Douchenator Project

Guides and discussions about building water blasters and other water warfare devices such as water balloon launchers.
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atvan
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Re: Douchenator Project

Post by atvan » Mon Apr 02, 2012 5:54 pm

wetmonkey442 wrote:Don't take it above 100 PSI. Don't break that rule.

Also, do you have a gauge on the cannon, or does your pump come with one built in? Remember that the gauge on most bicycle pumps is not designed to be accurate above 100 PSI, because they are not normally used in applications above that pressure. I would say keeping it around 80-90 PSI on warm, cloudy days will get you the best results. As DX said, dividing the max pressure as temperature drops is a VERY good idea.
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Re: Douchenator Project

Post by wetmonkey442 » Mon Apr 02, 2012 7:07 pm

^

UV radiation is not very dependent upon how "clear" the skies are. See: http://www.straightdope.com/columns/rea ... loudy-days

Also, while exposure to high levels of UV radiation can indeed decrease the "strength" of PVC pipe, this really only translates to how impact-resistant the pipe is. Tensile strength (ie the stuff that matters when dealing with pressure) is NOT affected. See: http://www.nacopvc.com/c/technical-info ... n-pvc-pipe
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Re: Douchenator Project

Post by DX » Mon Apr 02, 2012 7:13 pm

Get a good floor pump with both presta and schrader heads. Those things are designed to inflate tires to up to ~130 PSI and will give you good readings in a WBL. I use an orange and black "Joe Blow Sport pump" and while it wasn't cheap, it's lasted many years and I see them used by bike repair people in stores (which is a good indicator of the quality of the model).

I wouldn't be too concerned about hearing when it's just a ball valve and below 100 PSI. The D2 Douchenator made a pretty low whooshing noise as opposed to the crack you get when using a very fast valve. It's much more like a thumper ejecting a shell than firing a gun. There's much worse things you can do to your hearing than that.

Eye protection should be used at own discretion. I bought a pair of rated goggles for use in Nerf that I'd probably end up using for any round with launchers involved. They are designed to come over my prescription glasses and do not affect my ability to run, dodge, etc.
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atvan
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Re: Douchenator Project

Post by atvan » Mon Apr 02, 2012 8:00 pm

Whoops. However, I have read countless things in other forums about PVC failing due to exposure to sun, but this is over several years in the sun for sometimes a dozen hours a month.
DX wrote:In the neanderthal days of K-modding, people would lop off the whole PRV
Well, not that much soakage.
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Re: Douchenator Project

Post by HBWW » Mon Apr 02, 2012 8:15 pm

@DX: Ben commented on the lack of pressure-rated 3"-4" fittings before; it's an iffy matter, but it's worth re-reading what he said about it here:

http://www.sscentral.org/homemade/aph/pvc-basics.html

I've also read a source over here: http://www.spudfiles.com/forums/nsf-pw- ... 15265.html

Now, I'm fairly certain that all of the 3" fittings I use are NSF-DWV as I've just had a look. With that, I'd say the fittings are safe enough to continue using that I wouldn't need to spend a ton of time and money replacing them. I'm also unlikely to go out of my way to look for fittings that give an actual number on their PSI rating. People have used these fittings for a long time without any reports of incidents, and I've used them on WBL's for a long time too.

I have a strict 80 PSI maximum rule on my WBL's. (Especially since one of them has a modded sprinkler valve blowgun rated at only 90 PSI.) I usually don't make shots over 60 PSI anyway, and they're more likely to pre-pop at this point. (Though that may be due to bad sabots and I have yet to test [or even finish some of] my new ones.)

Regarding sunlight exposure, my homemades are rarely exposed to sunlight due to rare use and the fact that they're ALWAYS stored indoors. If exposure is a concern, a good coat of paint should solve the issue.

That said, if I could press a button to turn all my launchers to those fittings (i.e. bushing and coupler connections that are obviously rated) and for all the stores to carry them, I would. However, I'm just not convinced that the risk is high enough to be worth the trouble.

Regarding sound, I'd only be concern if someone puts their ear up to the muzzle of a modded sprinkler valve based launcher. Outside of that, the sound levels are not loud enough to cause any damage that I'm aware of. The shots are made outside and there are no openings on the launcher to direct the sound in a way that would be harmful to your hearing. If you're using a ball valve, I wouldn't even think at all about ear protection. Worry about what actually matters, like the projectile launching or pressurization.

I did hear that you can fire guns outdoors without ear projection, but not sure how accurate that is. I have however, had some slight damage to my hearing as of late after going to a concert and I intend to never repeat that experience.
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Re: Douchenator Project

Post by SEAL » Tue Apr 03, 2012 4:00 pm

Updates: I made a sabot out of a sour cream container and a tennis ball can; it works very well. I also found some old water balloons that we'd brought years ago but never used. I fired 3 of them at 70, 80, and 85 PSI, but since they are oblong shaped, they didn't fly to far. I'm going to try to get some round ones tomorrow on the way to the gym.
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Re: Douchenator Project

Post by scottthewaterwarrior » Tue Apr 03, 2012 6:08 pm

Sorry if I am kind of being a noob here, but I have been following along (while being very quiet) and was wondering where you put air in this thing. My spring break is in another week so I might try and build one then. From reading/looking the pictures of SEAL's gun I have figured out how to make it except where you attach the pump to it. How does that part of it work? And SEAL, I hope you don't mind, but mine will probably end up being as close a copy as I can make it to yours, because I am probably less experienced with this stuff then you are.
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Re: Douchenator Project

Post by martianshark » Tue Apr 03, 2012 6:17 pm

There's a schrader valve somewhere on the PC - probably on the endcap.
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Re: Douchenator Project

Post by DX » Tue Apr 03, 2012 7:21 pm

Well, the most common method is to use compressed air delivered into the PC via bike pump. Universal schrader valves are a cheap ($2 or less) and popular choice. These are the same valves that car tires use and can be found in auto repair shops in addition to local hardware stores. They can also be found in bike stores, however you don't want the kind that attach to a rubber rim. For a WBL, you want a 1/4" threaded brass schrader valve. Bike stores also offer presta valves, but those are much more fragile than schraders. Good choice in a racing bike, bad choice for a WBL.

There are two options for installing the valve. One is to construct a line of reducers/bushings coming out from your PC using a tee and 90 degree elbow. This side port will allow you to screw the valve into a fitting of its size. With teflon tape, you get a perfect seal and it's just like screwing in any other threaded fitting. Downsides are that the connection is fairly fragile and must be protected from impacts. This can be the weakest link in your WBL, although it's probably the part that can take the highest pressure. This will also cost a bit more since you need more fittings. You will also need to find a metal reducer that can take you from 1/2" to 1/4".

The 2nd option is to tap the schrader valve directly into the side of the PC. You would do this where the pipe is thickest, like into the side of your endcap where it comes over the main pipe. This ensures that the valve is held in by all the threads and is thus most secure. Requires a hefty wrench in order to generate enough torque to twist the thing in. An adjustable hex shaped wrench is the best, since a brass schrader has a hex edge above the threads. Takes far less effort to get it in.
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Re: Douchenator Project

Post by HBWW » Tue Apr 03, 2012 10:52 pm

DX, I made the mistake of getting rubber-rim attached valves on my first WBL. Took a ton of time and epoxy to get it to work. Anyway, I find that the best method is tapping it in. It has made me paranoid in the past, but it works. You simply drill a hole the same size of the valve's threads (usually 1/4" NPT threads) and use a monkey wrench to get the valve in. Anyway, I couldn't find any proper Schrader valves except at the hardware store. Perhaps I didn't search far enough, but it seems that most Schrader valves at other stores are rubber rim attached or built into something.

If you choose to use reducers and fittings to step down to 1/4" thread for the valve, don't do it on where the endcap would otherwise go on the Douchenator or you'll have nowhere to rest the PC. For over-under designs, doing this is okay.

SEAL, what's your approach with the sabots? Good seal with ram-rod required, or okay seal that can simply drop in?
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Re: Douchenator Project

Post by SEAL » Thu Apr 05, 2012 10:44 am

I have the schrader valve in the side of the endcap. I'm pretty sure you can see it in the picture.

CA99: I will take a picture of the sabot when I make a second one. It's a very tight fit, and you definitely need a ram-rod, although my brother can actually fit his arm in the pipe, so we don't always need one. :goofy:

I also brought a 500 pack (These will last for a while!) of biodegradable round water balloons (That I will test later today.), along with a bike pump with a gauge that goes up to 200 PSI. I guess you can say that I have everything I need to make my opponent's lives miserable. :goofy:
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Re: Douchenator Project

Post by SEAL » Sat Apr 07, 2012 2:06 pm

Here is a picture of both my sabots.

Image

I fired the round balloons with them at about 70-75 PSI, and I think it shot to about 300 feet (Although my brother thought it was 250, so maybe we should say 275.).
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Re: Douchenator Project

Post by DX » Sat Apr 07, 2012 2:14 pm

Am I the only one who thinks that sabots should be looser in air powered applications? Think about Nerf, where springer barrels are tight fit and air barrels are loose fit. They are used that way because range is optimal that way. You put a tight fitting dart in an air gun and it just doesn't shoot as far vs a loose fit. I typically expect a bit more range than that at 70 PSI, but it really depends on a whole bunch of factors, especially the temperature, humidity, and wind conditions. Obviously, PC length and diameter will also affect the range. How fast you can open the valve matters as well, to a point. I agree with Wetmonkey that a valve opening too fast could potentially break the balloon with all the force hitting it so suddenly. With a ball valve though, you really have to flip that thing as fast as you can.
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Re: Douchenator Project

Post by SEAL » Sat Apr 07, 2012 3:11 pm

I used Waterwolf's guide when building these. I think you are the only person I know of who thinks they should be looser. I can make more however, so maybe I'll make a looser one next time, so I can see for myself which works better. It seems to me like they should be tighter so that less air escapes.
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Re: Douchenator Project

Post by HBWW » Sat Apr 07, 2012 6:10 pm

Barrel-bursting is not just caused by fast air release but also by a number of other factors. A tight sealing sabot may also contribute to the problem, as well as lack of sufficient balloon cradling and how far up the neck the knots are made on the balloon. I would say that a ball valve is unlikely to be able to open fast enough to contribute significantly to the bursting, though I will say that a better sabot seal and longer barrel should get better performance out of a ball valve based WBL. With this said, I may be better off trimming the barrel even further on my launcher with a modified sprinkler valve.
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Re: Douchenator Project

Post by briancof » Tue Jun 05, 2012 2:19 pm

Saw discussion of Schrader valves here and figured I would ask - does anyone know what the official "thread spec" is for those valves? In other words, if I wanted to buy an off-the-shelf "female" piece to fit a male schrader valve stem from (eg) a tire, what would I be looking for? I could be stupid here but this information has proven harder to find that I'd expect for such a common fitting.

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Re: Douchenator Project

Post by Andrew » Tue Jun 05, 2012 3:20 pm

This would possibly have been better in a new thread, but since it is here (and I'm not a mod :goofy: ) would something like this be of use (The image and description aren't brilliant, so ask before buying!)?

Schrader valves seem to have odd-ish size threads (details of which can be found on the wikipedia article).
Wikipedia wrote:External thread
Metric: 7.7 mm OD, thread root diameter is 6.9 mm × 0.794 mm pitch.
Imperial: 0.305 in OD, thread root diameter 0.271 in × 32 tpi (threads per inch)
Last edited by Andrew on Tue Jun 05, 2012 3:22 pm, edited 2 times in total.

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Re: Douchenator Project

Post by DX » Tue Jun 05, 2012 3:20 pm

Brass schrader valves are usually 1/4" NPT style threads. It should be a free-standing piece and not part of a rim attachment.
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Re: Douchenator Project

Post by briancof » Wed Jun 06, 2012 9:28 am

@DX: I'll double check when home, but I believe I bought a brass female 1/4" NPT fitting and found that it didn't fit. It's possible there are different types of schrader fittings.

@Andrew: That buy.com link you posted makes me think that schrader valves are similar, but not identical to, 1/8" NPT spec. Why else would someone need an adapter?

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Re: Douchenator Project

Post by Andrew » Thu Jun 07, 2012 6:49 am

braincof wrote:That buy.com link you posted makes me think that schrader valves are similar, but not identical to, 1/8" NPT spec. Why else would someone need an adapter?
To depress the pin! :lol:

I'm not completely familiar with NPT sizes (to be fair I've never needed to), but I know with BSP the thread 'size' actually refers to the pipe it connects to (for BSP it's the internal diameter of the pipe) not the actual size of the thread.

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