Special Ops Paintball: never ever EVER made a homemade law - Special Ops Paintball

Jump to content


  • (7 Pages)
  • +
  • « First
  • 4
  • 5
  • 6
  • 7
  • You cannot start a new topic
  • You cannot reply to this topic

never ever EVER made a homemade law i could have died

#76 User is offline   Florentine 

  • Group: Banned
  • PipPipPipPipPipPipPip
  • Group: Members
  • Posts: 6,356
  • Joined: 27-December 06
  • Gender:Male
  • Location:Pennsylvania

Posted 19 April 2008 - 06:19 AM

View PostMarauder_Pilot, on Apr 18 2008, 11:13 PM, said:

I dunno, the whole issue could have been totally prevented by Florentine spending $15 on a blowout valve and a threaded tap tool. And you can't get any safer then a pressure chamber that is physically incapable of holding more then the popout valve's rating. You don't even *need* a reg for that setup, but I'd still never go without because it's a) a nice backup and :) Stops you from wasting gas as the popout expels anything extra.

well, see, i didn't know about those, i didn't think i needed one. but what about a 3" diameter pipe? oh, and you guys calculations are off, the outside diameter is 1 1/2", the inside is much smaller. so that highers the pressure
Hey baby, wanna come over to myspace so i can twitter your yahoo till I google all over your facebook?
Feedback

Becc: "I'm not really a vegetarian, I eat some forms of sausage."
0

#77 User is offline   Texas Trigger 

  • Nothin' but the rain...
  • PipPipPipPipPip
  • Group: Members
  • Posts: 2,064
  • Joined: 15-November 04
  • Gender:Male
  • Location:USAF Academy, CO

Posted 19 April 2008 - 12:21 PM

I had a PVC launcher explode on me once. From then on, I built all my launchers out of galvanized steel.
I'm here, Benjie, I'm here, I said, clasping his hand on my arm.
Help me Rootie, my legs won't move.
Aw Benjie, it'll be okay Benj, I'll give you mine

USAFA '12.
0

#78 User is offline   drake 

  • chucho el roto
  • Pip
  • Group: Members
  • Posts: 32
  • Joined: 16-February 05
  • Gender:Male
  • Location:Cooper City ,Florida
  • Brigade Name:SWAMP TING

Posted 19 April 2008 - 04:01 PM

Brigade central ,senario positions , launcher guide , and I added pressure regulator from my air source (Compressed air ) glad your ok
user posted image
0

#79 User is offline   thebostinian 

  • SOFA Favorite Member Title 2009
  • PipPipPipPipPip
  • Group: Members
  • Posts: 1,268
  • Joined: 08-May 07
  • Gender:Male
  • Location:Grove City College or Burnt Hills, NY
  • Brigade Name:thebostinian

Posted 19 April 2008 - 04:23 PM

View Postflorentine, on Apr 19 2008, 09:19 AM, said:

View PostMarauder_Pilot, on Apr 18 2008, 11:13 PM, said:

I dunno, the whole issue could have been totally prevented by Florentine spending $15 on a blowout valve and a threaded tap tool. And you can't get any safer then a pressure chamber that is physically incapable of holding more then the popout valve's rating. You don't even *need* a reg for that setup, but I'd still never go without because it's a) a nice backup and :wacko: Stops you from wasting gas as the popout expels anything extra.

well, see, i didn't know about those, i didn't think i needed one. but what about a 3" diameter pipe? oh, and you guys calculations are off, the outside diameter is 1 1/2", the inside is much smaller. so that highers the pressure

you mean "raises?"

most PVC pipe has a wall thickness of about 1/8"-3/16"...so the cross-section of the pipe is between .009 and .007 square feet, compared to .013 square feet. over a two foot long chamber, that decreases the volume from .026 cubic feet to .018-.014 cubic feet (let's call it .016 cubic feet, the average of the two estimates). that decreases the volume almost 50%.

obviously, it doesn't make as much of a difference with larger diameters, but 1 1/2" PVC piping doesn't really make sense when making a air cannon powered by a compressed gas of any kind. 3" pipe has a cross section of approximately .041-.037 square feet, and a volume of .082-.074 cubic feet - about 4-5 times that of the 1 1/2" pipe, accounting for the wall thickness of each.

<EDIT>
i really screwed up my math the first time i tried this.

This post has been edited by thebostinian: 19 April 2008 - 04:34 PM


"Yeah, but a thread that started out as borderline weird and creepy to begin with has now taken a left turn into 'Deliverance." - Violator
Don't try to pronounce the second "o". Instead, try realize the truth: there is no second "o"
0

#80 User is offline   splntercell 

  • Sophomore Member
  • PipPipPip
  • Group: Members
  • Posts: 337
  • Joined: 03-April 07
  • Brigade Name:splntercell

Posted 21 April 2008 - 03:50 PM

Here is one of the websites i get info from about building laws. Doom labs . This link will take you directly to his formula for figuring out how big an expansion chamber you need to lower the psi of a 12 gram. Me personaly i would never put co2 into pvc. If i build a launcher to use 12 grams i would build the expansion chamber out of galvanized pipe. If you use hpa with a regulator and a safty pop vaulve you can build a very safe launcher. My latest launcher uses a 2" x 16" pvc expansion chamber and can reach 100 yards easily at 80 psi.
0

#81 User is offline   Hatchet 

  • Certified Pump-Ninja
  • PipPipPipPip
  • Group: Members
  • Posts: 780
  • Joined: 12-November 06
  • Location:Chas, WV
  • Brigade Name:Hatchet88

Posted 24 April 2008 - 09:02 AM

Florentine....they're completely safe if you have an idea of what you're doing, which, no offense, you didn't. 12grams are under extreme pressure, and a CO2 tank outputs around 1100 or so psi, IIRC. Pipe that is pressure rated to 350 cannot be expected to hold that kind of pressure for long. It wasn't the 12gram that blew the rig, it was the pressure of the CO2 in the underrated pipe. Next time, get a regulator with a gauge and regulate the pressure down, and build a chamber with a pop vavle on it, so that just in case you do over-fill the launcher, it'll be the valve that blows and not the whole rig.
The signature in this location has been removed due to FORUM RULES VIOLATIONS. Please check this link : FORUM SIGNATURE RULES AND REGS and feel free to repost your signature according to the guidelines set by this forum.

^I think I'll just leave it that way. It suits me.
0

#82 User is offline   DROP THE HAMMER 

  • Forum Member
  • PipPip
  • Group: Members
  • Posts: 136
  • Joined: 27-February 08

Posted 24 April 2008 - 05:47 PM

wow, i guess your lucky it didnt decide to blow with the 9oz. on. this is crazy, im still trying to picture what happened.
0

#83 User is offline   Florentine 

  • Group: Banned
  • PipPipPipPipPipPipPip
  • Group: Members
  • Posts: 6,356
  • Joined: 27-December 06
  • Gender:Male
  • Location:Pennsylvania

Posted 24 April 2008 - 07:04 PM

i did not dump the 9 ounce in the whole thing. and the 12 grams pressure was dropped down to 260 psi as the physic majors say.
Hey baby, wanna come over to myspace so i can twitter your yahoo till I google all over your facebook?
Feedback

Becc: "I'm not really a vegetarian, I eat some forms of sausage."
0

#84 User is offline   Hatchet 

  • Certified Pump-Ninja
  • PipPipPipPip
  • Group: Members
  • Posts: 780
  • Joined: 12-November 06
  • Location:Chas, WV
  • Brigade Name:Hatchet88

Posted 25 April 2008 - 09:33 AM

Florentine, the pressure MAY have been 260 at one point...but you didn't have any means to keep it there. CO2 expands. And I haven't seen much physics flying around in here; there's been a lot of chemistry though. Didn't really fit the situation, but boyle's and the ideal gas law = chemistry.

Just do us all a favor and pretend LAWS don't exist, or learn from your mistakes and do it better next time. In the end though, glad you're not hurt.
The signature in this location has been removed due to FORUM RULES VIOLATIONS. Please check this link : FORUM SIGNATURE RULES AND REGS and feel free to repost your signature according to the guidelines set by this forum.

^I think I'll just leave it that way. It suits me.
0

#85 User is offline   cookie 

  • Senior Member
  • PipPipPipPipPip
  • Group: Members
  • Posts: 1,632
  • Joined: 28-November 06
  • Brigade Name:Cookie

Posted 27 April 2008 - 08:29 PM

2" x 24" thick wall PVC chamber
2" x 24" thick wall PVC barrel
2" piston valve
HPA tank
two stages after the HPA, each with regulator and safety valve
40 PSI regulated input
RESULT: Just over 195 to 200 fps (about 420 fps with 125 psi)

Cannon I built reaches 215 fps with 31 psi (bigger chamber and longer barrel though)

This post has been edited by cookie: 27 April 2008 - 08:30 PM

COOKIE
BAD MONKEYS
Team Cook
Armor Commander
Eunach Engineer
Minister of Internet Harassment
0

#86 User is offline   Death Envoy 

  • Nos Mos Nunquam Intereo
  • PipPip
  • Group: Members
  • Posts: 150
  • Joined: 14-August 08
  • Gender:Male
  • Location:Ohio, USA
  • Brigade Name:Death Envoy

Posted 26 January 2009 - 10:23 PM

Ok, first off, its a good thing we built these in Physics as a project (well, a mortar, but the same concept). Luckily, we didn't have the same experience as Florentine.

But seriously, Florentine, I want to see the damage. Why no pictures?
0

#87 User is offline   5N1P3R 

  • Master Member
  • PipPipPipPipPipPip
  • Group: Members
  • Posts: 2,832
  • Joined: 24-August 08
  • Gender:Male
  • Location:Minnesota

Posted 27 January 2009 - 03:54 PM

View PostDeath Envoy, on Jan 26 2009, 11:23 PM, said:

Ok, first off, its a good thing we built these in Physics as a project (well, a mortar, but the same concept). Luckily, we didn't have the same experience as Florentine.

But seriously, Florentine, I want to see the damage. Why no pictures?


Do you realize the last time someone replied to this thread was in April!
0

#88 User is offline   The Bear 

  • The Bear
  • PipPip
  • Group: Members
  • Posts: 205
  • Joined: 10-January 08
  • Gender:Male
  • Location:NY
  • Brigade Name:Ghost Bear

Posted 27 January 2009 - 04:57 PM

:aah: Necropost!! Oh no!

But as long as it's been bumped, anyone know if they make HDPE in a high enough pressure rating? That would be great for LAWs because it doesn't fragment and shatter like PVC, it deforms and tears. It's what we use for aerial mortars so if a lift charge fails or a shell is loaded upside down there won't be shrapnel thrown like a grenade when the burst charge goes. It simply balloons out and literally tears a rip down the side of the pipe.

But again, I don't know if it comes in a high enough pressure rating. And in smaller diameters especially any lenght over a couple feet is fairly non-rigid making it bad for barrels. But for an expansion chamber it could be a safe way to go...

Bear
Posted Image
Posted Image
Posted Image
0

#89 User is offline   buffaloclone 

  • Sophomore Member
  • PipPipPip
  • Group: Members
  • Posts: 438
  • Joined: 21-October 06
  • Gender:Male
  • Location:the getto

Posted 27 January 2009 - 06:31 PM

you did it wrong. you need a pressure gauge and you shoulder use PVC. their is another type pf pipe (AVC or something, its black) for things like this. its rated for higher pressure and wont explode. if it bursts it will only rip a gash in the pipe no pieces will fly off. and you also gotta make sure you dont screw the fittings in to the pipe. their has to be a nut on the other side. also their should be an adjustable regulator in between the gas source and the chamber. that way you know it is allways under the right pressure and you can get one for as little as $20 on sale
0

#90 User is offline   Florentine 

  • Group: Banned
  • PipPipPipPipPipPipPip
  • Group: Members
  • Posts: 6,356
  • Joined: 27-December 06
  • Gender:Male
  • Location:Pennsylvania

Posted 27 January 2009 - 07:54 PM

View PostDeath Envoy, on Jan 27 2009, 12:23 AM, said:

But seriously, Florentine, I want to see the damage. Why no pictures?

Maybe because this is from April, and its now January.
Hey baby, wanna come over to myspace so i can twitter your yahoo till I google all over your facebook?
Feedback

Becc: "I'm not really a vegetarian, I eat some forms of sausage."
0

Share this topic:


  • (7 Pages)
  • +
  • « First
  • 4
  • 5
  • 6
  • 7
  • You cannot start a new topic
  • You cannot reply to this topic

2 User(s) are reading this topic
0 members, 2 guests, 0 anonymous users