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New to Pneumatics :(

Posted: Sun Nov 25, 2007 11:40 am
by furball
I was thinking of making a gun. I had bought some PVC pipe and stuff and it didn't go so well....Basically I've wasted £30. (YES I AM ENGLISH, GET OVER IT!!!)

Over here, it's really hard to find all these parts unless you get a specialist UK website which is generally expensive. I can't just go to my local DIY shop and buy etc.

I wanted to make a ball valve operated gun, prefably plastic due to metal not being air tight. I know all the safety procedures and risks of using PVC. Basically, I want to know how to build a cheap (if possible) good - looking sniper (complete with a cheap scope :wink:)

This would be my first cannon (NOT SPUD CANNON, Marble/paintball) so I'll be using 3/4 and twice the size of that as a chamber.
Any help appreciated.

Re: New to Pneumatics :(

Posted: Sun Nov 25, 2007 12:07 pm
by Ragnarok
And what exactly is wrong with being English? There are many English (and people from the rest of the UK) members on this site, me included.

Metal can be perfectly air tight. Look at my own cannon HEAL. That's totally air tight at pressures probably 2 or 3 times what you're likely to be using.
However, that's quite a complex design, and also pretty expensive (but worth it!). I guess you'll want something a mite simpler.

Ball valves are not a good choice. Not only are they low powered, they seriously throw your point of aim when you twist them - making any scope next to useless.
Also, most UK PVC pipe is not rated, so I would seriously advise you use copper pipe for the construction and a QEV (Quick Exhaust Valve) for a main valve.

A good choice would be to make something based on Hotwired's beautiful Copperhead Prime, just scaled up for the right barrel size (and a larger main valve and chamber wouldn't hurt). Copperhead was designed for quite a low budget (£100, although some later changes increased that a little), and making it a little larger will affect that pricing, but you could easily change it round a bit to cut out non-essential components.
For example, you could make it like Maxus' Copper pneumatic.

All those designs are made with parts quite easily available in the UK, and are nice powerful, consistent and reliable designs.
Anyway, I'll leave you to think that over. I really really suggest you don't go for a PVC ball valve design, it's going to be unsafe, and inefficient.

Posted: Sun Nov 25, 2007 2:20 pm
by furball
£100 budget?! Low?!!

I could buy a real air rifle (1000 PSI) for that!


As I said, I have no experiance and I doubt I'd be able to make a successfull copper gun.

Posted: Sun Nov 25, 2007 2:24 pm
by jrrdw
If you can soder a water pipe, you can build a sniper out of it. Have some faith in yourself. Or just buy one from www.bcarms.com

Welcome to Spudfiles.

Posted: Sun Nov 25, 2007 2:30 pm
by jackssmirkingrevenge
I could buy a real air rifle (1000 PSI) for that!
Not for 100 quid you couldn't, not a decent one at least.

I would agree with Ragnarok's suggestion that you use a QEV, it might seem a little expensive but great flow and opening time for a 3/4" barrel, it's practically a ready made piston valve. the rest of the fittings can be PVC, that's not a problem as long as they're pressure rated.

Posted: Sun Nov 25, 2007 2:48 pm
by Zen///
Well my ball valve/burst disk gun has a scope, but it isnt that hard to aim....

I could buy a real air rifle (1000 PSI) for that!
HA!
http://www.glbarnes.com/Nebula_2.html
5000$
A REAL air rifle.
YES I AM ENGLISH, GET OVER IT!!!
(more?) Than half the people here are "english"
(if you are reffering to UK citizens)
As I said, I have no experiance and I doubt I'd be able to make a successfull copper gun.
My first gun was copper, GET OVER IT!!!

Posted: Sun Nov 25, 2007 2:55 pm
by jackssmirkingrevenge
Zen/// wrote:http://www.glbarnes.com/Nebula_2.html
5000$
A REAL air rifle.
I'd rather have something like this from Dennis Quackenbush, high on power and accuracy but at a much more reasonable cost and it doesn't look like something that fell out of some modern art exhibition ;)

Posted: Sun Nov 25, 2007 3:15 pm
by Ragnarok
Ok, in response to the PM, I did the rounds of all the good UK websites, and...

I couldn't get even a very modest design to fit the £50 budget you wanted, no matter how hard I tried, but if you're willing to spend a little more, I think a nice little cannon could be made for ~£70-£75 that would only need some skills with a couple of wrenches and a hacksaw - no soldering.

And for that you'd have something about 4-5x more powerful than the average UK air rifle when using paintballs, 5-6x with marbles, and a little higher than that with heavier ammo.

Accuracy wouldn't be too bad, but still, don't expect high precision shooting from anything with a smoothbore.

Posted: Sun Nov 25, 2007 3:19 pm
by jrrdw
Off Topic:
Jack is that a CO2 air rifle? A 430 grain at 3000psi, 732fps is kinda hard to see where it gets it's power source from. A shrader valve in the front??? 660 dollars usa!

Posted: Sun Nov 25, 2007 3:25 pm
by jackssmirkingrevenge
jrrdw wrote:Off Topic:
Jack is that a CO2 air rifle? A 430 grain at 3000psi, 732fps is kinda hard to see where it gets it's power source from.

The rifle is made for HPA but there are ones for dual power, but they get more ft/lbs from air than CO2
A shrader valve in the front???
Not a schrader but a quick-connect male fitting, you can get adapters cheaply.

Posted: Sun Nov 25, 2007 4:10 pm
by Infernal Maveric
I too shoot spuds in the UK (but I'm not English) and copper pipe is by far the best material to use as the PVC we can get in stores are not pressure rated. Soldering is a piece of piss and is impossible to get wrong. It can look/get messy, but not go wrong.

I would say that £100 is a reasonable price to be looking at for a decent marble/paintball rifle, as the price of copper isn't cheap and a decent QEV is around 20 bob.

Posted: Sun Nov 25, 2007 4:19 pm
by furball
Sorry, last forum I went to I basically got patronised because I was from UK.
The 1000 PSI air rifle my friend said he got from a store in london. As far as i remember,it apparantly was £100(?)

I just want to make a basic air rifle that works, ya know? Something thats powerfull but simple :\ Just for starters, Then I'll get good with my valves and electronics and maybe construct something more advanced.

Posted: Sun Nov 25, 2007 4:22 pm
by Zen///
basic air rifle that works, ya know?
Ball valve+smooth bore= NOT A RIFLE

Posted: Sun Nov 25, 2007 5:06 pm
by Ragnarok
furball wrote:I just want to make a basic air rifle that works, ya know? Something thats powerfull but simple.
Then I seriously suggest you try something with a QEV, because ball valves totally suck. No consistency, no accuracy, no power.

In short, a ball valve meets very few of your criteria.

Take this as an example.
The launcher design I whipped up for £72 total: 65 Joules of energy with a paintball, 84 J (Marble)
If I were to swap the QEV for a ball valve: 6.4 Joules (paintball), 11.5 J (marble).

A mere fraction of the energy, and you're certainly not getting that for a proportional cost. The design I cooked up (for which I am perfectly prepared to hand over the shopping lists and the plans for nothing - I can't make it any easier for you) is a very good cost to power ratio. You don't get a ratio like that for an air rifle or a ball valve launcher.

There is no coincidence that people never go back to ball valve launchers after they've used a QEV or piston valve. My best design is a full 30 times more powerful than any conventional air rifle you can get in the UK, and shoots pretty straight too (although it can't match an air rifle for that.)
Cost about £300, but damn, was it worth it.
It's more than an low end air rifle, but low end air rifles won't blow holes an inch across through 2mm plate steel.

You don't have to spend anything like £300, ever - you could have more than enough fun with less than half that. However, you need to spend enough to get a launcher that was worth it.
It's like anything. You can spend a small amount and get a piece of crap that's just a waste of your money, or spend twice as much and get something that's worth every penny.

I'm not telling you this because I'm a salesman trying to squeeze you for every penny. I'm telling you that because I've been there, and I know a lot more about what will be worth your while than you might believe. Spend a little more and get something that's really worth it that you can be proud of.

Posted: Sun Nov 25, 2007 6:21 pm
by furball
The most I'd spend is £70 tbh :\

Thank you for your help. And shopping list? Is it from the same store? If this gun goes well, proably, I'd stick with it and make ajustments I guess.

Lets see the materials and stuff please :D

I'm excited.