New hybrid cannon

[sw5amped]

I finally was able to complete my latest build yesterday. This is a basic, run of the mill, hybrid cannon. It has a 48" chamber, propane meter pipe is 1" in volume with a quick connector. The Schrader valve stem is in the center of the chamber and is teed along with a 200 psi gauge. There is also another 200 psi gauge behind the ball valve that separates the meter pipe from the chamber. I only about it at a3x mix but it has much potential!!! Any feedback would be great.

[jackssmirkingrevenge]

Let's see it in action

[sw5amped]

Ahhh!! I like ur style! I'm picking up a compressor tonight. The one i used i borrowed from a friend. So ill post a vid of something getting blown up!!!! Shooting this hybrid reminds me of shooting a 410 shotgun!!! Tooo much fun!!!

[sw5amped]

I was wondering if someone wouldn't mind checking my fuel mix ratios. My chamber is 45 ci. At a 2x mix i add 36 psi of propane and 15 air. At a 3x mix i add 54 propane and 30 air. I just bought a compressor last night and was able to do some test firing. The gun shot great at 2 and 3x mixes. I attempted to load up a 4x mix and my Schrader valve froze open. It is under 10 degrees where i live. I'm changing that Schrader out today with a ball valve and quick connect so i won't be having that issue any more. Oh my mix numbers for 4x were 72 propane and 45 air.
Any feedback would be great. I'm going to record some vids today while i have the daylight. Oh and also I'm using a 3/8 dia meter pipe that has a vol. Of 1.2 ci

[jackssmirkingrevenge]

I got 95 psi absolute of propane for 4x, 80 psi if the propane gauge reads zero at atmospheric pressure. How did you calculate it?

[sw5amped]

Yo jackss!! Let me start off by thanking u for the help here.
I did that test fire session and had some problems. So i did a fluid volume check and come to find out i was off quite a bit on my chamber size. I was using 737ml but in truth the chamber is 812ml. So i redid my math and came up with 2ci or 34ml of prop needed to be in chamber for normal combustion. So from there i just multiply by mix #. So let's say i wanted to spin up a 3x mix i would multiply 2x3 to get 6 then divide 6 by 1.389 (which is the vol of my meter pipe) to get 4.2 then i multiply by 14.7 to get 63psi of propane and for the air i filled chamber to 3bar. So i did another test fire last night and i set the gun up to exactly for a 3x mix and boom!!!!! It shot excellent!!! Im really hoping that im correct with my numbers. Any advice u have would be great. I got 84 prop for 4x mix. Im posting the latest pics of the updated gun.

[jackssmirkingrevenge]

Yo jackss!! Let me start off by thanking u for the help here.

That's what this forum is for

I did that test fire session and had some problems. So i did a fluid volume check and come to find out i was off quite a bit on my chamber size. I was using 737ml but in truth the chamber is 812ml. So i redid my math and came up with 2ci or 34ml of prop needed to be in chamber for normal combustion.

You should include the volume of the meter pipe in the calculation as well, other than the math looks OK. This looks like it will do some nice damage, looking forward to it!

[Jose Arcadio Buendia]

Is that a PVC union in the breech?

[sw5amped]

Yes sir it is. Its rated for 175psi. I was using it for 4x mixes and under. Works f...ing great!!!! Im literally walking in my apartment coming from a test fire session. Im absolutely thrilled at the way this gun fires!!!! Only problem is....the spuds come out as a mist after 3x mix. I gotta machine me up some rounds!!! Roughly 13mm. I must say that i pulled my hair out for many o nights trying to get the correct fueling for this hybrid and finally i got the numbers worked out perfect i can sleep at ease......or until the next build!!! Lol!

[noname]

I'd advise swapping out the union for a metal one as soon as possible, PVC is gonna blow shrapnel everywhere when it fails. I think the general rule for hybrids is to assume 80-100 psi per mix, so you should be hitting well over 300 psi. Along with the fact that it's a pressure spike rather than slowly building it up, that PVC union is just a failure waiting to happen.
It's unfortunate but trusting that, especially as a handheld, is really risky.

[PeteS]

I really like the design of the PVC unions, but wouldn't trust them on a hybrid. Too bad they don't make an aluminum one that uses a similar design.

Cam lock fittings are another option. The pressure ratings aren't too high, but I trust them well above their rated pressure while I don't trust PVC at it's rated pressure. PVC is just too inclined to shatter. I have had some issues with some cam locks not gripping some burst disk materials well enough.

[sw5amped]

I'm loving all the feedback I really appreciate it. the deal with the PDC Union is because it has an o ring in it and I couldn't get my 1 inch steel Union to seal. but listen I'm going to lose that PVC union asap!!! I actually only had it on the gun to test fire it without any rounds in it I guess I got carried away. Can I modify the steel Union I have to make a better seal it has a lip on it that doesn't seem to make a seal correctly. Oh by the way it is 1". I'm at work right now but ill post a pic of the union when i get home later.

[jackssmirkingrevenge]

We really need to see this thing ventilating some targets

[sw5amped]

Hear that bro!!! Every day i get home from work it's already dark, but i gotta few spots picked out. Ok done deal. Tonight the camera will be rolling!! Till then ...

[noname]

Steel unions as they come from the store won't seal by themselves. I always head over to the gasket/O-ring section of the hardware store, disassemble the union, and find a gasket that's the right size to seal it up. If you can't find one, it's pretty easy to get sheet rubber and cut a little ring. You can just pop the gasket in right where the O=ring is in the PVC union and it should work fine.
Good luck!