SpudFiles

Hi everyone. Been following this website and what people have built for a little while but the urge to build one has gotten to strong so ive started an account and thought i would share my idea with you all for my own pneumatic and was wanting to gather a bit of information and help from others. im not going to draw a picture but if you guys need help in trying to understand my design ill get ms paint for you.

So basically the design is as follows

1.5cm piping > 3cm diameter piping> co2 tank that is used as part of the butt of the gun, possibly in aluminium rail.

I was thinking of going for piston valve design (i think it is called( all of which is on the 3 cm diameter piping)) that has a checker valve made with an aluminium cylinder and a spring, for a shorter pressurising time. The gas is let in using a solenoid connected to the back of 3cm cylinder. No here i was wonderign if i could use a 555 timer or something to that accord to fill the tank up automatically by pressing a button and allowing the electronics to keep the solenoid open for a certain time. im guessing a could fiddle with it to get the best amount of time to keep it open.

Now one problem that i have is that i gotta release the air from behind the piston to obviously get the gun to work but i would like to do that in a trigger mechanism fashion? I was also wondering how i could make this bolt action to reduce loading times without loss in pressure. I will be placing the loading area close to the chamber to reduce what i think is called the 'dead space' if im correct. i did have a design for the bolt action loading but it was only for a pvc design and i dont believe it will work with metal pipe which is harder to work with. This leads me to my next question as to where, if any australians could help me, should i buy my materials from if i want to produce a air gun that can hit 500+ psi. i do have an industrial park from my house that is about a 15 min ride. This has a large facility known as blackwoods and an aluminium store and a quite a few other stores including two plumbing stores, i think. Does anyone know of any stores that they have had good experience with? btw i live in QLD in Ipswich/Brisbane region.

Now as im sure this is getting quite long for most of you so i will stop with once last question for now and talk about other things later. Where could i get a compressed air tank from this could be attach to the air gun? so far i have thought of possibly going CO2 and using an fire extinguisher which are pressure rated to 3000psi. I am thinking of this option but i would like to cut down on my work and just buy a tank that i connnect using some 'off the shelf' connectors and what not.

Thanks for any help in advance and if you know of a page that i should just read that already contains some of this information i'd be ahppy to read.

OK so i thought that i would actually draw some pictures. so here they are.

EDIT: btw the ammo will be wax bullets. im using wax as it is easy to cast and apparently acts like lead at high enough velocities. Would 500 psi be enough for that velocity?

you can get galvanized iron pipe and fittings from bunning that can handle 500psi it just standard water pipe they say 150psi but it much more. people here i have seen used up to 40 bar(580psi)


to release the air behind the piston you could use any valve, a blowgun will give you a trigger but wont handle 500psi, use a 3 way and you can get semi-auto (wait for poland_spud for more info) if you use this option you don't need a solenoid valve.

and to get 500psi air compressor you can use a frigde compressor

500psi and a piston valve it make that wax slug go fast and hurt like hell
but its week ammo use matal ball bearings or darts

if you psiton is not air tight it wont need a check valve make sure that you piston can take the force or 500psi youll need a metal one

a blowgun will give you a trigger but wont handle 500psi

Curious... You wouldn't know of where to buy a decent blowgun, I'm looking for to finish my piston valve.

what kind of pressure do you need it for?

normal ones from bunnings are good for 200ish psi more than that you should get a pressure washer handle[/url]

have seen used up to 40 bar(580psi)

OK thanks for the galvanised iron idea -_- but my only query with that is whether those pressures where reached using teflon and just threading or was those pressures reached with welding?

with threads and probly used ptfe tape to seal it

-_- wrote:what kind of pressure do you need it for?

normal ones from bunnings are good for 200ish psi more than that you should get a pressure washer handle[/url]

I don't think I'll use it for more than 200PSI. I've only spent $25NZD on the chamber, piston assembly and barrel. I'd be lucky to get a air blow gun for $25.

Edit: Can anyone link me to some cheaper blow guns.

To the guys that have already posted or anyone else.
How to i get my ammunition to stay put in the barell if i was to move to different angles?

Secondly do you no of any pneumatics on this site that are semi automatic but do not use bal bearing?
I would like to use bullet shaped projectiles.

@ Russian_Kangaroo
i don't know any of the top of my head. there are a few cartridge fed gun that use shotgun shaped ammo but they hold a bb or something inside

@ Matt_NZ
the one i liked can handle 2000psi thats why is cost lots, but bunnings should stock blow guns for under $25

hi,
Do you by any chance come from Russia ??

I suggest using galvanized fittings and pipes, I am sure you have them there since it's the most common plumbing material used here too





uhmm you can check my semiauto gun here ->
http://www.spudfiles.com/forums/semiaut ... 20259.html

it uses a QEV valve (piston valve) and a 3 way valve for piloting the QEV... usign these two you an build a semi automatic gun...
have a look at the animation there - it's harder to understand than it really is

How to i get my ammunition to stay put in the barell if i was to move to different angles?

Either tighter fitting ammunition or a spring ball detent.

Welcome to Spudfiles.

Please get a regulator for the paintballtank.
A CO2 bottle puts out 900 psi or 60 bar.

An inline regulator would take it down to a more reasonable pressure and will save a LOT of gas.

Without it you will most likely be charging the gun with liquid CO2 wich is much more dense and empties the tank much too fast without ay real gain.

40 bar will give you more than enough power.
60 is just too dangerous.

POLAND_SPUD wrote:Do you by any chance come from Russia ??

Russian_Kangaroo wrote:Does anyone know of any stores that they have had good experience with? btw i live in QLD in Ipswich/Brisbane region.

Unlikely

Secondly do you no of any pneumatics on this site that are semi automatic but do not use bal bearing?
I would like to use bullet shaped projectiles.

How isfull automatic (using 0.22" airgun pellets)

Very simple tee magazine that will not allow the pellets to fall out:



The downside is that at high pressure using a fast valve, the head of each preceding pellet was lodged into the skirt of the pellet in front of it, leading to jams, but at 100 psi or so it was fine.

hahaha yeh poland spud as pointed out i dont live in Russia but i am russian by heritage and so hence the name. That semi automatic gun looks pretty darn cool and so for that fact i think i will be borrowing some of the design aspects to implement into my own now.

To Brian: Yeh sorry, i think i did forget to mention that i would be using a regulator and try and build the gauges now into, hopefully, the wooden stock of the pneumatic. THe first reasoning behind no regulator in the first post and idea was that i kinda dont like the look of gauges on a pneumatic, it kinda just looks like something from bioshock, if you have played the game. Do regulators have the abitility to stop flow completely and can you get them with a large range of working output pressures so i could test the gun at different intervals. 100, 200, 300... etc.

JSR: That is actually a pretty nifty design that i have seen while roaming the forums but i dont think i would be able to scale to the gun i want to make. I was hoping to build a rifle - esque pneumatic that fired 50 cal round. Do you rounds fire quite strong at 100 psi seeing as there would, im guessing, be a level of leaniance in the barrel to allow for the pellets to be able to fall into the the barrel in the correct position or do the angled tails really remove most of this needed room. Im sure that design could be made in a semi automatic fashion but the the round that i wish to use neesd to be able to recieve the best fit possible.Secondly one question i need to know for that gun is how you attached the hopper? Does the pressure have a huge effect seeing as the compressed air is trying to escape and so will take any path or does the compressed air pass the closed area of the barrel that makes of the area where ammuntion comes from, having negigible effects on the ammuntion feeding area? (Hopefully that makes sense.)