A few progress pictures of my handheld. the CPH

Harness the power of precision mixtures of pressurized flammable vapor. Safety first! These are advanced potato guns - not for the beginner.
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Jeeperforlife
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Thu Apr 10, 2008 9:22 am

My handheld is a coaxal piston valved hybrid. Nicknamed CPH for short.
The tee that you see will have a shrader valve on the bottom for filling and a port for two wires for the ignition. The method of firing the gun is to use compressed air behind the piston to seal it aginst the barrel. when the piston moves back it will slide the tube back exposing holes in it to let out the air to allow the full power of the shot to go out the barrel.

there is still a lot of work to do to get it ready to fire. Here is the pictures.

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starman
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Thu Apr 10, 2008 9:42 am

I'm having a little trouble following your setup and fire plan, it's probably me being dense this morning... :wink: What is going to cause the piston to unseat upon firing? Is your piston going to be sealed from front to back? How is the small pipe on the piston being used.

Maybe a quick drawing would help.
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psycix
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Thu Apr 10, 2008 10:00 am

Looks nice jeeper! Cant wait til its finished!
Keep us updated with the pics.
Oh, and I would like to see the internals.
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Lentamentalisk
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Thu Apr 10, 2008 10:01 am

Its your standard piston cannon, but filled with propane and air instead of air, so that when you ignite the fuel, the pressure increases, knocks back the piston, and flies out the barrel.
Really cleanly done from what I can see.
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Jeeperforlife
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Thu Apr 10, 2008 10:12 am

Lentamentalisk wrote:Its your standard piston cannon, but filled with propane and air instead of air, so that when you ignite the fuel, the pressure increases, knocks back the piston, and flies out the barrel.
Really cleanly done from what I can see.
You are right.

Thanks for the comments.

There is not really much to show inside yet, but when I get the insides welded in I will post up.

The pipe on the back of the piston goes through the back of the cap. The pipe will have 2 holes at the bottom and 2 holes just inside the sealing surface on the end cap. I would do a drawing but I suck at it so for now you will have to use your amagination. The piston will be getting 3 Orings to completely seal on the chamber.

Edited for clarity.
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SpudFarm
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Thu Apr 10, 2008 3:02 pm

NICE!!!

that is so fuc£!ng nice!

hurry up! want to look at this done ;) ;)
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JDP12
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Thu Apr 10, 2008 3:23 pm

wow very nice! good job, can't wait to see it in action
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Jeeperforlife
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Thu Apr 10, 2008 10:30 pm

spudfarm wrote:NICE!!!

that is so fuc£!ng nice!

hurry up! want to look at this done ;) ;)
I am curious if the winking smiley is directed to the fact that I have yet to finish a gun I started since joined the site. hmm come to think about it I have been working on the other project to much lately.

OK I promise to my self to finish this as a hybrid and make the 3000PSI pressure amplifier wait. I am building it as a duel purpose gun, hybrid and high pressure pneumatic with just a change out of piston and caps. Thanks for the incouragement to keep working on this.
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Lentamentalisk
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Thu Apr 10, 2008 10:42 pm

Jeeperforlife wrote:I am building it as a duel purpose gun, hybrid and high pressure pneumatic with just a change out of piston and caps. Thanks for the encouragement to keep working on this.
Why do you need to change the piston? What is the difference between your pneumatic and hybrid pistons?
Also, couldn't you just leave the hybrid cap in? I think that you could probably pretty easily make it so that no change is necessary what so ever.
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Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
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JDP12
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Fri Apr 11, 2008 7:18 am

Yea, i agree with Lentamentalisk
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Jeeperforlife
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Fri Apr 11, 2008 10:05 am

Lentamentalisk wrote:
Jeeperforlife wrote:I am building it as a duel purpose gun, hybrid and high pressure pneumatic with just a change out of piston and caps. Thanks for the encouragement to keep working on this.
Why do you need to change the piston? What is the difference between your pneumatic and hybrid pistons?
Also, couldn't you just leave the hybrid cap in? I think that you could probably pretty easily make it so that no change is necessary what so ever.
Mabe I don't plan to use a piston at all on the pneumatic. Not to spoil the fun but I was planning a valveless design with a blow gun trigger to fire it. That way I don't have a piston destroying itself at 3000psi and better performance with no valve opening time. Any valve built to withstand that would be too heavy.
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Jeeperforlife
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Tue Apr 22, 2008 10:07 pm

Sorry but this is going on the back burner for the moment. I got the piston done and the end cap done with seals and stuff, But the weather is nice here and I am getting started on my son's gocart. My wife is also expecting a new lift on her Jeep so I will be very busy. I will drop by almost every day but will only post rarely. I am going to start a thread soon on the general forum for the ideas and projects I have been working on. I guarantee I will pick up the projects and hobby again latter.

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MrCrowley
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Tue Apr 22, 2008 10:22 pm

Jeeperforlife wrote:I guarantee I will pick up the projects and hobby again latter.
You couldn't drop this hobby if you tried :wink:

Looking good so far, i'll be eagerly awaiting the completed product :)
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