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6th and last potato cannon of demon
Posted: Sat Oct 18, 2008 5:56 pm
by Demon
After 3 ball valves, 2 sprinkler who failed because they where badly modded and 2 unsucessfull coaxial...
This is my last spudgun!
Very simple:
2 inchx1foot chamber
1.25inchx2foot cannon
non-modded sprinkler valve
And thats all!
(i only need to buy the 1 inch sprinkler valve(the one in the picture is scrapped))
AND I DONT WANNA EAR ANY "MOD IT!OR PAINT IT!" OK???
Posted: Sat Oct 18, 2008 6:37 pm
by jrrdw
Your C:B ratio looks to be about 1:1. It's going to be kinda weak. I wont tell you if you don't want to
ear it. lol!

Posted: Sat Oct 18, 2008 7:20 pm
by starman
So you're quiting spudding Demon?? and you want no critique of your gun? Why did you post it?
Posted: Sat Oct 18, 2008 7:24 pm
by iisthemuffin
Haha good point starman.
And i just wanted to know how is it possible to badly mod a sprinkler valve? TWICE? I can unserstand messing up one your first time, but then buying a second one and messing it up to.
Its really not too hard if your careful.
Im not trying to ridicule you either. Please do not mistake me.
But if you do not mind me asking, what did you do wrong when modding the valve?
Posted: Sat Oct 18, 2008 8:12 pm
by TurboSuper
So how does it fire? It seems like the electric solenoid has been removed too...
Edit: Oh, never mind...it's a scrap one.
Posted: Sat Oct 18, 2008 9:03 pm
by mark.f
It needs to be modded and painted.
Good job.
Posted: Sat Oct 18, 2008 9:25 pm
by sjog
weak, that is the best you can do!!
Posted: Sat Oct 18, 2008 10:23 pm
by Fnord
Eh, you need to make a basic combustion. You won't have any problems with valves, which seem to be giving you most of your trouble
But seriously... the reason the basic spray n pray design is so widely known is because it's so simple to build and spend an afternoon with. Pneumatics can give you a lot of trouble if you're new. Oh, and good job with the clean construction and stuff.
Oh, and sjog, way to be a dick.
Posted: Sat Oct 18, 2008 10:57 pm
by TurboSuper
I dunno, I'm pretty bad at this stuff and I was able to get a sprinkler valved pneumatic up and working. Granted it has a slow leak, but it still works.
Either way, at least you've got something. The general public can't tell the difference between a modded and unmodded valve anyways so you can still impress people with it. The whole modding thing is really just icing on the cake.
Posted: Sun Oct 19, 2008 12:31 am
by jook13
Hate to say it, but I agree with sjog. sounds like you are giving up.
Truthfully, that is a nicely crafted cannon as far as I can tell from the pic. I think you should try again with the sprinkler-mod thing, just to say that you can and did achieve it. I think that if people enjoy this hobby, they enjoy taking things forward and accomplishing more. with enough trial and error (and money spent on broken valves) you will get it. then you can move on to a piston valve. then move onto a hybrid. then an electro thermal gun. then something new that blows our minds out of our skulls...
Posted: Sun Oct 19, 2008 1:23 am
by Velocity
jrrdw wrote:Your C:B ratio looks to be about 1:1. It's going to be kinda weak. I wont tell you if you don't want to
ear it. lol!

I doubt it. I remember someone telling me the ideal ratio for a pneumatic was well below that of an ideal combustion ratio, at least in terms of efficiency. however, pneumatics are a lot less susceptible to ratio problems, and thus people can bulk up their chambers without any problems. To be honest, I think 2:1 ratios are pushing it a bit (I am quite guilty of sometimes going above 2:1); 1:1 should be fine.
Posted: Sun Oct 19, 2008 3:09 am
by POLAND_SPUD
with pneumatic guns you are free to choose whatever ratio you want... it is completelly up to you, the power you want to get from it and the kind of compressor/pump you have...
you shouldn't say that 1:1 or 2:1 ratios are ideal for pneumatics... 1:1 can be an overkill if you use high pressures...
Posted: Sun Oct 19, 2008 6:22 am
by Demon
So you're quiting spudding Demon?? and you want no critique of your gun? Why did you post it?
Nope, i am not.
I will stop to build potato cannon and just shoot.
Your C:B ratio looks to be about 1:1. It's going to be kinda weak.
????What???
1:1 is the best ratio you can have!
and 2 inch x 1 foot is the chamber limit size for my bike pump...
And i just wanted to know how is it possible to badly mod a sprinkler valve? TWICE? I can unserstand messing up one your first time, but then buying a second one and messing it up to.
The first was an regular one but the 2nd was a sprinkler valve with flow control and the flow control rod casing splitted in two when i putted the 1/4 inch tit(yes, its a tit)in to it...
Eh, you need to make a basic combustion. You won't have any problems with valves, which seem to be giving you most of your trouble
I cant and prefer pneumatic cannon, funnier and more powerful
with pneumatic guns you are free to choose whatever ratio you want... it is completelly up to you, the power you want to get from it and the kind of compressor/pump you have...
I totally agree
And no its not weak MR.Sjog it can break in two a 1inch thick wood plate...
Posted: Sun Oct 19, 2008 10:42 am
by TurboSuper
The way it works with pneumatics is that the bigger the chamber, the more power you have. However, the advantages of a large chamber suffers from diminishing returns, so after a certain point you'll just be wasting space.
Posted: Sun Oct 19, 2008 11:07 am
by Ragnarok
Demon wrote:Your C:B ratio looks to be about 1:1. It's going to be kinda weak.
1:1 is the best ratio you can have!
I wouldn't rush to say best, but for a fixed barrel size, 1:1 is a good compromise between power and efficiency.
In my opinion, anything between 0.5:1 and 2:1 for a pneumatic is a good choice. Obviously, which end of that scale you choose is your own decision.