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A few Newbie questions

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: iknowmy3tables » Mon May 05, 2008 5:07 pm

buying schraders except the threaded ones which sometimes are nesseary is for suckaz you should be able to get those for free, just go to the dude who does your parents tires and if he's cool he'll give you free ruber schraders, remember to ask for "rubber Schrader valve stems" and that he knows you are a customer or associated with one cause this will increase your chances of getting them for free, or at least thats what I observed.

quick disconnects can be bought at your local hardware store with the pipe

a rough 1:1 chamber:barrel ratio will be fine, as long as the chammber isn't absurdly small you should be able to do a dozen paintballs fine, these things arn't so weak man

your HPA equiped with a regulator will work fine, your can get the fittings to attach a tire chuck to fill the chamber via shrader
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Unread postAuthor: darthturkey » Mon May 05, 2008 5:50 pm

Yea thanks at this point im throwin around a few ideas. Because I have a new PMR and the damn thing is an air sucker im thing the HPA tank is going to be a little over taxed. So im going to end up using the schrader valves and filling with a bike pump. But just on a future note once I do a little more research i'd like to look into making my own pump so I dont run threw them like crazy when the break. Thanks for all the help guys ill be making a run to Home Depot tomorrow to pick up some
primer
glue
LOTS OF PVC
if i can find a sprinkler valve
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Unread postAuthor: darthturkey » Mon May 05, 2008 7:13 pm

Also now im having some trouble convincing the parents about the fact that what im doing is safe and it will be done right. See a story somehow popped up about a person with shrapenel and explosion of piping. So I realize that the PVC I will be using will be rated to hundreds of PSI but do you guys know of anything else I can say to my parents to reassure them of the fact that this will not be dangerous.

EDIT: Sorry about the double post didnt realize.
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Unread postAuthor: iknowmy3tables » Tue May 06, 2008 11:00 am

uh we get that question a lot, uh hundreds not exactly, the deal with pvc is that in the case that it does burst it tends to shatter and air presure will make this violent, so the manufatuers say only use for water presure, but the risk of breaking is almost neglectable as long as your safe: no suden drops or bumps while presurized so be careful, don't over presurize for pvc we usally keep it under 125psi but don't leave it like that, of course safe material absolutly no celluar core pipe, rated sch40 or higher pipe and fittings don't use dwv stuff like reducing couplers elbows and tees with the curved shape for flow and shallow sockets I belive the sockets are supose to be about 2/3 or more in depth compared to the pipe's diameter
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Unread postAuthor: darthturkey » Wed May 07, 2008 9:54 pm

well my design now intails a well reducer well kinda expander it brings my ball valve from a 1.0 to a 1.5 into the air chamber. So what your saying is trash the reducer? Also for the schrader what is the exact name of the female end that I will attach to my air chamber?
Just to make the above question a little bit clearer my design is as follows: (I realize its only a ball valve but I dont want to get into sprinkler valves and more complicated stuff just yet so at this point i'll call it version 1.0) A 12 inch barrel followed by a ball valve, next I was going to do a reducer that goes from 1 inch to 1.5 inches (I will modify the design after reading iknowmy3tables warnings thanks) to a 1.5 inch tank that is 9 inchs long followed at the end by a 1.5 inch end cap. Connected to my last section of 1.5 inch piping will be a pressure gauge and a female connection of the schrader valve. Next I will create multiple 9 inch long 1.5inch diameter tubes with end caps on each side. Connected to this tubes will be both a pressure gauge and male end of a schrader valve. This "tanks" will be filled with a bike pump to a specific PSI (Pending on tests that will be performed earlier so that I can determine the lowest possible PSI needed so I can be safer and make the pumping job easier). This "Tanks" are then somewhat of the black powder if it were a musket.
Finally to fire the "tank" will be connected to the chamber via the schrader valve and then I will turn the ball valve. After that shot the "tank" will simply be replaced by another already charged one.

Now on another note would it be safe to fill say 2 "tanks" and connect one before play then during play use the first one then attach the second or should I keep the "tanks" charged with air for the shortest amount of time. If that is the case ill simply take away the tank idea and make the air chamber the only area to be pumped.

Sorry for the extremely long post but this being my first cannon and all I want it to work and make sure im being safe. Thanks guys.
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Unread postAuthor: Hydra » Thu May 08, 2008 5:17 am

During play time and in between games? Your not shooting this at people at 100psi are you?

The simplest and best way I CAN THINK OF is using 2 ball valves and a couple of threaded bushings.

The air tank has a ball valve on it, and connected to the ball valve is a Threaded male bushing.

Now the chamber has the exact same thing exept the bushing is female.

So you start with both BVs closed, connect the tank and chamber by screwing them together. now OPEN THE CHAMBER BALL VALVE FIRST. Then open the tank ball valve and air from the tank flows into the chamber. NOW CLOSE THE CHAMBER BALL VALVE FIRST. Then the chamber ball valve, unscrew and fire.
The reason for "capital letters" is because you dont want high pressure in the connecting bit for a long time. Sorry about no pic by the way, but try and picture it in your mind.

EDIT: How would you connect the chamber to the air tank with a schrader valve. You cant do it with a normal one.
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Unread postAuthor: darthturkey » Thu May 08, 2008 6:52 am

See thats what I was wondering. Now im not shooting at 100 PSI im going to contruct the cannon itself. After this I will start at 10 PSI and work up in increments of 10 PSI at a time. Each time firing 10 paintballs 1ft away from a NPP certified paintball mask. After I find the perfect PSI for speed but safety I will perform 20 shots all at 1 ft to assure myself it is safe and will not harm the person.
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Unread postAuthor: grumpy » Thu May 08, 2008 7:05 am

you should understand that that these cannot be shot at other players, and most fields only alow the nerf rockets to be used.
you should read these two threads, it is about two seperate cases where launhers exploded from not being regulated and safety popoff valves were not used.

http://forums.warpig.com/phpbb/viewtopic.php?t=22497

http://forum.specialopspaintball.com/in ... =0&start=0
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Unread postAuthor: darthturkey » Thu May 08, 2008 2:47 pm

well not to shoot down your safety warning but in both instances they were matching manufactured pbjects with homemade. In the first instance from the picture the man used an HPA paintball tank. These are manufactured to be used for paintball guns only. In this instance obviously he had not read the safety warning on the label on every HPA bottle which states " Improper use,filling,storage, or disposal may result in death or serious injury" The same problem was evident in the second case. The guy used 1 2 gram co2 catridge which he shouldnt of. And im not sure if he screwed up with words but he made a major mistake that probably caused his injury.
"i used pvc cement" he stated no use of primer which is needed to properly bond PVC piping. So both times it was simply a lack of safey precaution and poor plannijng which lead to their problems. I have no intention whatsoever to attach a HPA or co2 catridge to anything I make. In my mind it is irrisponsible to attach a tank pressurized at 3000 - 4500 PSI. Secondly that guy used no reg. He simply and i quote "Opened his ASA for 1/2 a second" In my personal opinion that guy made a very poorly planned cannon and made some major safety breaks.

I will be using a bike pump and when charged to 40 PSI the air chamber would be no more pressurized then a bike tire. Furthermore this is a homemade field.


So to put it simply both attempts were poorly planned out and had no real backing safety wise. That is why i choose to stop off at this site and have my plans looked over before I went of gung-ho gluing piping together.
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Unread postAuthor: darthturkey » Thu May 08, 2008 7:45 pm

I've been doing a little bit of reading and poking around and would it be better and safer for me to use copper piping? From what I've read so far it has better tolerances to compressed air as well as it not turning into a fragmentation grenade when pressurized. Also I took a run down to my hardware store and looked around and there was some very heavy metal piping fittings, are these rated for compressed air and if so are they an even beter choice? I only ask and think about changing my design because at this stage I'd like to make a lasting gun and also from what I've read and so far concluded is with the more times the PVC is used the more prone it is to becoming a safety hazard. If I do switch over to copper or those heavy duty pipes would I just sceew them in whilst wrapping the threads with teflon tape? So just a little light on the matter would be helpful.
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