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What is safer?

Posted: Sun Jul 30, 2006 9:31 pm
by spud man
Which is safer, a Pnumatic Cannon pumped up to 50 psi and above or a Combustion Cannon using metered propane?

Posted: Sun Jul 30, 2006 9:39 pm
by SpudStuff
Ahh that is the worst question I have ever heard. Let me translate that to english for you.

Which is safer, a Pnumatic Cannon or a Combustion Cannon using metered propane?

Now is that what you mean.


The answer to your question is it depends on your skill. Have you ever built a spudgun before?

Posted: Sun Jul 30, 2006 9:42 pm
by spud man
Yes i did build a spud gun befor

Posted: Sun Jul 30, 2006 9:47 pm
by SpudStuff
Okay and what kind did you build little boy.

Posted: Sun Jul 30, 2006 9:49 pm
by CS
Safer in which regards? You cant just cant throw out there such a broad question and get a golden answer.

If your pumping your pneumatic to over ~50PSI, it is more prone to fail by over compression.

Posted: Sun Jul 30, 2006 9:50 pm
by spud man
I built a combustion cannon

Posted: Sun Jul 30, 2006 9:58 pm
by SpudStuff
Yes that is a good way to put it Pimp. A pnumatic takes more skill and money to make than a basic combustion. A propane meter is going to be the big ticket in the cost factor. And contrary to popular belief, propane meters make cannons safer because you always have a good shot and no misfires that make you vent the fuel from the cannon.

Posted: Sun Jul 30, 2006 10:00 pm
by SpudStuff
And he edited hes post to cover up his stupidity.

Posted: Sun Jul 30, 2006 10:01 pm
by spud man
A combustion cannon only puts out a max 30 to 35 psi right

Posted: Sun Jul 30, 2006 10:48 pm
by carlbelcher
A combustion with propane metering can produce up to 70psi.

EDIT:

Retraced unessicary comment.

Posted: Sun Jul 30, 2006 10:50 pm
by Velocity
The estimated Peak Combustion Pressure for each atmospheric mix of propane/air is 102psig.
This is what DR said from the spudtech forums. But that is only for a short span of time under ideal conditions; 30-35 psi is basically the max pressure that you need to worry about

Why is it that lately everyone is being such a friggin jerk? Spudstuff, you dont need to flip out everytime a newb posts a seemingly unresearched/unintelligent question! JUST LEAVE IT ALONE! I feel like i have said this about 1000 times in the past two days on this forum and on the spudtech forum. Is he somehow insulting you? Or are you just some insecure spaz who only enjoys putting down new members who won't fight back :x ?! [/b]

Posted: Sun Jul 30, 2006 11:36 pm
by M3NT4L
Pneumatic cannons are safer just make sure that it is airtight, sch 40 pressure rated (EVERY PART) and that you have a psi gauge. Please if you arent sure of the ability of your cannon or arent confident in your craftsmanship do not go over 65-70 psi.

Posted: Sun Jul 30, 2006 11:45 pm
by carlbelcher
Why do you think pneumatics are safer? maybe it's the higher pressure... or the higher skill level required to make one... well neither one of those could be it M3NT4L why don't you enlighten me...

Posted: Mon Jul 31, 2006 6:32 am
by mark.f
Combustions are usually a safer first build. Take me, for example. My first pneumatic had a DWV reducing coupling to get from 3" to 1.5", a rubber schrader installed through only one layer of PVC, and a pressure gauge from a car emergency compressor just screwed into a hole only marginally smaller than the threads and then epoxied into place.

It lasted until I took a hacksaw to it after I realized the mistakes I've made.

After I finish my next project, I'm deciding to either build a pneumatic or a hybrid. Whichever one seems to float my boat at the time...

Posted: Mon Jul 31, 2006 8:27 am
by Mihlrad
Lol, for a retarded pyromanica like myself, combustion is not safer. When i was trying to get my first BBQ ignitor to work, it wouldnt go off so i opened the gun, and pushed it. Well needless to say, i lost my eyebrows and my hairline receded an inch that day.