Page 1 of 1

first gun-onto the building

Posted: Thu Dec 03, 2009 1:52 am
by bradisfun
ok well tomorrow( or some time on the weekend ) i will be going to get by parts, so i will tell u a little about the gun i want to build, this will be my first gun. so i want it to be a snipper with chamber mounted on my back with compressor(1 of those 1 that Claim to beable to go up to 300psi)i need help with this next part, do i go with just a compressor hose or should i go with something with a wider diameter? this gun will be made out of pvc and might have a red dot sight in the future
so heres the parts list
-sprinker valve
-pvc parts (will get the pressure raited stuff but not DWV)
-hose(not share what type but either compressor hose or a braided hose with a larger diameter, i need help with this)
-compressor(crappy little 1)
-fill valve(not shore what type yet)
-quick attach compressor hose fittings

so just tell me what u think and if u think i've forgotten any thing
thanks

Posted: Thu Dec 03, 2009 2:29 am
by grock
well, i can tell you for sure, that those crappy little ones are just that. crappy. it might give 300 psi, but the volume/per time is most likely so small that you would be better off with a bike pump, or running inside, filling it from a real compressor, the going back outside.

for you fill valve, you have two real options. there are schrader (tire) valves and quick connects. the advantage of a quick connect is you can keep it connected to your main air supply without having to connect and disconnect it with each fill. it also means you have to be tethered to your air supply, because quick connects on the part-being-filled-with-air, aren't airtight, in fact there hollow, and will cause your gun to not hold pressure when disconnected. you could always go with a quick connect, and make an adaptor out of a female quick connect, and a schrader valve for when you cannot be tethered to your compressor.

sprinkler valve: consider modding, much more performance and convenience is added, no wires. if you want to stay with electrical activation, its alot more convenient if you rig up some kind of electrical switch so that you can fire it without trying to hold your gun at the target and use both hands to connect wires at the same time

unless it is for a specific purpose, or extremely heavy, don't backpack mount your chamber. the hose, unless it is of a large diameter, will constrict flow and decrease performance. id recommend taking two 90* fittings and making an under/over launcher, better performance, and more mobility

Posted: Thu Dec 03, 2009 2:51 am
by bradisfun
thanks yes i did plan on moding the sprinkler valve(sorry forgot to say this) and i want to beable to take the gun places with out having to bring my air compressor evry where i go thats the reason for having the crappy compressor and the back pack is just something that i really want to do so that i can have a biger chamber without having to have it in my hands ( with the backpack mounted chamber i can put all my stuff in it like the compressor and my ammo and what ever eles i what), i think that i will go with a 1/2 inch hose of some sort (going to bunings tonight but i wont be getting anything)
i also forgot to mention that the barel will be 15mm in diameter and about 130cm long(what do u think of this)

Posted: Thu Dec 03, 2009 3:26 am
by grock
well, if your going to use a 3/4-1" sprinkler valve, all that flow might be (dont take my word for it) wasted on such a small diameter barrel. you want as wide hose as possible, because it seems like that will be your limiting factor onhow much power you can get. think of it this way. if you were to pump water, would a 1/2" hose work better or a 2" hose? you could try playing with ggdt, just plug in what its asking for and your good to go.

as for a compressor, you could try this one, it works great for me, but i rigged a batter pack so im not tied to a car either. its also really quiet and fills 60" of 2" diameter pipe to 60 psi in about 30 seconds, to 100 psi in about a minute

Posted: Thu Dec 03, 2009 3:36 am
by bradisfun
yeah thanks that was the sort of thing that i was thinking of and that is another reson of the backpack so when i go to bunings to night i will look for a 1" presher rated(or what ever some ppl say that it's not the presher rating but the safe working presher) hose



Well i went to bunings and found every thing i need and will be making the gun prity soon and was just wondering if i would help if i used a 20mm fired by a blow gun to fire the sprinkler valve