Mini, regulated, cheap air supply?

Building or modifying BB, Airsoft, and Pellet type of guns. Show off your custom designs, find tips and other discussion. Target practice only!
User avatar
lozz08
Specialist 2
Specialist 2
Posts: 239
Joined: Wed Jul 01, 2009 7:33 am

Mon Sep 28, 2009 11:37 pm

I am going to make a handgun semi-auto pneumatic, I wont go into the design, but I have this problem... I need a supply of air built into each magazine that will give me 200PSI for 12 shots. Chamber volume is about 2cm cubed, so I need 24 cm volume of 200 PSI air. But I dont know how to make a regulated air supply or anything.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26179
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 543 times
Been thanked: 319 times

Donating Members

Tue Sep 29, 2009 12:08 am

lozz08 wrote:Mini, regulated, cheap air supply?
I don't think you can make a coherent sentence with those words. If it's going to be mini and regulated, it's not going to be cheap.

If you're on a tight budget something like this will have to do. Just one of these hooked up to your launcher and the magazines just for ammunition.
User avatar
grock
Specialist 2
Specialist 2
Posts: 231
Joined: Mon Dec 29, 2008 2:59 pm

Tue Sep 29, 2009 12:50 am

you could try modding a crossman c11 (airsoft gun) you can find those at walmart for about $35. they shoot .2g bbs at about 550 fps when new, and settle to about 400 later.
User avatar
lozz08
Specialist 2
Specialist 2
Posts: 239
Joined: Wed Jul 01, 2009 7:33 am

Tue Sep 29, 2009 12:53 am

Australia, otherwise I'd just buy bb guns but I have to make em.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26179
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 543 times
Been thanked: 319 times

Donating Members

Tue Sep 29, 2009 1:06 am

The bottle I suggested above hooked up to a blowgun and magazine setup will probably give you enough semi-auto shots for an average skirmish without needing to be refilled.

You could go even simpler and make a BBMG like this one.

Image

Image
User avatar
tghhs
Specialist
Specialist
Posts: 176
Joined: Wed Dec 31, 2008 11:01 pm

Tue Sep 29, 2009 2:51 am

lozz08 wrote:Australia, otherwise I'd just buy bb guns but I have to make em.
Cool man, another AUS spudder, where do you get your bb's?
User avatar
lozz08
Specialist 2
Specialist 2
Posts: 239
Joined: Wed Jul 01, 2009 7:33 am

Tue Sep 29, 2009 5:18 am

Well, theres a place called outdoor wharehouse based in brizzy that ship 0.12g and steel bb's, problem is they're both bad weights to be using for airsoft purposes, but I think I can live with 0.12g for now. Gonna try order some 0.25g from china and say its slingshot ammo (loophole).
User avatar
lozz08
Specialist 2
Specialist 2
Posts: 239
Joined: Wed Jul 01, 2009 7:33 am

Tue Sep 29, 2009 5:26 am

The epoxy gun is cool, the piston design is great, I think I might use that. One Question, how does a regulated air supply work without a compressor? I know CO2 tanks give off a steady pressure because its going from liquid to gas, but can you have just a normal air tank thats regulated?
User avatar
POLAND_SPUD
Captain
Captain
Posts: 5402
Joined: Sat Oct 13, 2007 4:43 pm
Been thanked: 1 time

Tue Sep 29, 2009 6:46 am

what about unregged propane ??
can you have just a normal air tank thats regulated
yes.. that's how HPA setups work
Children are the future

unless we stop them now
User avatar
lozz08
Specialist 2
Specialist 2
Posts: 239
Joined: Wed Jul 01, 2009 7:33 am

Tue Sep 29, 2009 8:26 am

Lets say I calculated that I have a certain amount of space in my mini tank, and I know that each shot takes a certain volume of air at a certain pressure. Lets say I calculate what pressure I need to fill my mini tank to, in order for it to be able to supply enough air for 12 shots. Is there a valve I can stick in my gun that will, when opened, only allow a certain amount of air in and then immediately close? thats really what I'm looking for here.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26179
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 543 times
Been thanked: 319 times

Donating Members

Tue Sep 29, 2009 9:04 am

What is your tank going to be made of, what facilities do you have to fill it?

If you're a bit creative with materials you can make a hammer valve, like a blowgun but instead of actuating it manually you strike it with a hammer so it only opens for a brief period. There are devices containing ready made hammer mechanisms like cap pistols or automatic staples.

Image

Image

You might also want to look at Antonio's designs like the P2 and P3, ingenious use of commonly available materials without the use of sophisticated tools.
User avatar
lozz08
Specialist 2
Specialist 2
Posts: 239
Joined: Wed Jul 01, 2009 7:33 am

Wed Sep 30, 2009 11:43 am

Ok, I think I'm gonna go with a co2 semi-auto. My main concern is economy because I dont wanna be buying heaps of little co2 cartriges (using 16g threaded cartriges) These guns I'm making will be for close quarters only, so I only need a joule of energy, and I'm gonna use 0.12g bb's. What I'm really concerned about is making the same amount of gas come out each shot, but in a small package (handgun) And keeping it semi-auto. Got any tips for me?
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26179
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 543 times
Been thanked: 319 times

Donating Members

Thu Oct 01, 2009 12:11 am

If you're willing to put the effort into making a hammer valve of which I already gave plenty of examples, then a 16 gram CO<sub>2</sub> cartridge will give you a lot more than 12 shots.

Alternatively you can hook up a tyre inflator directly to a magazine like this little thing and fire short bursts only, it will be semi-autosih with a lot less effort.
User avatar
lozz08
Specialist 2
Specialist 2
Posts: 239
Joined: Wed Jul 01, 2009 7:33 am

Thu Oct 01, 2009 2:08 am

hammer valve sounds good. Could you point me to some of your threads on it?
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26179
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 543 times
Been thanked: 319 times

Donating Members

Thu Oct 01, 2009 2:39 am

lozz08 wrote:hammer valve sounds good. Could you point me to some of your threads on it?
As mentioned before the best (in terms of ease of manufacture with basic materials and facilities) I've seen on this forum are Ant's designs.

Image

If you want to use CO<sub>2</sub> cartridges, my best advice would be to get your hands on one of these - not too expensive - and then create a mechanism which strikes the trigger. You can either make this from scratch or find some sort of toy revolver with a working hammer that can do this for you.

You can then hook it up to a barrel and a simple tee magazine as I used here.

Image

This way you will get much more than 12 shots. Typical CO <sub>2</sub> pistols (with significantly more than 1 joule of energy - therefore using more gas per shot) will give 80 or so shots from a single 12 gram cartridge, you will have a weaker hammer so use less gas. This way it would be ideal to have a fixed magazine on your launcher.
Post Reply