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Project: 10 gallon

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Unread postAuthor: mobile chernobyl » Tue Jul 29, 2008 12:59 pm

- Especially when 10' + Barrels are thrown into the mix.

Okay Nix the 1.5" porting "QEV" I've prolly got better idea's spend the money on.

Tonight I'm gonna try and assemble the "X" Valve portion, and the tanks (Perhaps the 90's as well). I'm not gonna glue the "X" Valve to the tanks until these two items are assemble so I can have the barrel sit perfectly level.
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Unread postAuthor: jonnyboy » Tue Jul 29, 2008 1:17 pm

I looked on savko.com but I couldn't find the regular pvc parts where are they?


EDIT-wrong web address
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Last edited by jonnyboy on Tue Jul 29, 2008 3:06 pm, edited 1 time in total.
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Unread postAuthor: mobile chernobyl » Tue Jul 29, 2008 2:48 pm

First you checked Savko.com right? Savco.com is like some pest control service in Australia :shock:

It's (Select Product Grouping):
->Fittings
->PVC Schedule (whatever you want) Fittings
->Then click the lower "View" button to the right of the drop down menu.
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Unread postAuthor: jonnyboy » Tue Jul 29, 2008 3:11 pm

Thanks man I was looking at the quick links instead.Prices are decent too. My next cannons can be built without leaving my home.
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Unread postAuthor: mobile chernobyl » Tue Jul 29, 2008 7:20 pm

Scary isn't it? haha. Lowes carries LASCO NSF-pw fittings up to 2" as well. Thats where I bought everything for "1 gallon". I will be ONLY using pressure rated fittings where it matters now haha. My juviniele days are over if I can help it, Just glad to have lived through them :shock:
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Unread postAuthor: blind909 » Wed Oct 08, 2008 10:10 pm

Sorry to kick up the topic, but how is process going?
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Unread postAuthor: starman » Wed Oct 08, 2008 10:19 pm

Maybe you should shoot him a quick PM. I haven't noticed mobile posting much lately.
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Unread postAuthor: kiwi of nitro » Thu Oct 09, 2008 11:53 pm

Maybe he got blown up, by his NMO pipe. :idea:
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Unread postAuthor: mobile chernobyl » Thu Nov 06, 2008 1:42 pm

Nope didn't get blown up by my pressure rated pipes and fittings :roll:

In fact they're still sitting in my house back at home. I ended up going away for college this semester, so I really haven't had any time to even think about building this. It's hard when all the parts are there and just begging to be assembled haha, but I really need to study hard this semester for my major (Mech eng, minor Chem).

I'll post an update on this either by christmas break or next year spring time. Christmas break would be ok to assemble it, but I would not feel comfortable bringing it outside in 30 degree temperature and comfortable pressurizing it to 80psi, and then firing and repeating it all numerous times.

In the mean time at college I have begun to refocus on a more refined version of our spudguns, paintball haha. Since I can at least play paintball here, I spend some time on solidworks everyonce in a while when I get a cool idea.

Here's a few I've developed since I last posted on Spudfiles.

Image

Image

Image

The desceptive eye will notice that these are not spudguns (joke intended). What you may notice is that the first one uses "spudgun technology". Thanks spudfiles for opening my eyes to new pnuematic valves lol. The rest are spool valves, somethign I was trying to bring to spudgunning with my semi-auto project that most likely won't be produced. It would be very inneficient compared to my newly aquired poppet valve knowledge from working with some great paintball people in the industry over at PBnation.com .

Well just checking in, if anyone has any other questions send a PM cause then I'll at least get a notification by e-mail, otherwise I prolly won't be posting again till december - School's my new priority lol.
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Unread postAuthor: john bunsenburner » Thu Nov 06, 2008 2:44 pm

You remind me of myself right now!!! im a mad 13year old gunner :twisted: , maybe u can help me out sometime, that is if i need help... Right now i am building an air powered, realistic, semiauto sniper rifle
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Unread postAuthor: mobile chernobyl » Wed May 27, 2009 10:46 pm

Well I told you I'd Make this by spring and I lied. sorry lol

I had to end up waiting until summer. 10 gallon has turned into 11 gallon + now and has taken shape to be quite a large cannon.

Image
Image
Image
Image

It was fab'd and glued about 24 hrs ago, still need to fab a stand for it with elevation control.

I'm glad I decided to put this on hold as I wasn't going to be able to use it until June anyhow, and I was able to concentrate on my schoolings rather than PVC creations. I ended up getting straight A's and Deans list status last semester so I'd say "holding off" paid off. Remember kiddies u can always make a gun, but you can't always retake a test for a $3000 college class because you wasted your time making a budget air gun.

I was also able to strike up an internship this summer, and a hell of a good one for anyone looking to make spud guns (or get experience to make the "big one")...

I got into a company that makes custom water purifcation units for power plants around the world, and I got hired because of my Tig welding skills. Currently I weld ALOT of 3" sch 10 stainless pipe and fittings that are going to be subjected to 300PSI of water pressure. Needless to say I've got my welding skills down pretty good and will eventually (hopefully) work on making a high pressure coaxial from some of the 3" pipe and other smaller scraps if I can.

I need some idea's for what style stand to make for this monster I currently am in the process of making however - I know there are alot of military buffs on here, if you could find me some info on larger caliber cannons with elevation control and dampening on the stand side, as well as wheeled portability (I'm thinking something like a howitzer) I would appreciate it. I found a scissor jack that can lift 2000lbs at a yard sale so that should be adequate for elevation control, but I want pic's of howitzers if anyone knows of a cool design out there post it!

Also one quick question for the knowledgable few on here - What is the agreed upon distance a piston must open (or travel rearward) in relation to the porting diameter outlet? I have a 3" sch 40 sealing face, so that gives the porting diameter (3" porting piston). I seem to remember someone saying DiamterOfPort/4 , but I also remember that being the formula for a coaxial, which this is a little different from. Right now I have 2" of travel accomadated for, but with that a lot of force will be generated by the piston and a really good bumper will need to be used. I'm wondering if I can get away with say... 1.5" and not lose any performance air dumping wise. the less force the piston creates the safer this monster will be.

Thanks for any help and I'll try and keep this updated with progress of the stand, pressurizing system, and initiating system.
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Unread postAuthor: Technician1002 » Wed May 27, 2009 10:59 pm

mobile chernobyl wrote:
Also one quick question for the knowledgable few on here - What is the agreed upon distance a piston must open (or travel rearward) in relation to the porting diameter outlet? I have a 3" sch 40 sealing face, so that gives the porting diameter (3" porting piston). I seem to remember someone saying DiamterOfPort/4 , but I also remember that being the formula for a coaxial, which this is a little different from. Right now I have 2" of travel accomadated for, but with that a lot of force will be generated by the piston and a really good bumper will need to be used. I'm wondering if I can get away with say... 1.5" and not lose any performance air dumping wise. the less force the piston creates the safer this monster will be.


Generally 1/4 the diameter is the minimum. It's a fantastic build. For speed, use a lightweight piston. HDPE and UHMWHDPE are popular. To some extent wood has been used.
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Unread postAuthor: mobile chernobyl » Wed May 27, 2009 11:22 pm

Piston material will be OTC parts only, that's been a goal of mine for this launcher and the other "1 gallon" launcher.

That's not to say they won't be modified, but they will be OTC Sch 40 parts.

I'll do this mathematically instead of random he-said equations.

Area of porting hole = PI * (Radius of porting hole, or diameter/2)
Area = PI * (3.0625/2)
Area = 7.367 sq inches.

So I want that same area from the "gap" formed by the piston opening, in order to not "bottleneck" it.

Area of "gap" created by piston = PI * (Diamter or porting area) * (Distance piston moved back)

But we already know the area we WANT, so lets figure out the distance it must open to equal that...

Area, or 7.367 sq in = PI * PortDia * PistonDist

Area / (PI * PortDia) = Distance

7.367 / (PI * 3.0625) = .77"

OK so it basically is Dia/4, but I proved it so I'm a little more confident now lol.

I'll prolly still go with 1.25" that gives me alot more confidence I can make a simple bumper to dissapate the force and not blow the back out when firing fletched 20oz coke bottles filled with cement and tipped with "metal penetrating tips" tee hee hee.
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Unread postAuthor: Technician1002 » Wed May 27, 2009 11:42 pm

mobile chernobyl wrote:Piston material will be OTC parts only, that's been a goal of mine for this launcher and the other "1 gallon" launcher.

That's not to say they won't be modified, but they will be OTC Sch 40 parts.


Suit your self. I moved away from PVC pistons due to the very high failure rate. At first I thought it was from impact, but later found the high failure was from repeated stress causing crazing. The attached photo is the 4th piston my 1 inch coaxial broke. The piston is a 1 inch pipe cap sanded smooth. 3 of the 4 broke a hole right in the center of the face of the piston where it impacts nothing. This last one cracked from the EQ hole in the side, again a location away from any impact stress. I replaced it with HDPE.

I have never had a HDPE piston fail.
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Attachments
BrokenOriginal.JPG
Cracked original Mouse Musket piston.
PICT251.JPG
Drilling the EQ port on the replacement piston.
Musket.jpg
The mouse musket. 1 inch barrel coaxial in a 2 inch chamber. The hole in the plywood was made by a gumball fired from this cannon.
Last edited by Technician1002 on Wed May 27, 2009 11:52 pm, edited 1 time in total.
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Unread postAuthor: mobile chernobyl » Wed May 27, 2009 11:48 pm

What type of bumper are you using? I've put alot more stress on that in my designs after a faulty bumper design caused a catastrophic failure on a 4" coaxal I had allowing the piston to shoot out the back of the gun.

The piston design I will be using is good amount different from your's however and I'm not too worried about cracking. I'll post a pic of it when completed.
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