my little air cannon

[stevenarroyo]

i made this little air cannon just because i had the parts to make it.
am planing in painting it soon.

it was a 17" long 3/4" barrel
a 3/4" ball valve
a 1 1/2" 1' long air camber

[starman]

............... **cricket chirp**................


Sounds like a nifty little gun.....some accompanying pictures would be very helpful.

[stevenarroyo]

http://i217.photobucket.com/albums/cc21 ... G00052.jpg

here is a picture of my cannon

[starman]

http://i217.photobucket.com/albums/cc21 ... G00052.jpg

here is a picture of my cannon

That's better. If you put the Img tags around the link, the picture will show up by default.

Like this...

[koolaidman]

that coupler looks like it's dvw.

[stevenarroyo]

o ok thanks starman!!

koolaidman whats a DVW??

[blind909]

Drain Waste Vent. Not Meant for pressure, and can fail at as low as 2 psi. You should replace it with a coupler that says NSF-PW XXX PSI @ 70* F

[stevenarroyo]

WTF 2psi!!!!

i never go past 65psi so whatever
i made that cannon because i had the parts and was bored.

i made a bigger 1 that i'll be putting up soon.

[BC Pneumatics]

Stevenarroyo,

Koolaidman is correct, that coupler is DWV and is not suitable for use on a pneumatic cannon. While many people use DWV fittings on combustions, pneumatics have to hold their pressure for an extended period of time. This means there is a chance for the launcher to be impacted or jolted while under pressure. Knocking around a charged pneumatic is incredibly dangerous and adding DWV into that picture is idiotic to say the least.

Also, while 2psi is a bit ridiculous (a failure at the pressure would do nothing but startle a butterfly anyway) blind909 is correct to sway you from using a DWV pneumatic. You do need to replace it with a pressure rated coupler, one that says NSF-pw. (I have never seen fittings that actually bare a numerical pressure value.)

We also advise against installing fill valves (or anything for that matter) into the rear of an end cap. This part of the cannon is more prone to failure than others, and anything that is tapped into a chamber should be placed where a fitting overlaps a pipe, thus creating a 'double thickness'. Not only will this improve the structural integrity of the launcher, it will reduce the chance of the fitting blowing out. (One thickness doesn't provide as many threads as one should have.)

Luckily it looks like you have enough pipe to cut out the DWV coupler and the bushing, and replace them with a safe assembly. That is what needs to be done before you use this cannon again.

My attention is also drawn to the fact that your launcher lacks the typical purple stains left from a prime job. Since this was made from 'parts laying around', I am going on the assumption that you did not have a can of hard-to-find clear primer. This is particularly likely since clear primer is actually a pain to use on anything where aesthetics is not an issue. (IE, practically every application PVC pipe is used for.)

With that being said, it is lucky that you have built another, as this launcher seems to be very unsafe, and should be retired without another shot ever passing through it.

Your "I never go past 65psi so whatever." comment was not only ignorant, it was down right disrespectful to the people who are trying to help you. At 8:42 AM you did not know what DWV was, and by 9:32 AM you were posting saying it was okay to use a DWV part at 65psi.

I hope your new launcher is safer than this one.

[stevenarroyo]

i did use clear primer

and am srry for sounding like an ass to every1.

[nivekatoz]

I agree with you 100% BC PNEUMATICS.. and STEVENARROYO don't sweat.......... it its cool... :salute:

[stevenarroyo]

alright thanks man

am new to this place so if any1 knows how to do things can plz help me

[nivekatoz]

STEVENARROYO ..Im layed back about $hit, but alot of people are kinda jerks about stuff..You just have to take the good with the bad..Every body has there own way of thinking..

[BC Pneumatics]

One thing that most of us like is proper English and grammatically correct sentences. A little proof reading goes a long way, and apps with built in spell checkers are becoming the norm. If you put more effort into your writing, you will get a much better experience around here.

[stevenarroyo]

ya i know
just like some ppl can be dicks and other can be nice and help others