New Air Pressure Homemade

Build a homemade water gun or water balloon launcher and tell us about it.
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DX
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New Air Pressure Homemade

Post by DX » Wed Jun 28, 2006 12:27 am

Ok, I am making [well, putting together] a new homemade specifically for this next war. I am probably going to use the N00b Killer's 2" inverted T pc with the APR 2000's 3" reservoir. [Neither are working, and I'm short on money, so I might as well]. As for the pump, I may try a non-tracked, since my hacksaw's blade is so bent that it wouldn't make the track straight enough. I don't have a drill press or anything fancy, so everything has to be cut by saw/regular drill. What would be better, a 1/2" pump or a 3/4" pump? The ID of the rest of the gun's pipes is 3/4". Although 1/2" gives more leverage, it is easier to make a non-leaking pump for a 3/4" shaft.

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I will finish this later, I'm going to go shoot a glowing orange at a friend's house with his Douchenator. Be back in about half an hour or something.
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Silence
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Post by Silence » Wed Jun 28, 2006 7:08 pm

Good luck with this homemade, and I'm glad that you're doing this at least partly due to my insistence on the battle practicality of homemades. From what I've read, go with the 1/2" pump--if you read the article about Pepper's homemade, you'll notice that he only got a little more than 30 feet of range due to the large 3/4" pump. (A 3/4" pump homemade might make a good short-range backup, though) You might get 40 feet, but that's pushing it, and even with the admittedly large size of his PCs, "the pump became wickedly hard to pump" after only 5 or 6 pumps. A 3/4" pump has 9/4 the area of a 1/2" one, but it makes a huge difference. Note that I say all this with no experience, though...just a good amount of research.

Do the other guns not work due to seal leaks, or due to a different problem? No offense, but it might be time to start using primer if there are leaks--it's recommended by professional plumbers, and in a current thread, somebody mentioned a leak due to the lack of primer. Fortunately, though, if there is a leak, epoxy might do the trick as it did for the person I am referring to. Anyway, good luck with this, both in building and in battle.

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Post by DX » Wed Jun 28, 2006 10:04 pm

I always use primer, I didn't at first, but realized that the chances of a part coming off are heavily reduced if you take the 5 minutes extra time to use the primer. The other guns mainly do not work due to bad pumps, especially on the 1/2" pumps. I have problems where the ID of the O-rings is the same or slightly larger than the OD of the rods, which is bad because when placed on, the O-rings expand a little. However, that is enough to cause the rod to refuse to go into the pump shaft. It is actually better to get O-rings with an ID safely smaller than the OD of your rod, since you can always put a layer or two of tape under the O-ring to raise it.

I only use a gun as a backup if it has range near my primary, so you won't see me with a short range gun, ever really. My homemades which use 3/4" pumps fire in the 40s and the stream speed is terrible [hence why my modded guns absolutely blow away my homemade stream speeds].

I don't feel all too confident, so I will be using a water cannon as a sidearm/backup. Normally I won't carry anything other than my primary and a refilling can, but this time I need the protection of the cannon.
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Post by Silence » Thu Jun 29, 2006 1:10 am

Well then, I can certainly understand how you adjust very often--much of what was in the last post was new to me, especially your use of primer--though the SM thread in which you mentioned primer is pretty old, actually. Anyway, good luck on this homemade, as I understand you are nevertheless making a couple of decisions you don't usually do--which isn't necessarily bad by any means. By the way, you could check out the O-ring selection at McMaster-Carr or check your phone book for listings of O-ring suppliers. Ichabodv, I believe, had his LRT arrive on the same day he ordered--so it might not be too late. Hopefully, a combination of smaller pump diameter and a good seal might provide a somewhat better homemade, so good luck with that.
Duxburian wrote:However, that is enough to cause the rod to refuse to go into the pump shaft.
Umm...was this a slight terminology confusion? It's not that big a deal, but it might be slightly confusing to some.

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Post by DX » Thu Jun 29, 2006 2:13 am

I buy O-rings at the local Sears=here in northern NJ, you can buy anything and everything within the county. A pack of 4 O-rings is about 30-70 cents, depending on OD.

As for primer, etc. everything I've said before tactical theory popped up can basically be thrown out the window. My attitude towards something can radically change in just one battle. 2 hours can make me take a 180 turn on any aspect of soaking.

This is definately going to be an odd battle. I am going to need to refill more than often, and that will suck. I will therefore have to shoot less often and engage at closer ranges to save water. Refilling often = death unless the teams are in totally different ends of the battlefield. Also, no one will be able to ford due to the high water. The brook almost burst its banks this morning, and it did further upstream. Since we are to expect more rain every day for the next week [again], that probably won't change.

As for the pump shaft, like think literally, not mathematically. Picture some guy trying to get the rod to fit into the pump shaft, and the rod won't fit because the O-ring is twisting and the whatnot. There's no terminology in that statement...there's 3 parts to a pump: the pump itself, which is a wooden or aluminum rod, the pump shaft, which is the piping it goes into, and the handle, which is in different positions for tracked and non-tracked pumps. The pump shaft is not the pump rod, if that's what you confused, think of a mine shaft, which is the opening which contains whatever is going up and down in the mine, or an elevator shaft, etc.
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Post by Silence » Thu Jun 29, 2006 2:22 am

Oh, I guess I've been under the wrong impression this whole time then...I've been using "pump shaft" and "rod" interchangeably, and using "pump tube" in this context. I'll change that usage, so thanks for pointing it out.

With the O-rings, I was referring to selection--if you select an OD at McMaster-Carr, you'll have many options for the ID, too. The increments are incredibly small, and if I was forced to order an O-ring there, I probably wouldn't even know which one to get (too many choices can be bad for me)! At any rate, I suppose I could order several at a time due to the cheap price, and put them on different pump shafts--though that definitely won't happen soon.

Trust me, I won't bug you with pointless questions and comments concerning this again :rolleyes: ...

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Post by joannaardway » Thu Jun 29, 2006 7:46 am

Your problem with homemades may be dependant on the 3/4" pump.

The lower pressures produced are probably the issue limiting stream speed.
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Post by DX » Sat Jul 01, 2006 3:51 pm

Instead of the original idea, I am making this gun from scratch. I would rather use a larger pipe for the pc than the n00b killer's 2". The new 3" inverted T pc will also need a larger reservoir, hence the switch to a new gun from scratch. Due to the size, I might as well make this the APR 3000, the next step up from the APR 2000. I am assembling and gluing today since I couldn't contact Belisaurius to set the date for the war yesterday. Hopefully it will be set for this Sunday. The current specs of the homemade:

3" Inverted T pc with schrader valve pressurization option
1" Metal Ball valve with 1" riot blast opening
1/2" non-tracked pump [I'm going to try one]
3" On-board reservoir [In the usual APR style]
3/4" connection piping

This is my 9th homemade if you count water cannons [so despite arguments over battle practicality, I am certainly not anti-homemade :p ]. I have taken a lot of things into account for this gun, including taking extra care to make sure the pump can build up enough pressure to get good stats. That also means going to Sears to get some smaller O-rings and spending time getting the seal right. I am going to test the pump as a PVC Piston Pumper before actually attaching it. Only when it shoots water perfectly leakless will I glue it onto the APR 3000. :cool:
Last edited by DX on Sat Jul 01, 2006 3:59 pm, edited 1 time in total.
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Post by Silence » Sat Jul 01, 2006 4:11 pm

Sounds good--there's a lot of innovation in this design. One question, though: What do you mean by
3/4" connection piping

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Post by DX » Sat Jul 01, 2006 4:16 pm

Like the size of the PVC in between most of the parts. From the pc to the reservoir, all the connections are 3/4". The pump steps down nicely to 1/2", since I found 3/4"-1/2" bushings, amazing little fittings! I also took care to make the step down from 3" to 1" at the ball valve smooth. The check valve side of the pc has a very compact step-down to 3/4", but on the ball valve side, I made it stretch a bit longer, to help with fluid flow.
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Post by Silence » Sat Jul 01, 2006 4:28 pm

And I think I'll ask a few more specific questions, if you don't mind...

So, is the second check valve 3/4", or do both bushings/reducers come after it (probably cheaper the latter way)? I do agree that the bushing are great--you can barely see them if you put them right into the PC tee on homemades that use standard tees.

And on the ball valve side, did you make the PVC stretch a bit longer before the reducer, after the reducer, or after the ball valve? Also, the metal ball valves I saw that used socker joints didn't seem to fit properly with PVC; maybe I just messed up, but it really didn't form a seal at all. I just used the female thread metal ball valve, and I even used spigot plugs that go directly into the fitting rather than a threaded endcap.

I didn't know this homemade was going to be so big, but I guess the on-gun reservoir is part of that. I'm surprised n00b Killer got decent range with what I now know was only 2" PVC PCs, but maybe it's different for the inverted-T style. Also, I still don't know if the surface area of the water in the PC makes a big difference.

Slightly off-topic: in the future, once the PCs of my compact APH are glued, I might build one of those concept homemades that have screw-on PCs with ball valves. I could have both a 2" and a 3" PVC, and that might end the unregulated-CAP debate once and for all...

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Post by DX » Sat Jul 01, 2006 4:49 pm

Both check valves are 3/4". The second one, however, is immediately followed by the step-up to 3" using all bushings to make it short. I could not find a rare 3"-3/4" bushing this time, so I settled for a combination which got me there. Store people have told me that such a piece does not exist, but I have found a limited few on certain trips. The pump reduces to 1/2" without even being visible, due to that nice 3/4"-1/2" bushing. I didn't know that piece was an option until last night! I've used bushings for quite a while, but those 3/4"-1/2" ones are amazingly useful things I never knew about.

The ball valve side uses a 3"-2" reducer, then a couple bushings. This allows the water in the pc to leave without being forced into a small opening as quickly as if it were all bushings all the way.

Always use threaded metal ball valves. This is their best feature, so you can switch barrels and pcs. You don't have to do anything special to get interchangablility. Despite torque arms making PVC ball valves faster, I have yet to see a threaded PVC ball valve...

I am trying to keep the gun as small as possible while keeping it powerful. I will need a sidearm on my back, so forget a backpack for this. If I ever make the APR 4000, that might need a backpack, but the APR 3000 won't.

A homemade with a 2" pc can clear 40-45 ft no problem. However, you can feel the lack of power in the stream. So I'm going with 3", which has more potential for range and stream speed. The smaller pump will also make more of a difference with a larger pc diameter.

I don't use any math for these guns, since fluid mechanics and physics don't come very naturally to me. Logic dictates what I use, then what I change for the next gun. I let others figure out why something works best mathematically, I just use and figure out what works best logically. Some here would shudder at the thought of not applying math for a homemade, but I've made 8 without it. :rolleyes:
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Post by DX » Sat Jul 08, 2006 1:33 pm

Image

^I think the original picture was lost when I renamed it, so I reposted it just in case.

I really head-whiffed in terms of getting this gun ready. I'm still missing a single part, and totally forgot to buy it. So now I can't use the gun in today's war, and it will have to wait a week for battle debut. That was really stupid of me... :rolleyes:
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Post by WaterWolf » Tue Mar 13, 2007 9:20 pm

Sorry for bringing a dead post back to life, but what-ever happened to this gun?
Things seemed to be going fairly well, then it just stopped in its tracks.

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DX
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Post by DX » Tue Mar 13, 2007 11:50 pm

I decided not to build the APR 4000. I realized that it would be so top-heavy and eat water so quickly that it would just be a waste. Many of its parts ended up in the N-Rev Challenger instead, which sports a far superior design to the APR homemades. From now on, I'm only building unconventional N-Rev homemades, which can be powered in any way, take any shape, and can actually be used in local wars.
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