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PVC vs. ABS for pnuematic cannon.
Posted: Sun Aug 26, 2007 4:26 pm
by ALIHISGREAT
which should i use... i read somewhere that pvc is unsuitable for compressed air systems (has anyone had problems with it?), but ABS is super expensive and hard to get.
Posted: Sun Aug 26, 2007 4:33 pm
by Hubb
Not being rude, but wasn't that question answered in your other thread?
No. I have never had any problems putting compressed air into PVC (pw) pipe. Just don't go over the rating on the pipe.
Posted: Sun Aug 26, 2007 4:41 pm
by iknowmy3tables
pvc is said not to be safe because in the case that it does burst it will create shrapnel but it almost never burst cause people usually operate them much lower than the rated pressure and much lower that the burst pressure, ABS is dangerous when dwv type is used but with pressure rated ABS it is actually safe according to manufactures to use for compressed air
Posted: Sun Aug 26, 2007 4:53 pm
by ALIHISGREAT
yer i was just wondering if anyone had had any problems with pvc but i can't find any istances so im just gonna go ahead and use it, abs is a hassle, unless i can find a site stocking 3/4" abs in the uk
Posted: Sun Aug 26, 2007 4:53 pm
by Fnord
PVC is better overall for pneumatics. It does fail rarely, but when it does it is usually because of a defect in the pipe. I've only heard of 3 or 4 times that pressure rated pvc has failed below its operating pressure, and I don't think anyone was hurt.
I don't recall seeing an abs gun blow up, but that's probably because hardly no one builds them. A few abs combustions have failed, and combustions generally produce about 50-70 psi with metered propane.
For the size of the gun you are making, normal pvc is fine. If you plan on using something better than a sprinkler valve, you could use metal pipe to extend the pressure range you can work with.
Edit: vv Yes, I meant abs pneumatics.
Posted: Sun Aug 26, 2007 5:15 pm
by frankrede
Thats really not realistic fnord.
I see abs combustions all the time, on this site and others.
Posted: Sun Aug 26, 2007 5:19 pm
by ALIHISGREAT
frankrede wrote:Thats really not realistic fnord.
I see abs combustions all the time, on this site and others.
he means for pneumatics i think
Posted: Sun Aug 26, 2007 5:42 pm
by Hotwired
Posted: Sun Aug 26, 2007 5:58 pm
by ALIHISGREAT
i know but i want 3m length because for my cannon i am going to have a 2" chamber and the rest of the cannon will be 3/4" cause i want to shoot paint balls and pipestock only have 6m
Posted: Sun Aug 26, 2007 6:43 pm
by frankrede
order extra then.
Ever heard of a hack saw?
aww how cute!
http://www.pipestock.com/ABS_Pipe_Fitti ... eaded_160/
lol.but seriously, this would be cool for any uk spudguns with piston valves,
Posted: Sun Aug 26, 2007 6:47 pm
by origin unknown
Don't worry about it, just use PVC. Make sure you don't take your gun to too high pressures though, and don't leave it in the sun because UV light damages PVC. Another don't is shooting it in cold weather; it makes PVC brittle.
Posted: Sun Aug 26, 2007 7:18 pm
by ALIHISGREAT
its just a waste of money buying pipe you dont need
Posted: Sun Aug 26, 2007 7:32 pm
by Gepard
Beggars can't be choosers......
Posted: Sun Aug 26, 2007 8:45 pm
by frankrede
ALIHISGREAT wrote: its just a waste of money buying pipe you dont need
No its not.
I mean come on, have some extra icase of mistakes or future projects.
Posted: Sun Aug 26, 2007 8:49 pm
by mopherman
ALIHISGREAT wrote: its just a waste of money buying pipe you dont need
not true. i use every inch of all the pipe that i buy sooner or later. just buy 10 feet and you will have extra.