probably much heavier than a tshirt.
Probably not more than 100 psi.
I'm getting honking, i am sure the problem is with my pilot being the solenoid valve instead of a spray gun as i see all over the place.

Am i thinking in the right direction?
Pretty much, increasing the size of the pilot valve is definitely the way to go, but you're probably also being let down by low pressure. Get yourself a cheap track pump that will go to 150 psi plus, they usually have a gauge on them too.
hectmarr wrote:You have to make many weapons, because this field is long and short life
kb18951452
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Fri Aug 03, 2012 2:20 pm

Working on my Model,. Trying to keep in mind the shape in the end. Does it matter "where" behind the projectile the air enters, so long as it enters behind the effect should be the same?

The reason i ask is because i'm having trouble figuring out how to make things fit and approach att he "right angles" to come in the back / end of pipes, etc.
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jackssmirkingrevenge
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Sat Aug 04, 2012 1:52 am

kb18951452 wrote:Working on my Model,. Trying to keep in mind the shape in the end. Does it matter "where" behind the projectile the air enters, so long as it enters behind the effect should be the same?
Technically if it's coming in at weird angles you create turbulence, which is bad for performance, but usually not enough to be noticeable. Flow matters though, you want the area though which the air is coming through to be as big as possible.
hectmarr wrote:You have to make many weapons, because this field is long and short life
kb18951452
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Sat Aug 04, 2012 9:26 am

As you can see in the picture i'm considering cocking the QEV at a 45 angle, to keep the inlets to the chamber and the barrel on the flat sides of the cylinder.

Was thinking 3/4 Male NPT on the QEV going to both pipes.

Then another at the Pilot port of the QEV to get the connection there to the rear of the gun where the reservoir will be located, and the 3 way solenoid.

The gun doesnt have to be this shape, but its got to look like an overwised "pirate pistol".

I considered placing the QEV inside the chamber, so the barrell screws directly to its port sticking out, but how to get the resivoir line to it was a tricky matter.

What thoughts. What i "want" is a QEV where the two opposite ports are the chamber and the barrel, and the "side" port is pilot.
Attachments
Mockup for planning of components.
Mockup for planning of components.
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jackssmirkingrevenge
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Sat Aug 04, 2012 4:53 pm

Have you considered making a preloaded cartridge?

Similar to this concept: http://www.goblinpaintball.com/

Image

Here's a possible design, grey parts are metal, purple parts are delrin or similar high strength polymer. Everything is epoxied in place. This means it is not serviceable if something goes wrong internally, but it's so simple that there's very little to go wrong.

By using existing tubing for the cartridge body and "barrel", you'll save a lot of work and money on materials.

By using a schrader a fill/pilot valve, you don't need to build a separate fill rig.

By using high pressure, you probably won't even need a rubber seal, the delrin/metal contact should be airtight as long as both surfaces are polished and true.

You can get a 600 psi shock pump for around 55 of your finest US dollars.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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