Douchenator Project

[scottthewaterwarrior]

I am trying to build a Douchenator - that's right, the guy that has almost never even taken a water gun apart is trying to build a WBL. I need help and I figured, why make a new help thread when a perfectly good one already exists?

Anyway, I loaded all three pages of this thread up on my laptop and went to Home Depot. Long story short, I couldn't find a reducer that went smaller then 1 1/2'', I realized all the stuff I had got so far was rated Schedule 40 NFS-dwv (insted of just NFS), and no one there even knew what a schrader valve was. After two hours, I had gotten nowhere and was pretty hungry, so I put everything back and left. I probably should have bought the brass valve ($18), but I was too mad at the time.

So questions I have:
*What the difference between NFS and NFS-dwv?
*What is Schedule 40?
*Where do I even buy a schrader valve?
*How can I get from 3'' PVC to 1" PVC if none of the reducer's go smaller then 1 1/2"?
*And while I'm at it, what glue should a buy?

Maybe the more northern Home Depots are different, but I found this local one annoying and unhelpful.

[HBWW]

*NSF. Designations for pipe. Just "NSF" means it meets several specifications for water tap (i.e. won't contaminate the water), and I'm pretty sure means it can take pressurized water. DWV means Drain/Waste/Vent. NSF-DWV means it can handle DWV as well as pressure. For pipe, make sure you can see a pressure rating. Fittings generally don't have them, but should at least have a DWV designation. You want to be careful here as it is a bit unclear at the 3" or larger fittings. (Some drainage fittings are NOT SAFE to use, some are in the grey zone, meaning they've been used for WBL's by one of us and we haven't had problems with them so far, but the shorter slip connections [when you push a pipe/fitting together] are a concern.) This thread may help: http://www.spudfiles.com/forums/nsf-pw- ... 15265.html

Pipe schedule is the size standard of the pipe. Higher schedules are thicker and stronger pipe. Schedule 30, 40, and 80 are most common; the community generally sticks to 40 almost exclusively.

Schrader valves should be available at the hardware store. I know ACE carries them, not sure about ACO. (Make sure you buy proper Schrader valves, not something with rubber coating or whatever. I made this stupid mistake on my first launcher.)

Back to fittings. Several Home Depots I've been to have been terrible with fittings and pipe parts. My nearest Home Depot doesn't even carry check valves below 1 1/4". Lowe's is generally my go-to for most PVC parts I need, but sometimes I need to go to ACE (for PVC nipples) or order online at McMaster Carr (threaded/compact check valves). As for reducers, I'm aware of two main options:
- At Lowe's (at least at my local one), there are 3" bell reducers that go to 2" or to 1 1/2". I usually take 3" to 1 1/2". Then I go to the smaller PVC fittings section and get a 1 1/2" bushing that takes it down to 1" or 3/4" or whatever it's supposed to go to.
- McMaster Carr carries a 3" bushing that goes directly to 3/4". You will also need a coupler since bushings are sized to the pipe.

The fittings at McMaster Carr look suitable for pressure, judging by the diagrams. However, I haven't tried any myself.

As for glue, it depends on what you are doing. If you're sticking PVC together, you only ever use PVC primer and cement. (Solvent welding.) Both primer and cement are needed and must be used. Do not use anything else as it will not work as well, or work at all. In a nutshell, the primer (typically a purple low-viscosity liquid) is applied first to all pipe making contact with fittings or other pipe. After that, the cement is applied (again, to both pipe parts going together). Primer can sit and dry a bit before cementing, but you shouldn't wait too long. Join the pipe immediately after cementing; use a lot of force, twist it a bit, and ensure the fitting goes on all the way. Hold the two parts together shortly so the pipe doesn't push the fitting out. Here's a full guide, but if you're not using the Oatey brand of primer/cement, you should follow a different one. http://www.oatey.com/doc/OA_Tri-fold_Ho ... ch2013.pdf

[scottthewaterwarrior]

OK, I am really showing my ignorance here, but...
*What is a bushing?
*What is a coupler?
*Wait, I need check valves now? I don't know what that is ether.

I have only ever used PVC to make foam swards by gluing pipe insulation to them. As far as connecting them together goes, the first time I ever did that was today at the store. Beyond physically taking parts and seeing if they fit together, I don't know how to tell what attaches with what until I try it.

[HBWW]

Start with reading up on SSC articles. Google helps too. Also, see if a friend or family member knows how to do this sort of stuff.

Check valves are one way valves we use in water blasters, don't need them in launchers. (Well technically you do, but they're not the ones you usually buy.)

Edit: Moar info.

Coupler: Simple fitting that is typically used to connect two pieces of pipe together. (Just slip both ends into it.) Looks like this: http://www.askmehelpdesk.com/attachment ... upling.jpg

Bushing: Fitting that connects larger and smaller ends. Larger end is either a spigot or male thread, smaller end is either a socket or female thread. Photo: http://flexpvc.com/pictures/ReducerBushing2.png

To connect parts, the connection type must match as well as the size. Sizes of Schedule 40 pipe typically come in 1/2", 3/4", 1", 1 1/4", 1 1/2", 2", 3", and 4". Larger pipes are available but not typically used by the community.

There are two main types of connection: slip and threaded. Slip connections require a socket and spigot (or the pipe itself). For example, if you stick a typical 1/2" 90° elbow on a piece of 1/2" pipe, the elbow has two sockets and the pipe end acts as a spigot. Some elbows actually have a spigot end that can insert into a socket.

Threads work the same way. Threads can be male or female and all follow NPT (National Pipe Taper) standards, which means any part that follows the standard can connect to PVC. (This is how you can connect metal parts to plastic, for example.) Common NPT sizes we work with include 1/4" and 3/8" for smaller parts.

Best way to figure it all out is to go to Lowe's or the hardware store or something and ask about it. Try sticking things together. There are lots of parts out there and it's good to know what's around before designing your first homemade. I could've saved myself a lot of work and resulted in a better CPH design had I been aware of that...

[DX]

DWV means Drain/Waste/Vent. NSF-DWV means it can handle DWV as well as pressure. For pipe, make sure you can see a pressure rating. Fittings generally don't have them, but should at least have a DWV designation.

Be really careful with that assumption. A fitting is pressure-rated if it says NSF-PW, for potable water. It is also rated if it says both NSF-PW and NSF-DWV, in which case it meets both standards. NSF-DWV is not officially pressure rated. It can definitely handle pressure, but is not explicitly meant to, so use at own risk. You can visually tell the difference between DWV and PW fittings. PW fittings have deeper sockets and sometimes thicker wall.

Anyway, I can tell that Scott is getting confused, so we really need to keep the explanations simple.

*Schedule 40 is the most common variety of PVC. Almost everything you find in a typical hardware store will be schedule 40.

*Small or local hardware stores are more likely to carry schrader valves. Bike or auto shops also might have them, since schrader valves are on your tires. Tenleytown Ace Hardware should have them. You want a 1/4" NPT threaded, brass schrader valve and it looks like this:


*They don't make bell reducers that can take you to 1". Instead, you need to use a bushing to make the jump. Make sure both the reducer and bushing use smooth (slip) connections rather than threads.

*Oates PVC primer (purple can) and PVC Cement (brown can). Often sold in a bundle for a reduced price.

Visual instruction guide for a basic, inline Douchenator:

OK so you have your 3" cap, which looks more or less like this:

You cut a length of 3" pipe for your pressure chamber.

The cap goes on one end. Your bell reducer goes on the other, which looks something like this:

The larger side is 3" and the smaller side is say, 1 1/2". You want to get a 1 1/2" to 1" bushing, which looks like this:

You shove the bushing directly into the reducer. You shove 1" pipe into the other end.

Then, you put a 1" male adaptor on that pipe, which looks like this:

Your ball valve threads into the male adaptor.

You can clearly see the female threads, which will be at both ends of the valve. You thread another male adaptor into the other end of the ball valve.

A piece of 1" pipe goes into that.

Then, you simply use another bushing to reducer combo in the other direction.


This will step the pipe back up to 3" for your barrel.

To get the schrader valve in, you can either construct a tree or drill a hole in the cap and twist it in. The latter is easier and safe if you do it correctly. Do not drill into the center of the cap, drill the hole into the side of the cap where it is glued over the 3" pipe. This is the thickest point. Drill the hole at a diameter that is slightly smaller than 1/4". Simply use a wrench and try to thread the valve into the hole that you've drilled. It may take several tries to get it all the way in and straight (what she said). Make sure the valve stem goes all the way in, to the point where the non-threaded part is resting on the pipe surface.

Do not do this until you've glued the cap and let it dry completely. I wait 48 hours because I don't mess around with this critical part of WBL construction.

[marauder]

I seriously think my design is superior to the Douchenator, but then again I really can't talk because mine didn't work. That still bothers me. Maybe I put the Schrader Valve in backwards, but I swear we double checked that.

[HBWW]

I still haven't seen the launcher. Any photos/diagram drawings of it?

[marauder]

Unfortunately, no. They were all on my iphone. I will get around to looking at it eventually. My parents aren't going to just throw it out.

[HBWW]

I'm pretty curious because whenever a design is supposedly superior to a Douchenator, it always has an asterisk next to it. (One of my favorites I've seen having parts that were never documented and probably require a trip to Mordor to find [or required some insanely stupid step like sanding out a coupler so it fits over a pipe; ain't nobody got time for that!], others just not matching up in the simplicity/low cost of construction, etc.)

[DX]

It is easy to build something with better performance than a Douchenator. However, with 13 total parts (8 of which are symmetrical pairs), the cheapness and pure simplicity of the Douchenator is tough to beat. When operated with a plain ball valve and tapped schrader valve, it just works. There may be an air leak, but it's no mystery why or where. Due to us not using the longer ranges a more powerful design is capable of, I don't see myself doing much with WBLs other than try to improve upon safety. I'd like to look into LPA canisters and similar, safer alternatives for the PC.

[marauder]

I'm not much concerned with improving on the Douchenator's power or range either. What I liked about my design, however, was that it was going to be a lot easier to aim and fire, and you could pump it up as you ran around carrying it.

[scottthewaterwarrior]

Couldn't you do that with the Douchenator by just tapping a bicycle pump underneath it? IDK, I'm not to knowledgeable about these things. I used to think the way to build a WBL was to put a giant bungee device inside of a tube. I was going buy those long party balloons and put fins on them too! I figured the fins would make them fly like missiles!

But I have always had "elaborate plans," before water warfare, I wanted to do airsoft. I was going to make big peddle powered tanks with bunks, and minifridges! One of my designs even had a fold out runway to launch airsoft equipped RC planes. I never did any of those things, which is why I am trying to use an established design because I might actually accomplish something then.

[HBWW]

I consider Douchenator performance to be satisfactory, the most efficient improvement that could theoretically be made being slightly improved sabot seals. (I understand the whole looser barrel fit with Nerf thing, but all Nerf darts have some sort of seal to begin with, while most muzzle loaded sabots that don't require a ram-rod hardly even touch the walls of the barrel.) Improvements from there would be to rate of fire via improvements to ergonomics and/or pressurization rate, as well as loading method. The only real benefits to breech loading over muzzle is if you have a long barrel or insists on sabots that seal better, but don't want to use a ram rod. (As far as I'm aware, no sabots are around that seal perfectly; in theory it would take way too long to muzzle load such a sabot.)

Anyway, I found that in the end, some of my launcher designs' deficiencies included the following:

- 2" barrels suck because of how small you have to fill the balloons as well as having to make a different set of sabots for them. Their advantages include a breech design that's relatively easy to build and they require less power/less pumps. I haven't found out whether that's really worth it though.

- I'm still a big fan of modified sprinkler valves, but if you go with a ball valve, it really must open quickly. The PVC valves I used from American Valve are terrible; even with a huge torque arm (that makes it extremely difficult to aim direct-fire), its opening is still very sluggish. Very old valve that hasn't been lubed either, but I no longer can because I insisted on building a launcher that couldn't be disassembled.

- It's generally worth the space/money savings to tap Schrader valves and pressure gauges. Obviously just have to make sure its done right. If it's something you can't do for whatever reason, then build a tree (term coined by DX, referring to series of small pipes after a pressure chamber such as the one seen on the SuperCannon II.)

For Scott, I'd just recommend the Douchenator. The simplicity is great for new builders but does not compromise on usability. Definitely use a metal ball valve, only use PVC if you find one that opens fast. The valves I found at ACE open faster than metal ball valves (and I'm seriously considering experimenting with them), but metal valves may improve with lubrication. Never solvent-weld the whole launcher; always leave threads on there so it can be disassembled and/or parts can be replaced.

For the Douchenator, I'd build one on the shorter side this time. My first WBL, initially a Douchenator, was horrible to carry around indoors due to its length. It had a 2' PC and 3' barrel; I recommend shorter to avoid having to disassemble to carry it indoors. 1' PC and 2.5' barrel should work, although DX would make better PC/barrel length recommendations than I would.

I ended up never getting into Airsoft. I had enough equipment to worry about in water warfare and even in stock Nerf, that I just never found the time.

Scott: When you actually go and build something that works, it's not only a lot of fun, but you learn things that'll take you far beyond the hobby. I now know a bit about plumbing in general after building homemades and could probably make a few repairs around the house should the need be presented. (i.e. Replace a sump pump.) Keep in mind that, used appropriately, this stuff is designed to last decades without leaks/problems, so the majority of a well-built homemade (used properly) will last a very long time. Things like pipe cracks on a standard APH simply aren't possible unless caused deliberately. (Or with weirdly stupid mistakes.)