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PSI Question

Posted: Sat Jun 07, 2008 11:05 pm
by n-strike
Is there a way to figure out how much PSI is in your gun without a pressure gauge? Or would it just be better if I got a new pump with a built in pressure gauge? Thanks!

Posted: Sat Jun 07, 2008 11:17 pm
by drex
if you relly like math and gas laws, know the volume of your compressor and your chamber its possible but unpractical.

Re: How Much PSI

Posted: Sat Jun 07, 2008 11:35 pm
by starman
n-strike wrote:Is there a way to figure out how much PSI is in your gun without a pressure gauge? Or would it just be better if I got aa new pump with a built in pressure gauge? Thanks!
Nope. It's not really a big cost item...$5-10. You should install a gauge on all pneumatic guns...safety factor if nothing else.

Posted: Sun Jun 08, 2008 1:41 am
by n-strike
Drex: I have a pump, not a compressor. I am thinking of purchasing one though...

Starman: Couldn't I just get a pump with a pressure gauge instead of having to buy a pressure gauge for every pneumatic that I make?

Posted: Sun Jun 08, 2008 1:56 am
by DonTheLegend
You could, but those gauges aren't always the most accurate. I know the gauges on the pumps that i have are off by as much as 5 psi, but thats probably not that big of a deal. As starman said, its not really a big cost item though.

Posted: Sun Jun 08, 2008 2:02 am
by starman
n-strike wrote:Drex: I have a pump, not a compressor. I am thinking of purchasing one though...

Starman: Couldn't I just get a pump with a pressure gauge instead of having to buy a pressure gauge for every pneumatic that I make?
Well you could, but what happens when you disconnect the pump hose...no way to know what's in the tank. It's nice to know for sure if you've got a charged tank or not if the gun is just lying around.

Do the gauge, like I said before, the cost is minimal really.

Posted: Sun Jun 08, 2008 2:16 am
by THUNDERLORD
Since your using a pump, not the best method but you could count the number of pumps and check the pressure.
As long as your well below the maximum pressure the pressure won't vary extremely.

I know with my bike pump, I have to jump on it to get about 90psi anyway so then I get bored and shoot something.

Starman's advice is good and a gauge is needed for better accuracy/safety.

I was thinking of a really cheap way to rip the top off a stick type tire gauge, wrap rubber piece around it and small hose clamp then drill a hole in an end cap with epoxy and permenantly mount it off a T on the chamber. (Mine will probably be digital though).

But that type gauge usually only go to 100 psi and aren't as accurate.
BTW(They do have enough pressure to press a switch for use as a homemade pressure switch) :wink:

Posted: Sun Jun 08, 2008 2:23 am
by kablooie
Yeah, gauges are extremely useful on the gun, because for me the schrader valve-pump connection often leaks, being able to disconnect the pump and see if your gun leaks, or just how much pressure is in the chamber, is very useful when trying to get regular results. You could get a couple of gauges and then switch them from gun to gun (assuming they are threaded into an actual fitting and not the side of the pipe).

Posted: Sun Jun 08, 2008 12:33 pm
by D_Hall
Personal opinion: If you can't afford pressure gauges, you can't afford this hobby.

Posted: Sun Jun 08, 2008 1:02 pm
by starman
D_Hall wrote:Personal opinion: If you can't afford pressure gauges, you can't afford this hobby.
Amen Bro! Words to live by.

N-strike, could it be that you aren't confident drilling and tapping a 1/4" NPT threaded hole? It's really easy especially in PVC. Just need a 7/16" drill bit, a drill that will chuck up to 1/2" (preferably a drill press), a 1/4" NPT tap and an adjustable wrench...all available at your favorite Lowe's or Home Depot.

You'll need to hold the pipe you are tapping very firming while you drill your 7/16" hole...put it in a vise or have someone stand on it. Take your time drilling the hole. Then just start the tap straight in the hole you drilled and start screwing it in with the adjustable wrench....backing it out slightly after every turn. When you've tapped in to about 3/4 of the tap, you're done. Back the tap out and try your gauge in the hole. A little teflon tape will help seal it.

Posted: Sun Jun 08, 2008 1:59 pm
by n-strike
That's true, D_Hall. And Starman, I am definitely confident. I just don't have a job (hehehehe) and I don't get allowance, or any source of income...so once I spend my money, I have to wait for...someone to buy my stuff, a garage sale, or even when my dad just won his hockey pool since Detroit won the Stanley Cup! (yay) Only because I have more than enough money now, I will buy a pressure gauge, and maybe save some money for a future project or something. And this question is a little off topic, but I didn't want to start a whole new thread. My question is: What size drill bit do I need if I'm gonna drill a hole in a sprinkler valve for a 1/4" brass nipple?

Posted: Sun Jun 08, 2008 2:30 pm
by TurboSuper
I didn't put a pressure guage on my pneumatic. I don't want to go to a specialty shop that sells one that will go >60 PSI, and my compressor has a gauge anyways. My pipe is rated to well above whatever I'm pumping in there, so it's fine if the compressor is off by a few PSI.

But if you can find a gauge, by all means, get one. They look pretty cool.

Posted: Sun Jun 08, 2008 2:47 pm
by n-strike
Haha, yeah...They do make it look a little cooler...

Posted: Sun Jun 08, 2008 4:52 pm
by DonTheLegend
1/4" NPT requires a 7/16" drill bit

Posted: Sun Jun 08, 2008 6:48 pm
by psycix
I recommend installing a gauge on your cannon. Pump gauges tend to give wrong values (usually too high).