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| dinsdale |
 Posted: 08/27/2006 19:06 PM Post subject: abs pressures |
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Sergeant
Joined: 27 Aug 2006
Posts: 91
166.66 Spud Bux
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i have just read on a forum here that pvc should be used for pneumatic cannons and not abs since it isn't pressure rated.
does anyone have comparitive info on the burst point of ABS vs PVC?
i just built a pneumatic cannon from ABS, it's 2 " ID, for both the chamber and barrel, and both are 36" long. it is an inline cannon with an orbit watermaster valve (not modded yet) i've been launching all kinds of stuff at 95 psi. I would much rather have a piece of ABS bulge and rupture, than a piece of PVC grenading on me. I'd like to hear the opinion of an air cannon veteran on the matter.
BTW my cannon is very ugly and hillbillyish so i didnt feel the need to post pics |
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| Velocity |
| Posted: 08/27/2006 20:27 PM Post subject: |
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Brigadier General
Joined: 07 Feb 2006
Posts: 948
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A well-constructed PVC pneumatic will NOT blow; thats why I use it. Sure, if you made two cannons, one of cell-core PVC and one of ABS, i'd use the ABS; you are correct in wanting to be closer to an ABS rupture than a PVC explosion.
The problem is, an ABS cannon cannot hold the sustained pressure, and therefore, over time, will undoubtedly fail at some point (considering you take it up to 95 PSI). A well-constructed PVC cannon will not explode unless used: A) above a safe pressure (generally 100 PSI, +/- for smaller/larger bore cannons, respectively); B) in an extremely cold or hot environment; C) in any stupid, non-common-sense-using manner.
PS: wrong section to post in |
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| dinsdale |
| Posted: 08/27/2006 21:27 PM Post subject: |
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Sergeant
Joined: 27 Aug 2006
Posts: 91
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thanks, i realized as soon as i posted i was in wrong spot.
one other example of why i like abs is if you take a piece of abs and a piece of pvc of equal size and attempt to destroy it (eg with a sledgehammer, or crushing in a vise) it takes substantially more to break the abs |
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| dinsdale |
| Posted: 09/02/2006 17:45 PM Post subject: |
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Sergeant
Joined: 27 Aug 2006
Posts: 91
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| I have done more testing with my abs gun and found it can keep shooting at 95-110 psi without failure, it has had probably 100 shots through it and i plan on testing with higher pressure just so that i can share the results |
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| drac |
| Posted: 09/02/2006 17:58 PM Post subject: |
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Metalhead Moderator
Joined: 24 Apr 2005
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You most likely have the rare, pressure rated version of ABS that isn't cellcore. It's generally harder to come by and more expensive, but I would prefer that over PVC.
But since I can't find pressure rated ABS for crap, I have to stick with PVC. |
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| cannon freak |
| Posted: 09/02/2006 18:03 PM Post subject: |
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1st Lieutenant
Joined: 12 May 2006
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| Are there any pressure ratings on the ABS pipe? Where did you get it? |
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| dinsdale |
| Posted: 09/02/2006 18:03 PM Post subject: |
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Sergeant
Joined: 27 Aug 2006
Posts: 91
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actually it was more than twice the price of non-pressure ratec pvc, and is thick walled.
it didn't appear to be cell cored when i cut and drilled it.
on the side it says abs-dee-dwv t1g2
edit: no pressure rating, got it at a home depot
Last edited by dinsdale on 09/02/2006 18:04 PM; edited 1 time in total |
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| SpudStuff |
| Posted: 09/02/2006 18:03 PM Post subject: |
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Major General
Joined: 10 Dec 2005
Posts: 1379
128.17 Spud Bux
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| Pressure rated ABS is an oxy-moron |
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| drac |
| Posted: 09/02/2006 18:07 PM Post subject: |
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Metalhead Moderator
Joined: 24 Apr 2005
Posts: 890
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| SpudStuff wrote: | | Pressure rated ABS is an oxy-moron |
No it's not. There actually is a pressure rated type of ABS, it's just extremely rare. Why don't you google it before using fancy english terms on us.   |
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| dinsdale |
| Posted: 09/03/2006 19:33 PM Post subject: |
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Sergeant
Joined: 27 Aug 2006
Posts: 91
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well i've now had my non-rated abs cannon past 125 psi without failure, hopefully i'll have higher figures tomorrow  |
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| dinsdale |
| Posted: 09/04/2006 16:24 PM Post subject: |
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Sergeant
Joined: 27 Aug 2006
Posts: 91
166.66 Spud Bux
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I've just went through a bag of potatoes at 155 psi in my non rated everyday abs sprinkler valve cannon (the valve is rated at 80 psi) so far no failures, next test 170 psi
edit, ps i modded the valve before crossing 120 |
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