25MM Pneumatic Sniper Rifle

Step 2 The Chamber...

REMEMBER READ THIS BEFORE STARTING and read all of it!

The chamber in a pneumatic cannon is a buffer zone between the valve and the bike pump/ compressor. It allows a large amount of air to be stored and exhausted very quickly when fired.

this is my chamber, it is a 12 inch long piece of 2" PVC pipe with a 2" cap on one side and a 2" coupling on the other, attached to the 2" coupling is a 2" to 1" reducing bushing. After the chamber was glued i let it sit for an hour (so the glue could partially cure) then i drilled a 1/2" hole in the side of the 2" cap so i could thread in the brass quick disconnect. do not use any Teflon tape on this fitting, if it starts leaking put some epoxy putty or JB weld on the section where the threads meet the chamber.

Comments

[fr05ty911]

instead of gluing the chamber in could you use a quick disconnect so you wouldn't have to keep refilling it and just swap chambers???

[djzadjza]

thats a god idea but the disconnect might be two small so you would have to use some reducers.
but that would be a very good idea if you were using the gun away from an aircompressor... infact i might try that

[popcannon]

maybe u could hav a hwhole second tank with a female disconect at one end and a male discnnect at the other, so u could fill it at the commpresser and then when u wanted to use the cannon away from the commpresser u could fill from that

[deobomb]

yeah you could make it snap on and off to make a fast change air tank

[shaclonts]

Wouldn't that not work because the whole idea of the compression chamber is to quickly release the air? If you could do it that way you might as well keep it attached to the compressor and forgo making the compression chamber altogether.

[blubberdubber]

Where can I get all the materials needed for this in the UK? I can't find PVC in particular.

[bearzcrazy54]

how much was this whole gun? can i use a paintball co2 tank instead of the PVC pipe

[abyrne45]

How much did this thing cost to build.

[dan5jr]

Would there be any problems with using a tire (Schrader) valve instead of the female quick disconnect?

[DIYtheKid]

Schrader valves that use a piece of flexible rubber hose to control the direction of flow leak a little..  ball-check valve shouldnt leak as much but car tyre valves seem to not leak at all.

 

[djmelton9]

That is what alot of people use. i find it easier to use that anyways because you just pop it in the hole and glue it.

[yourworstnightmare]

how much does the whole project ccost if you don't have anything?

[andersd22]

This is sick, but what does it shoot?

[maxpower49]

what ever fits in the berral

[uzairsagitarian]

HELP! HELP! HELP! HELP! QUESTION: I have found in my local market (PAKISTAN) the pipes with following ratings (PVC 1" SCH 40 PSI 450 ASTM D-1785) and (PVC 2" SCH 40 PSI 280 ASTM D-1785) Does that mean that they have pressure ratings of 450 and 280 PSI respectively? Help would be really appreciated

[bombmaker2]

http://www.engineeringtoolbox.com/pvc-cpvc-pipes-pressures-d_796.html

[weasel999]

no 40 psi

[Axel_The_Wicked]

isn't it a better idea to use a material that's less likely to explode under such pressure? what other kind of material could the air chamber be made out of that wouldn't explode?

[neetam123]

whats the range of this air gun?

[uzairsagitarian]

brass quick disconnect is primarily used to fill the chamber with air, right! Can I use a car's tyre filling valve instead ?cuz it is cheaper to find

[Punished07]

I was thinking about putting 2 air chambers on by just using a Y and a two ball valves and was wondering what you thought. Is there a better way?

[championpyro]

Im having a little trouble with finding the right kind of quick disconnect valve. Could you put up another picture of it, and the different parts of it.

[BloodRoger]

the drill works if your short on tools but to make a better fit you could use a tread cutter set to maximize its a ability to hold pressure

[pbpenguin5]

Could you explain a little how you attached the female disconnect, i have a fear of filling the chamber and the little metal slug backfiring and imploding myself. i've almost taken my thumb off with a smaller and less destructive version of this.

[irwinner]

basically you drill a hole that is smaller than the smallest thread on the fitting (the smallest thread is found towards the bottom of the the fitting because it is tapered) then simply screw it in. the metal fitting will carve threads into the plastic pipe with ease, if you still don't feel safe a bit of 60 minute epoxy would make it stronger

[pbpenguin5]

ok thanks, nice sniper btw and i'm gonna try a .50 caliber version =]

[hideogama]

PVC is rated for water pressure and not air pressure. There is quite a difference when it comes to the viscosity of water and air. I would use PVC 80 for the air chamber at least, if not some old mini fire extinguisher or something similar.

[irwinner]

yes you are correct they are water pressure ratings but sch 40 pipe is fine to use as long as proper safety precautions are taken. as a general rule use the pipe at half its pressure rating (2" pvc is rated 200+ psi, im using it at about 100psi) second never leave it pressurized for long periods of time, third never use it in the cold of winter (below 40 degrees F) and lastly always use pressure rated fittings (as opposed to DWV)

[airhead1000]

what is the gold thing on the cap of the barrel, is it a bike valve?

[a random John]

Any reason why you selected schedule 40 PVC instead of schedule 80?

[irwinner]

schedule 40 is cheaper and more readily available, besides the rating on the two inch pipe is still way above what im filling it to (like 100psi or more above what im filling it to) the sprinkler valve fails around 150psi i believe so you wouldn't even be able to use the schedule 80 to its ratings, but if you have some it would be safer to use it over schedule 40.