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Posted: Sat Oct 27, 2012 7:44 pm
by archie370
Posting on this thread a bit late but i see everyones point its kind of sad really that eventually everyone has to grow up :( ... im young and just got into spudding, ive made a spud gun, personally i think there unsafe, for the ordinary spudder its very hard to predict what happens in combustion chambers ive you put to much gas it explodes like what happened to JSR yesterday. Pneumatics are simple yes but they are safer you can control what you put in them and how much to let out. Everyone has their speciality i guess people turn to Pneumatic guns instead of hybrid.

Posted: Sat Oct 27, 2012 7:58 pm
by MrCrowley
Pneumatics are simple yes but they are safer you can control what you put in them and how much to let out
archie370 wrote:in combustion chambers ive (sic) you put to much gas it explodes
for the ordinary spudder its very hard to predict what happens in combustion chambers
dafuq?
I don't think you know what you're talking about.

If you put too much fuel in a combustion, the fuel wont ignite. What happens inside a combustion is easy to predict if you know what you're doing; put in the right amount of fuel and you can be pretty sure it will ignite. I would say that with combustions, it is easier to control what goes in them and what comes out. You need less than 1PSI of propane in a typical combustion and even if you leave the propane tank valve open and your chamber equalises, you shouldn't be at any risk if your fittings are pressure rated.

Are you confusing the term combustion with hybrid? Even then, two out of three things you said don't make sense.

Posted: Sat Oct 27, 2012 9:52 pm
by Gippeto
So....what happened to Jack? Epoxy shard in the arse? Must have missed it.

Posted: Sat Oct 27, 2012 9:52 pm
by PVC Arsenal 17
Fnord wrote: We need to start reverse-engineering the tippman C3.
I've been fiddling with combustion repeaters for a year and a half.

Just never bothered to post I guess...

Posted: Sun Oct 28, 2012 1:05 am
by archie370
sorry i was never really good at english :) ... pneumatics and no doubt safer than hybrids, whoever challenges it, clearly shouldn't be spudding.

Posted: Sun Oct 28, 2012 1:06 am
by jackssmirkingrevenge
archie370 wrote:it explodes like what happened to JSR yesterday.
If you're talking aboutthis, it didn't happen to me.

Well it did, but a long time ago, with something smaller: http://www.spudfiles.com/forums/mini-hy ... 21645.html
Pneumatics are simple yes but they are safer you can control what you put in them and how much to let out. Everyone has their speciality i guess people turn to Pneumatic guns instead of hybrid.
If you put 500 psi of air in that PVC chamber, it would have blown up just the same. All launchers are dangerous if made improperly, whether they burn gas or not.

Posted: Sun Oct 28, 2012 2:08 am
by Zeus
PVC, please do post it, I've got a business proposition, and it'd potentially make the organisation more profit, which helps all the Australians here.

Posted: Sun Oct 28, 2012 2:35 am
by archie370
"If you put 500 psi of air in that PVC chamber, it would have blown up just the same. All launchers are dangerous if made improperly, whether they burn gas or not."

yeah of course, 500psi would blow up but at least you know exactly how much you put in, Combustion explodes creating a chain reaction with all the other molecules of gas, therefore creating heat then those molecules increase creating pressure which is probably incalculable for most spudders,

BTW i thought it happened just the other day :), maybe i read the post wrong :) but it still exploded...

Does anyone else agree that pneumatic guns are safer than Hybrid, because i do...

Posted: Sun Oct 28, 2012 3:06 am
by MrCrowley
500psi would blow up but at least you know exactly how much you put in
So what? How is that helpful if you're dead? Knowing how much pressure you put in a failed cannon isn't of much help at all in this scenario.
Combustion explodes creating a chain reaction with all the other molecules of gas, therefore creating heat then those molecules increase creating pressure which is probably incalculable for most spudders
The pressure that results from igniting a 1x stoichiometric mix of propane in a chamber is generally known to spudders and has been known for awhile. I can't remember the exact specifics, but I believe you can expect around 80-120PSI generated with ~120PSI being close to the theoretical maximum in spudding circumstances. Regardless of whatever the real numbers are, we know that they're not going to get to a dangerous level for most pressure rated cannons.

You seem to think that fuel has a mind of its own and, if it decided to, it can generate extreme pressures for no reasons obvious to the person who built the cannon. These fuels obey the laws of science; a certain fuel can only do so much in particular circumstances and we can rely on the fuel to behave in a way we would expect. We're not just injecting fuel and hoping it doesn't generate 500PSI and blow the cannon up, we know what we are doing. Anyone who spends just a little bit of time on this forum will come to realise that. Anyone who sprays too much fuel in their cannon and finds out why it wont ignite will also come to realise that.

but it still exploded...
So what? I've seen pneumatics fail.
Does anyone else agree that pneumatic guns are safer than Hybrid, because i do...
First of all, opinions don't count for much. Secondly, it's not like anyone is debating this seriously. There's no real right or wrong answer. It's mostly a useless question.

However, the real answer is: it depends. It depends how both cannons are constructed. A 2x mix hybrid using the appropriate galvanised iron fittings is probably a lot safer than a 120PSI pneumatic using pressure rated PVC fittings. You can't really thread galv. iron fittings so badly that they will come apart, but it's quite easy to screw up the solvent welding of PVC pipe and fittings. Furthermore, you can probably drop the iron fittings all you want, and use them safely during winter. PVC, on the other hand, has a habit of shattering if you drop it from even only a foot or so and doesn't handle the cold very well.

You ask the wrong questions, make wild assumptions and then draw spurious conclusions. You can't make generalisations about combustion, pneumatic or hybrid cannons because there are far too many variables to consider.

Just remember, it doesn't matter what anyone thinks about which is safer. What matters is that you know what you're doing. Someone saying pneumatics are safer than hybrids wont make it less likely for a pneumatic cannon to fail.

Posted: Sun Oct 28, 2012 4:28 am
by archie370
Simple my conclusion is people choose pneumatic guns because they are somewhat safer that is why Hybrids are not as popular as they used to be :), not denying they are alot of fun and they are safe to a certain standard.

"stoichiometric" is a good way to measure how much gas to use but wheather we like it or not accidentally put that little bit more of gas in the combustion chamber and boom :)

No one is fighting, this thread is for opinions on why pneumatics are more common :)

Posted: Sun Oct 28, 2012 4:36 am
by MrCrowley
archie370 wrote:Simple my conclusion is people choose pneumatic guns because they are somewhat safer that is why Hybrids are not as popular as they used to be :), not denying they are alot of fun and they are safe to a certain standard.
Ah, you're still referring to the original topic at hand. I was simply referring to safety; not why one is more popular than the other.
archie370 wrote: "stoichiometric" is a good way to measure how much gas to use but wheather we like it or not accidentally put that little bit more of gas in the combustion chamber and boom :)
That is simply wrong. If you do that, the mix will be off and it wont ignite.

You can do your own experiment to test your hypothesis: purge a combustion cannon chamber of air and fill it completely with propane. Good luck getting ignition (you wont).

Posted: Sun Oct 28, 2012 5:12 am
by archie370
Stick a bit of thermite in there that ll get it going :) probably melt my launcher into molton metal but i reakon it would ignite :)

Posted: Sun Oct 28, 2012 5:57 am
by Zeus
Mate, stop posting, you're digging yourself into a hole, and you'll just look like a fuckwit.

Hybrids made from standard steel fittings aee safer than a pneumatic running at the same post ignition pressure, the pipe sees the pressure for a smaller window of time. The same goes for combustions made from PVC.

And thermite igniting? Really?

Posted: Sun Oct 28, 2012 4:22 pm
by archie370
Yeah bud that was a shitty joke ....

Posted: Sun Oct 28, 2012 6:26 pm
by velocity3x
archie370 wrote:Does anyone else agree that pneumatic guns are safer than Hybrid, because i do...
I don't know....I'm not from around here.