Pressure Gauge

Build a homemade water gun or water balloon launcher and tell us about it.
Prof_Slammin
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Pressure Gauge

Post by Prof_Slammin » Thu Jun 08, 2006 12:12 pm

I'm trying to make a series of gun for my tech exposition in my Jonestown Battles (see water fights section). Would anyone know how to make a good working pressure gauge, as well as the equipment I will need.. A pressure gauge would be helpful in certain ways (in a way it can tell how fast the water is going and give you a good overview of the gun's performance).

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Silence
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Post by Silence » Thu Jun 08, 2006 3:57 pm

It's hard to build a pressure gauge yourself, but they are fairly cheap and can easily be attached to PVC tubing. You should note that a soaker isn't the best of the best just because it has the greatest pressure--focus on efficient designs (linear flow) and battle practicality.

You might want to wait a year or so before you actually have Jonestown Battles...for now, there might be the Northeastern Regional Water War, and you could just have an informal battle with your friends. Good luck, though...

Prof_Slammin
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Post by Prof_Slammin » Thu Jun 08, 2006 7:18 pm

I was thinking the same thing with the Jonestown Battle so I'll see if I still want to run it. But for the pressure gauge, atleast I know where to put it. I'll try this plan.

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SSCBen
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Post by SSCBen » Thu Jun 08, 2006 9:34 pm

Your best bet would be to buy an existing pressure guage. I own maybe 5 or so different ones simply because they are so useful (three are on a single water gun too). You can buy pressure guages typically where air compressors are sold at home improvement stores, and you will need a coupler to attach the 1/4" thread to 1/2" thread.

Building your own pressure guage would be hard and not very accurate. Calibration would be difficult and inaccurate. A home-built one also would be more expensive likely. Stick to an existing pressure guage.

Prof_Slammin
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Post by Prof_Slammin » Fri Jun 09, 2006 12:08 pm

Ben wrote:Your best bet would be to buy an existing pressure guage. I own maybe 5 or so different ones simply because they are so useful (three are on a single water gun too). You can buy pressure guages typically where air compressors are sold at home improvement stores, and you will need a coupler to attach the 1/4" thread to 1/2" thread.

Building your own pressure guage would be hard and not very accurate. Calibration would be difficult and inaccurate. A home-built one also would be more expensive likely. Stick to an existing pressure guage.
I can probably some at Home Depot or Walmart because the have a home improvement section. So how exactly do I put on the gauge to make it work.

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Silence
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Post by Silence » Fri Jun 09, 2006 4:05 pm

I've never exactly used a pressure gauge, but I can imagine how it would work...

You add a reducing tee somewhere between the ball valve, the PC, and the second check valve; and one of the legs of the tee has an ID of 1/4". There should be a smooth female adapter on the pressure gauge, and you just coat both surfaces with primer. Then, after several hours, coat both with cement and press them together, twirling the pressure gauge a bit to ensure that the glue is spreading around and creates a strong seal.

Prof_Slammin
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Post by Prof_Slammin » Fri Jun 09, 2006 4:16 pm

How much do you people think that a pressure gauge would cost. I want about 2 because I want to make APH and WBL.

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Silence
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Post by Silence » Fri Jun 09, 2006 4:37 pm

First of all, you should be able to distinguish the pressure of a WBL by looking at the analog pressure gauge in the Schrader valve as you pump. However, if it is to be a MS WBL, then you might need an additional gauge--unless, of course, you carry and/or pump the Schrader valve.

I wouldn't imagine that this costs too much...certainly no more than $5-10 (don't hold me to the estimate, though).

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m15399
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Post by m15399 » Fri Jun 09, 2006 5:49 pm

No check valve between the gauge and the PC's. If there was one, the pressure would go up to the pressure in the PC's and stay there for the rest of eternity.

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Silence
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Post by Silence » Fri Jun 09, 2006 5:53 pm

No, I said to put the gauge between the check valve and the PC (or after the PC, for that matter); not to put the check valve between it and the PC.

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SSCBen
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Post by SSCBen » Fri Jun 09, 2006 7:10 pm

Last time I checked, a pressure gauge costs $7 here locally. The brass fitting that converts 1/4" ID threaded pipe to 1/2" threaded pipe wouldn't cost more than $3. Pipe thread tape won't get worse than $2 if you get the most expensive kind. That's essentially all you need to attach a pressure gauge to a 1/2" female threaded spot.

You do not need 1/4" PVC or anything of that sort. It is easier and cheaper to simply use a small brass fitting to convert the sizes.

Connecting them together is so obvious when you have them that if I had to explain it, I'm quite confident that you wouldn't be able to do it anyway. Just apply the thread tape and screw everything together well. ;)

I'll get a picture once my digital camera starts working.

Prof_Slammin
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Post by Prof_Slammin » Mon Jun 12, 2006 12:29 pm

It would be really helpful if you were able to take pictures of a pressure gauge. I never knew they would cost over $1because all they do is take pressure. Don't get me wrong I know they are useful, but why do stores, that have so much money, make you pay so much for one little piece of a huge puzzle. Funny thing is, Walmart says "low prices, always". Tsk, gimme a break.

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SSCBen
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Post by SSCBen » Mon Jun 12, 2006 4:09 pm

That is a low price.

A pressure guage contains a lot of little parts and machining those parts obviously costs money. The pressure gauge also has to be built to handle high pressures. These are good accurate pressure gauges as well. They are calibrated to be correct within a certain limit usually. Cheap pressure gauges do exist such as those in the Super Soaker water guns, but those are little aside from a spring in a tube with a gear to turn a dial. Those gauges don't last very long.

Why do PVC couplers cost more than a penny? Those cheap capitalists are making $0.19 for a penny's worth of plastic. :p

Prof_Slammin
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Post by Prof_Slammin » Tue Jun 13, 2006 8:14 pm

I was wondering if a oil pressure gauge would work because there's a local shop, but that's all it has (accept for voltage gauges).

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SSCBen
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Post by SSCBen » Tue Jun 13, 2006 8:42 pm

Any shop will have more than an oil pressure gauge, even a car shop. I am sure that there are differences between the two gauges, but I am unsure of the differences. I can not tell you definitively whether or not an oil pressure gauge will also work correctly for air pressure.

Car shops typically have a section for air compressors and air tools. Home improvement stores typically have a section for air compressors and air tools. Even Wal*Mart's car section has a great selection, in fact, their prices typically are much better than Lowes' or the car shop's. You're not looking in the right places (hint: they're almost never in or near the same section as PVC).

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