PSI Question

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
User avatar
n-strike
Specialist 2
Specialist 2
Posts: 219
Joined: Sat Apr 26, 2008 3:48 pm
Location: Richmond, BC, Canada

Sat Jun 07, 2008 11:05 pm

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!
Last edited by n-strike on Sun Jun 08, 2008 1:40 am, edited 1 time in total.
User avatar
drex
Specialist
Specialist
Posts: 139
Joined: Mon Apr 21, 2008 4:00 pm

Sat Jun 07, 2008 11:17 pm

if you relly like math and gas laws, know the volume of your compressor and your chamber its possible but unpractical.
User avatar
starman
Sergeant Major
Sergeant Major
United States of America
Posts: 3027
Joined: Wed Dec 12, 2007 12:45 am
Location: Simpsonville, SC

Donating Members

Sat Jun 07, 2008 11:35 pm

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.
Last edited by starman on Sun Jun 08, 2008 12:44 pm, edited 1 time in total.
User avatar
n-strike
Specialist 2
Specialist 2
Posts: 219
Joined: Sat Apr 26, 2008 3:48 pm
Location: Richmond, BC, Canada

Sun Jun 08, 2008 1:41 am

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?
User avatar
DonTheLegend
Private 4
Private 4
Posts: 99
Joined: Fri Jan 06, 2006 6:32 pm

Sun Jun 08, 2008 1:56 am

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.
User avatar
starman
Sergeant Major
Sergeant Major
United States of America
Posts: 3027
Joined: Wed Dec 12, 2007 12:45 am
Location: Simpsonville, SC

Donating Members

Sun Jun 08, 2008 2:02 am

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.
Last edited by starman on Sun Jun 08, 2008 12:44 pm, edited 1 time in total.
THUNDERLORD
Sergeant 3
Sergeant 3
Posts: 1264
Joined: Fri Mar 28, 2008 1:42 pm

Sun Jun 08, 2008 2:16 am

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:
-----SPEED,STRENGTH, AND ACCURACY.-----
"Procrastination" is five syllables for "Sloth".
Theopia 8)
Born To Be Alive!
User avatar
kablooie
Specialist
Specialist
Posts: 188
Joined: Sun Feb 18, 2007 8:21 pm

Sun Jun 08, 2008 2:23 am

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).
User avatar
D_Hall
Staff Sergeant 5
Staff Sergeant 5
United States of America
Posts: 1914
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Has thanked: 7 times
Been thanked: 41 times

Donating Members

Sun Jun 08, 2008 12:33 pm

Personal opinion: If you can't afford pressure gauges, you can't afford this hobby.
Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
starman
Sergeant Major
Sergeant Major
United States of America
Posts: 3027
Joined: Wed Dec 12, 2007 12:45 am
Location: Simpsonville, SC

Donating Members

Sun Jun 08, 2008 1:02 pm

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.
User avatar
n-strike
Specialist 2
Specialist 2
Posts: 219
Joined: Sat Apr 26, 2008 3:48 pm
Location: Richmond, BC, Canada

Sun Jun 08, 2008 1:59 pm

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?
TurboSuper
Corporal 5
Corporal 5
Posts: 986
Joined: Thu Jun 16, 2005 1:44 pm
Been thanked: 1 time

Sun Jun 08, 2008 2:30 pm

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.
"If at first you dont succeed, then skydiving is not for you" - Darwin Awards
User avatar
n-strike
Specialist 2
Specialist 2
Posts: 219
Joined: Sat Apr 26, 2008 3:48 pm
Location: Richmond, BC, Canada

Sun Jun 08, 2008 2:47 pm

Haha, yeah...They do make it look a little cooler...
User avatar
DonTheLegend
Private 4
Private 4
Posts: 99
Joined: Fri Jan 06, 2006 6:32 pm

Sun Jun 08, 2008 4:52 pm

1/4" NPT requires a 7/16" drill bit
User avatar
psycix
Sergeant Major 4
Sergeant Major 4
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands

Donating Members

Sun Jun 08, 2008 6:48 pm

I recommend installing a gauge on your cannon. Pump gauges tend to give wrong values (usually too high).
Till the day I'm dieing, I'll keep them spuddies flying, 'cause I can!

Spudfiles steam group, join!
Post Reply