12 gram Co2 pressure gauge

[Darth]

I've always wanted to put a gauge on my 2240 (or whatever) but wasn't quite sure how to do it. I finally figured it out ...
I like the 12 gram cylinders just because they are so convenient. You can stick a few in your pocket if you needed to.
I keep this pressurized for the occasional "pest" that might invade my yard. Now, with the gauge, I can tell if I have any fuel left.

I bought a 1" 1200 PSI paintball gauge with 1/8 NPT threads, then I chucked it up in my lathe and turned it down to 1/4". After that I threaded it to 28 TPI. So now, I have a gauge with 1/4*28 threads.
That's just the perfect size to fit in the shoulder of the cap. The next step was to drill and tap the cap. I was going to use an O-ring at the bottom of the hole to seal the gauge but I forgot that I had bored out the cap to .600" deep. As you can see, I now have a boo-boo ... 

So, I figured I would try a little BLUE Loc-Tite on the threads and see if that holds. So far, it's good. If it does indeed leak over the long term I'll make a new one from a cap that has not been bored deeper.

It seems that when the pressure starts taking 50 PSI drops without recovery ... your all done. I got 19 shots (22 cal) ranging from 620 to 601 FPS (14.3 gr)and then the velocity started to nose dive.

[Trophyhunter49]

  Now that very interesting!! 

[mudduck48]

Now there is something you don't see every day. 

[ped]

whilst it looks different gauges on co2 are a bit of a waste of time ,as long as you have liquid co2 they'll read the same pressure(which will depend on temp)and won't show how much liquid co2 you have left and as you've found once the gauge drops your out of gas
Loctite lock and seal should seal it

[Darth]

... gauges on co2 are a bit of a waste of time

Up until now ... I've not found a way (other than this) to tell if there is pressure in this Co2 gun without shooting it ... am I missing something here ?
I am not THAT STRONG in the ways of the FORCE ...

My HPA has a gauge and ... if it has pressure ... it should shoot. If the pressure is depleted it will not.

... and won't show how much liquid co2 you have left

sure it does ... when the pressure does not recover ... you can pretty much bet you're out of liquid  ... right ?

Which for my purpose ... is all I need to know 

[ped]

fair do's mate if your happy and it fulfils your requirements that's all that matters

[mudduck48]

So, how much pressure is in a CO2 cart?

[ped]

all depends on temperature
https://www.google.co.uk/search?q=co2+pressure+chart&biw=1024&bih=644&tbm=isch&imgil=BnxVNKi8uLpCTM%253A%253BqxpJKXc4Z9bz3M%253Bhttp%25253A%25252F%25252Fwww.gatewaytoairguns.org%25252FGTA%25252Findex.php%25253Ftopic%2525253D20723.0&source=iu&pf=m&fir=BnxVNKi8uLpCTM%253A%252CqxpJKXc4Z9bz3M%252C_&usg=__73EmJkdEwKOCDgqZCtc7H9c52Y8%3D&dpr=1&ved=0ahUKEwiY5aW_pN3OAhXBshQKHQjZBQkQyjcIJw&ei=0kS_V5i0MMHlUoiyl0g#imgrc=BnxVNKi8uLpCTM%3A

[mudduck48]

Too much info. I heard tell, it was between 800 and 900psi depending on the air temp.

[CraigH]

The short answer is, around 850 psi in the 70 degree F area.  In a hot car the cartridge can get to 1500 psi.   

[Darth]

Here's a interesting thing ...

I took it to work with me, installed a new powerlet, charged it and left it in the car ... later in the day the gauge was pegged at over 1200 PSI ... it kinda looks like it could have been 1300 based on the line spacing.

It started out at about 900 this morning ... so, it went into the superfluid state while it was in the car I guess, based on some charts I've found. The car was about 110-115 degrees when I checked it.

So I'm even happier I installed it ... I can now see something I Kinda already knew ...
Actually, based on that chart, if I'm in the superfluid state I can tell about how much CO2 is left in the powerlet. If I'm reading the chart correctly.
Mr. Sterne knows all this stuff ... I'm just a novice.

And yes, I removed it from the car and brought it in to the air conditioning as soon as I saw that.

[KevinP]

COOL STUFF, I like it .....