Super Soaker Central forums

DX · 08-14-2006, 11:39 PM

The piston probably isn't that hard to put together, Ben did post pics of it somewhere. Found them:

Nevermind, the pictures were WAY too big to put here.
http://www.sscentral.org/images/supercannon/

My only question for a piston water cannon is whether or not a pressure release valve is needed to get the pressurized air out after all the water is used up, and if so, where to get one and what kind/size.

Silence · 08-15-2006, 09:16 AM

In theory, I don't think a pressure release valve would even work. If you want the pressure to be high enough for it not to activate when the piston is far back, then once the piston has moved forward, the pressure will be lower still. And anyway, unless it's set to 15 PSI, it's not going to help--and at 15 PSI, it will always release all excess pressure.

I believe Ben just released the air using some type of valve configuration--extremely easy if you use a Schrader valve as I'll expect you'll do. From what I know, pressing down on the pin or whatever on the Schrader valve will release all the air, although it might be fairly slow. My suggestion is to add a PVC ball valve at the other end to safely and quickly let out all the pressure.

I'm more certain that Ben used a ramrod to push the piston back when refilling, and that obviously happens after you get the excess pressure out of the PC.

EDIT: Those are indeed pictures of the seal Ben used, but I'm trying to find wherever he stated what McMaster-Carr part number it was. I'm sure Duxburian recorded it, though...

CROC · 08-15-2006, 10:50 AM

When I asked how it was made, I was referring to the larger parts of the piston that hold the pressure. What are they made of?

DX · 08-15-2006, 01:22 PM

Quote:

I believe Ben just released the air using some type of valve configuration--extremely easy if you use a Schrader valve as I'll expect you'll do. From what I know, pressing down on the pin or whatever on the Schrader valve will release all the air, although it might be fairly slow. My suggestion is to add a PVC ball valve at the other end to safely and quickly let out all the pressure.

Wow, I should have thought of something as obvious as a ball valve. It would be interesting to add a barrel to the valve, and turn the end of the water cannon into a water balloon launcher so you could use that air. Then again, it would make the gun rather ugly.

The part number is 9411K28.

Silence · 08-15-2006, 01:35 PM

@ CROC: Those are pretty much just rubber "piston cups"--or at least, that's what McMaster-Carr calls them. Go to their site and search for the part number that Duxburian conveniently provided and you'll see the finer details. So in answer to your question, they're made from Buna-N rubber, which I think is a bit more resilient than latex rubber.

@ Duxburian: If you dare to search my various posts, you'll find that a few months ago I proposed something a bit like what you're saying. It was pretty much a shoulder-mounted rocket launcher type of thing, but the idea is clearly too impractical to work. I get the feeling you were joking, at least to some degree...

And thanks for finding the part number.

DX · 08-15-2006, 04:44 PM

I was actually somewhat serious. Just releasing the air seems like a waste. After unleashing the fury of the water cannon, why not cap it off with a long range surprise? While a water cannon with a launcher barrel on the back would be interesting, it would probably be too long to be practical to use in battle.

Silence · 08-15-2006, 06:05 PM

If anything, its impracticality is not due to its length. The problem is that the energy you put into pumping is already (mostly) used by the movement of the plunger. That is to say, if you start off with 150 PSI and the volume of the air chamber increases by 6 times when the piston moves, then you'll only end up with 25 PSI.

Perhaps the increased volume of air will help, but I think at that level you would need more pressure to achieve desireable performance. I'm probably wrong, but it's something to think about.

Ben · 08-19-2006, 08:28 PM

After a 100 PSI shot, there's still 40 PSI of pressure left in the chamber. So yes, you can use that air to power something. I was considering a small water balloon launcher attachment that also could be attached to the air output of SuperCAP. There's still a lot of air in there obviously. Ideally it will be used. I'm just not really quite sure how to use it.

Of course, that's with the piston in the center. I haven't tried too many other combinations. With the piston near the end, you will have a much greater pressure drop and it probably won't be worth using.

The air release valve actually is quite violent and has recoil of it's own. Very loud. I've considered a special air nozzle to release the air slower and reduce the sound level.

I would also highly suggest against schrader valves with this unless you thread the valve onto a metal coupler. I never trusted using a thread tap under pressure. The threads on NPT threads are tapered to make a seal. A thread tap does not taper. Thus, you will get leaks. Just use an air coupler or thread the schrader valve onto a metal coupler.

Another interesting thing is the fact that with the release valve closed, you can build pressure just by hammering the piston down. It's got such a good seal that it will hold in place at pressures below something like 20 PSI unless it has some momentum. I noticed this by accident, and I've considered using it to reduce air consumption.

The piston cups also reportedly take 3000 PSI, so the PVC will break before the pistons will. Good investment as far as I'm concerned.

Ben · 08-21-2006, 12:49 PM

Drenchenator and I will be looking at the air exhaust feature today to test how loud it is. We have a sound level meter and we're hoping to see how loud the air exhaust is. If it is 80 dBs or higher, we'll install a pneumatic muffler to reduce the noise to about 20 dBs lower.

Right now I'm going to test a basic muffler I built to see how well it works.

Edit:

The air exhaust alone is about 105 dBs.

With the cheap homemade muffler I made, that's reduced to about 90 dBs.

I'll be finishing a more advanced muffler that would reduce even more of the noise today. I'll let everyone know how it turns out.

Silence · 08-21-2006, 05:12 PM

I think I might have missed hearing about how the air is released. Could you explain what valve you use again? Thanks.

That is pretty loud, though. Would you consider a ball valve in part of the gun in the future?

Ben · 08-21-2006, 05:42 PM

Check out the pictures (again, I apologize for the enormous size). The air release is an old slightly damage ball valve that's perfect for this. The damage was external and allows the ball valve to rotate in any direction. I figured it would be ideal for this because in an emergency situation, time is critical and with a valve that can be turned in any direction it's that much faster.

To clear this up to a few people who don't know: I don't use a schrader valve and never have used schrader valves. I've only used air couplers because we have so many automotive tools lying around it would actually be a waste of time to switch. That and air couplers have a better seal and are easier to work with.

I've been busy working on getting a new website design preview made among other projects (you know...), so I haven't taken any pictures of the current muffler I have made. The current muffler is a very basic one that only absorbs the sound with some fiberglass insulation I had. I'm going to make a second one to use in conjunction with this that will have a cancelling effect (read HowStuffWorks for where I got my designs from). I'm also considering making a second, longer absorbtion muffler.

The sound lasts a fraction of a second but still is extremely loud. In a water fight, this will give away your position. Ideally you'll use the air for something else. This is just another good reason to.

Silence · 08-22-2006, 08:40 PM

If using this in a water fight, you'd need a system for pressurization anyway--not that you haven't thought of that.

Perhaps if there was a hose leading to an air coupler on a WBL--that would be more flexible and allow for more practicality. On the other hand, a huge WBL barrel on top (or underneath, for that matter) of the weapon might act as a muffler in itself to some extent, especially if you put a flow restrictor (for lack of a better term) on the muzzle when not firing a water balloon.

CplPunishment · 11-25-2007, 02:09 AM

That
Was
Awesome.

I would looooove to know the mechanics of this water gun, because I'm not completely sure what kind of system you used. Nice work guys.

Silence · 11-25-2007, 06:08 PM

Take a look at this thread.

Basically, there's a large tube with a plunger in the middle that separates the tube into two chambers. Water enters the front chamber through the nozzle, then the rear is pressurized by a pump via an air coupling. It may be hard to see the coupling in the pictures. The valve is opened and the air pushes the plunger and the water forward.

Ben · 11-26-2007, 08:38 PM

Hey CplPunishment! I added you as a friend on Facebook.

Supercannon II is a pretty simple water gun. SilentGuy described it well. If you want some more detailed pictures or explanations, let me know. Right now I'm working on a site update that'll include a lot of things like how to construct this water gun. Getting really high performance isn't hard at all.

08-14-2006, 11:39 PM	#16
DX Wicked Super Admin Join Date: Feb 2004 Location: Easton / New London, CT Posts: 1,576 UserID: 75	The piston probably isn't that hard to put together, Ben did post pics of it somewhere. Found them: Nevermind, the pictures were WAY too big to put here. http://www.sscentral.org/images/supercannon/ My only question for a piston water cannon is whether or not a pressure release valve is needed to get the pressurized air out after all the water is used up, and if so, where to get one and what kind/size. __________________ Mess With the Best, Get Soaked Like the Rest!! 2004 Red Sox - World Series Champions 2007 RED SOX - WORLD SERIES CHAMPIONS! 2003 Patriots - Super Bowl Champions 2004 Patriots - Super Bowl Champions 2007 Patriots - God Damnit! If I change my sig, will the world end? Last edited by DX : 08-15-2006 at 12:00 AM.

08-15-2006, 09:16 AM	#17
Silence Administrator Join Date: Apr 2006 Location: Virginia Posts: 3,293 UserID: 576	In theory, I don't think a pressure release valve would even work. If you want the pressure to be high enough for it not to activate when the piston is far back, then once the piston has moved forward, the pressure will be lower still. And anyway, unless it's set to 15 PSI, it's not going to help--and at 15 PSI, it will always release all excess pressure. I believe Ben just released the air using some type of valve configuration--extremely easy if you use a Schrader valve as I'll expect you'll do. From what I know, pressing down on the pin or whatever on the Schrader valve will release all the air, although it might be fairly slow. My suggestion is to add a PVC ball valve at the other end to safely and quickly let out all the pressure. I'm more certain that Ben used a ramrod to push the piston back when refilling, and that obviously happens after you get the excess pressure out of the PC. EDIT: Those are indeed pictures of the seal Ben used, but I'm trying to find wherever he stated what McMaster-Carr part number it was. I'm sure Duxburian recorded it, though... __________________ Forum rules

08-15-2006, 10:50 AM	#18
CROC Senior Member Join Date: Mar 2006 Location: Ontario, Canada (GTA) Posts: 291 UserID: 569	When I asked how it was made, I was referring to the larger parts of the piston that hold the pressure. What are they made of? __________________ ~CROC~(c 'rock)n. -The master of ideas, and the occasional mod (Works with mr. dude) Mods: 3xA combat - CPS Turbine - Super Flash Flood - (working on CPH)

08-15-2006, 01:35 PM	#20
Silence Administrator Join Date: Apr 2006 Location: Virginia Posts: 3,293 UserID: 576	@ CROC: Those are pretty much just rubber "piston cups"--or at least, that's what McMaster-Carr calls them. Go to their site and search for the part number that Duxburian conveniently provided and you'll see the finer details. So in answer to your question, they're made from Buna-N rubber, which I think is a bit more resilient than latex rubber. @ Duxburian: If you dare to search my various posts, you'll find that a few months ago I proposed something a bit like what you're saying. It was pretty much a shoulder-mounted rocket launcher type of thing, but the idea is clearly too impractical to work. I get the feeling you were joking, at least to some degree... And thanks for finding the part number. __________________ Forum rules

08-15-2006, 04:44 PM	#21
DX Wicked Super Admin Join Date: Feb 2004 Location: Easton / New London, CT Posts: 1,576 UserID: 75	I was actually somewhat serious. Just releasing the air seems like a waste. After unleashing the fury of the water cannon, why not cap it off with a long range surprise? While a water cannon with a launcher barrel on the back would be interesting, it would probably be too long to be practical to use in battle. __________________ Mess With the Best, Get Soaked Like the Rest!! 2004 Red Sox - World Series Champions 2007 RED SOX - WORLD SERIES CHAMPIONS! 2003 Patriots - Super Bowl Champions 2004 Patriots - Super Bowl Champions 2007 Patriots - God Damnit! If I change my sig, will the world end?

08-15-2006, 06:05 PM	#22
Silence Administrator Join Date: Apr 2006 Location: Virginia Posts: 3,293 UserID: 576	If anything, its impracticality is not due to its length. The problem is that the energy you put into pumping is already (mostly) used by the movement of the plunger. That is to say, if you start off with 150 PSI and the volume of the air chamber increases by 6 times when the piston moves, then you'll only end up with 25 PSI. Perhaps the increased volume of air will help, but I think at that level you would need more pressure to achieve desireable performance. I'm probably wrong, but it's something to think about. __________________ Forum rules

08-19-2006, 08:28 PM	#23
Ben Founder Join Date: Mar 2003 Location: College Park, Maryland Posts: 6,054 UserID: 1	After a 100 PSI shot, there's still 40 PSI of pressure left in the chamber. So yes, you can use that air to power something. I was considering a small water balloon launcher attachment that also could be attached to the air output of SuperCAP. There's still a lot of air in there obviously. Ideally it will be used. I'm just not really quite sure how to use it. Of course, that's with the piston in the center. I haven't tried too many other combinations. With the piston near the end, you will have a much greater pressure drop and it probably won't be worth using. The air release valve actually is quite violent and has recoil of it's own. Very loud. I've considered a special air nozzle to release the air slower and reduce the sound level. I would also highly suggest against schrader valves with this unless you thread the valve onto a metal coupler. I never trusted using a thread tap under pressure. The threads on NPT threads are tapered to make a seal. A thread tap does not taper. Thus, you will get leaks. Just use an air coupler or thread the schrader valve onto a metal coupler. Another interesting thing is the fact that with the release valve closed, you can build pressure just by hammering the piston down. It's got such a good seal that it will hold in place at pressures below something like 20 PSI unless it has some momentum. I noticed this by accident, and I've considered using it to reduce air consumption. The piston cups also reportedly take 3000 PSI, so the PVC will break before the pistons will. Good investment as far as I'm concerned. __________________ email: / Forum rules / Read this page before emailing me. Do not send me a PM or email with a water gun question if someone else could answer the question. Post at the forums. You will get a response from me along with others' views or ideas.

08-21-2006, 12:49 PM	#24
Ben Founder Join Date: Mar 2003 Location: College Park, Maryland Posts: 6,054 UserID: 1	Drenchenator and I will be looking at the air exhaust feature today to test how loud it is. We have a sound level meter and we're hoping to see how loud the air exhaust is. If it is 80 dBs or higher, we'll install a pneumatic muffler to reduce the noise to about 20 dBs lower. Right now I'm going to test a basic muffler I built to see how well it works. Edit: The air exhaust alone is about 105 dBs. With the cheap homemade muffler I made, that's reduced to about 90 dBs. I'll be finishing a more advanced muffler that would reduce even more of the noise today. I'll let everyone know how it turns out. __________________ email: / Forum rules / Read this page before emailing me. Do not send me a PM or email with a water gun question if someone else could answer the question. Post at the forums. You will get a response from me along with others' views or ideas. Last edited by Ben : 08-21-2006 at 01:28 PM.

08-21-2006, 05:12 PM	#25
Silence Administrator Join Date: Apr 2006 Location: Virginia Posts: 3,293 UserID: 576	I think I might have missed hearing about how the air is released. Could you explain what valve you use again? Thanks. That is pretty loud, though. Would you consider a ball valve in part of the gun in the future? __________________ Forum rules

08-21-2006, 05:42 PM	#26
Ben Founder Join Date: Mar 2003 Location: College Park, Maryland Posts: 6,054 UserID: 1	Check out the pictures (again, I apologize for the enormous size). The air release is an old slightly damage ball valve that's perfect for this. The damage was external and allows the ball valve to rotate in any direction. I figured it would be ideal for this because in an emergency situation, time is critical and with a valve that can be turned in any direction it's that much faster. To clear this up to a few people who don't know: I don't use a schrader valve and never have used schrader valves. I've only used air couplers because we have so many automotive tools lying around it would actually be a waste of time to switch. That and air couplers have a better seal and are easier to work with. I've been busy working on getting a new website design preview made among other projects (you know...), so I haven't taken any pictures of the current muffler I have made. The current muffler is a very basic one that only absorbs the sound with some fiberglass insulation I had. I'm going to make a second one to use in conjunction with this that will have a cancelling effect (read HowStuffWorks for where I got my designs from). I'm also considering making a second, longer absorbtion muffler. The sound lasts a fraction of a second but still is extremely loud. In a water fight, this will give away your position. Ideally you'll use the air for something else. This is just another good reason to. __________________ email: / Forum rules / Read this page before emailing me. Do not send me a PM or email with a water gun question if someone else could answer the question. Post at the forums. You will get a response from me along with others' views or ideas.

08-22-2006, 08:40 PM	#27
Silence Administrator Join Date: Apr 2006 Location: Virginia Posts: 3,293 UserID: 576	If using this in a water fight, you'd need a system for pressurization anyway--not that you haven't thought of that. Perhaps if there was a hose leading to an air coupler on a WBL--that would be more flexible and allow for more practicality. On the other hand, a huge WBL barrel on top (or underneath, for that matter) of the weapon might act as a muffler in itself to some extent, especially if you put a flow restrictor (for lack of a better term) on the muzzle when not firing a water balloon. __________________ Forum rules

11-25-2007, 02:09 AM	#28
CplPunishment Junior member Join Date: Aug 2007 Location: Washington Posts: 7 UserID: 1369	Re: Supercannon II complete That Was Awesome. I would looooove to know the mechanics of this water gun, because I'm not completely sure what kind of system you used. Nice work guys.

11-25-2007, 06:08 PM	#29
Silence Administrator Join Date: Apr 2006 Location: Virginia Posts: 3,293 UserID: 576	Re: Supercannon II complete Take a look at this thread. Basically, there's a large tube with a plunger in the middle that separates the tube into two chambers. Water enters the front chamber through the nozzle, then the rear is pressurized by a pump via an air coupling. It may be hard to see the coupling in the pictures. The valve is opened and the air pushes the plunger and the water forward. __________________ Forum rules

11-26-2007, 08:38 PM	#30
Ben Founder Join Date: Mar 2003 Location: College Park, Maryland Posts: 6,054 UserID: 1	Re: Supercannon II complete Hey CplPunishment! I added you as a friend on Facebook. Supercannon II is a pretty simple water gun. SilentGuy described it well. If you want some more detailed pictures or explanations, let me know. Right now I'm working on a site update that'll include a lot of things like how to construct this water gun. Getting really high performance isn't hard at all. __________________ email: / Forum rules / Read this page before emailing me. Do not send me a PM or email with a water gun question if someone else could answer the question. Post at the forums. You will get a response from me along with others' views or ideas.

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