SpudFiles

Hello!

I am brand new out of the showroom on the forum I have a question regarding Pneumatic Potato Guns. I called every single hardware shop in the city (Canadian Tire, Home Depot, Home Hardware etc...) and NO Store, really NONE has some PVC SCH40 pipes.

So now, I want to know if I can use ABS pipes instead... and is there a special kind of ABS pipes to use (like in PVC, the SCH40 rated).

Thank you very much!
Dom

*SHIT this is in the wrong section. Can a moderator or admin move this topic in the right section please? Thank you very much *

Whiel ABS is acceptable (or even prefered) for combustion cannons, its a very bad idea to use on pneumatic guns. It's not pressure rated, and can't handle repeated pressurization. You need Sch40 or 80 PVC. If you can't get it locally, order it online. You could build a nice combustion gun out of ABS, though.

Peace,
Pete Zaria.

Yeah, ABS is out of the question for pneumatic launchers. I suggest you find a supplier of metal pipe fittings, and build a smaller pneumatic gun; check out Brian the Brain's shotguns (those are fairly advanced however)

Combustion gun is loud, and dangerous.

Ordering online is unfortunatly not a possibility for me

As for the Combustion Potato Gun, it doesnt need to PVC SCH40? Just normal PVC? (as long as its not DWV) or ABS?

Dom a combustion cannon can be made out of ABS, I'm using it and have had no troubles, I wouldn't use non rated PVC from any of the hardware stores since they are probable not much stronger than ABS in the first place and the failure characteristics of ABS are much better. If you really want to make it out of SCH 40 Pressure Rated PVC you could almost certainly buy it locally, since you have a Canadian Tire near you I am assuming that you live in Canada and it is hard to find the pipe trust me, it took me and my friend like a week searching through the yellow pages to finally find a place but even then the PVC was extremely expensive, so go with ABS.

"Combustion gun is loud, and dangerous."
Yes they are normally loud but you can make it quieter and they are less dangerous than a pneumatic, pneumatics are usually pumped to 100psi or more which is normally far far away from what a combustion cannon can produce.

Do you have any how-to to make it quieter? Noise is REALLY an issue. I live in Ottawa, quite near the Aviation Museum , quite near Sussex Drive also. A guy nearby had a combustion once and it made an horrible sound. RCMP was all over the place.

Well you can always make your gun have a really long barrel, say you have a propane combustion cannon. The ideal ratio is 0.8:1 for the most power, now you could make a gun have a ratio of 0.6:1 or lower and I bet that that would get rid of a lot of the noise issue, now this would however decrease the power of the gun, but you could always make a bigger gun if you don't have enough power.

You should hear my gun it has a 3:1 ratio and it makes quite a BANG!!!!

0.6:1... that would mean the Barrel diameter would be bigger than the chamber diameter right? Wouldnt that be a power issue?

So... if I all condense the information.. ABS Pipe + 0.6:1 ratio = Not much trouble with the RCMP and some fun? :p

PS : If anyone could add me on msn cause I got a lot of questions and I dont want to be annoying, please send me a pm and ill send you my address or add you. Thanks *this is optional*

Well I don't know of the exact ratio that you should use because I have never had a problem with my gun making to much sound. From what I have heard a 0.6:1 ratio will make the gun considerable less noisy, I'm sure that someone else has had to deal with the same problem so they can probably give you specifics. The ideal ratio is 0.8:1 this means that the chamber is 80% the volume of the barrel. So you would just change change the ratio to suite you.

Well I went to see some videos and it doesnt seem THAT loud.

Its weird, but a lot of websites are contractictory... Did anyone try ABS for Pneumatic Guns with bad results?

Just look at what ABS is used for (Non Pressure rated Applications) so its not made to hold any pressure at all except of that of water under gravity. Pressure rated PVC is made to hold water pressure so it is suitable for pneumatics.

Pressure rated pvc means that it has a pressure rating printed onto the pipe. Before pipe can acheive that rating it has to be tested over and over again. Non-pressure rated pipe doesn't have to be tested at all and therefore isn't known to be able to hold even tiny amounts of pressure. But, through independent testing, abs has been found to be able to hold the pressure of a combustion cannon safely. Just make sure that the abs pipe doesn't say cellular core on it or it isn't safe for anything.

Dom wrote:Combustion gun is loud, and dangerous.

Ordering online is unfortunatly not a possibility for me

Combustions are in no way dangerous if you are safe and build it correctly.