SpudFiles

Hello ..
Finished this today its about 4 months in the making.. Combination of laziness and a few issues that came up.

I started off wanting to build this as cheap as possible, and even though it did ultimately cost me more than I wanted iv'e got a bunch of spare parts plus it actually works better than expected so I'm happy. Nearly everything for this was bought from fleabay and should be easily available to anyone, the only parts I got locally were the barrel itself (which was quite cheap (IMO) from a local metal supplier) and the co2 cylinders. The only thing that I couldn't do by myself was getting the 1/2" thread put onto the barrel which I asked family member to do for me, he tried to explain that the 1/2' thread I wanted was near impossible to get as a simple die so he turned it on the lathe, I have no idea if this is right I could swear I have seen a 1/2" die myself, but who knows, anyway it just worked out easiest for me. Its something most metal shop can do and I assume it would be reasonably cheap.

Here's my parts/price list:
$30 - 3x Soda Stream Cylinders (second hand, these were also fleabay but were local)
$35 - 2x Soda Stream Adapters (only one needed other is for another gun)
$26 - UP Aquarium Simple Regulator for Plant Aquarium A-148
$12 - 1.5m Stainless steel 8mm ID tubing from local supplier)
$10 - (1x 300PSI)(1x 600PSI) Paintball Micro Gauge CO2 (only needed one but I got two & using 300PSI right now)
$9 - Air Compressor Gun Blower/Cleaner
$9 - Air Compressor Replacement Switch (240v switch goes on top compressor)
$6 - 4x20 Air Rifle Scope (el cheapo ebay but still works OK)
$6 - 'XQ170600' 1/2" Quick Exhaust Valve
$8 - Nipple 1-1/4" x 1/2" Female Stainless Steel 304 Threaded Reducer Pipe Fitting
$6 - 1-1/4" Male x 1-1/4" Male 304 Stainless Steel threaded Pipe Fitting
$5 - 1 1/4" 1.25" Stainless steel Pipe fitting Cap
$5 - 3x 0.236" x 0.137" Brass L Shape Male Elbow Quick Coupler (ONLY 2 NEEDED BUT IF YOU USE THESE BUY A SPARE!!)
$5 - 3m Co2 Proof Tubing Polyurethane Air Pipe (is NOT 'Co2 Proof' picture proves I found that out the hard way!!)
$4 - Brass Male Adapter 1/4" x 1/8"
$3 - Brass Male Adapter 1/2" to 1/4"

TOTAL : ~$180
(with extra tanks, extra adapters, extra hose, extra barrel (only used half/75cm of the tube) but also put me way over budget when I wanted to get it done for under or at least around $120.

A few other things I needed were thread tape (LPG gas tape), sealant (used high temp RTV engine sealant mainly because I already had it), a few tools (mainly tap/die set).


Basically I have it set up like this:
Co2 Bottle->Adapter->UP Regulator...
The hose connects the co2 line from the regulator to the 'back' side of the duster 'gun' the PSI gauge is also on this same inlet side. The QEV is attached in line with the 'gun' with my tank on the bottom (tank made from the 1-1/4" Stainless threaded Pipe Fittings I bought) and then of course my barrel which right now is muzzle load not that its really a bad thing for me.

The last part is the little mod I did with the air compressor switch to make the finger trigger release for the QEV. ... Basically this is the little air pressure switch that turns electric compressor motors off and on. Its just a beautifully simple little switch that works perfectly as a release/trigger to dump the air out of the QEV.

So realistically I have two triggers, the original one you see on the duster gun which primes the QEV tank and gets it up to pressure, I then release that one and its ready to fire with the small push switch attached the short length of co2 tubing positioned perfectly for my trigger finger, very little pressure or movement is needed to actually dump all the air from the back of the QEV and fire off the pressure and very little gas wasted.

There is a slight issue though, since I thought the regulator would (at least some what) regulate the pressure itself (which it simply doesn't) I really need to figure out how to get it a steady ~150-200PSI from my co2 bottles.. For the moment I have to make completely sure to turn the 'regulator' 100% off each time after priming it otherwise the pressure just keeps rising and ive now learned the hard way what happens when I dont...
I did use safety glasses for the testing phase, although in hindsight probably should have also used some heavy gloves and hearing protection..lolz, Last night I scared the life out of me and the mrs (oh also the cats) when the co2 'proof' hose burst at ~500psi.
The cheap hose I bought from ebay obviously needs to be replaced with something like proper paintball macroline, don't really want it to burst again that once was enough for my ears.

It takes 8mm rounds which is basically the same as size 0 sinkers so I was thinking of just getting a sinker cast and making my own rounds on the cheap. It also needs the little scope to be mounted somewhere. The one thing for me was I wanted the heaviest part (tank-adapter-regulator) to be carried remotely on a belt clip or similar to make it as light as possible that's why I made it as a 2 piece.

My QEV seems to work fine at 200psi so far (which I think is already over its 'rated' capacity but im not sure how long it would last with any more pressure) I have the 600PSI gauge if I ever do make up something that can handle more.. I also was pondering about a loading mech, perhaps I could have a feed load T piece setup with some type of O ring as a retainer, Im really not sure yet (suggestions would be great if anyone has thoughts) might just keep that side of it as is though haven't really decided.

Well its not really 100% done but close enough I just wanted to show it off and list exactly what made it work. If anyone has any suggestions about regulating it properly id REALLY love to hear that's my one main problem at the moment so any help would be highly appreciated.

Anyway what do you spud heads think??
Peace
Wally

There is a slight issue though, since I thought the regulator would (at least some what) regulate the pressure itself (which it simply doesn't) I really need to figure out how to get it a steady ~150-200PSI from my co2 bottles..

You might have a flow regulator in stead of a pressure regulator.

It would be safer to disconnect the bottle each time after filling.
You're actually lucky it was the hose that blew...seems to me the blowgun is the next "weak" link.

Metal schrapnel is less forgiving...

Nice gun but, if it is qev you should have made a breach loader if you look around you will find many breach ideas.

Brian I think your 100% right about it being a flow regulator (it is for an aquarium) can you please give me an example of an actual pressure regulator that I could use or am I SOL here? I do also think you are 100% right when you say it would be safer to disconnect it (would stop all accidents etc)
However..
I actually thought about it before doing any testing at all, both then and still now Im thinking the weakest link in the chain is probably the small fittings on the right having the rubber hose simply popping out from their barbed / screw im fairly sure they would pop off before the gun itself exploded dont you think? (well I would really hope anyway but I do know there are always extenuating circumstances where anything can and will happen, for all I know the handle could explode at 200psi.. ), of course though I already found out that the hose cant take that kind of pressure for long..
After you pointed that out though it made me think more about it and I am truly glad the hose blew and nothing else of course it could have been really bad.. Do you really honestly think the handle would explode before say even my small M5 threads gave up and stripped out or the hose simply popped out of a fitting? I thought these things would be more likely to happen.. ?..

I might just attach a ~200psi pressure relief valve if I can find one of course that would stop this happening as well as easily tell me when im up to pressure..


Well anyway I know I have to be VERY vigilant yes it would be safer to completely disconnect it but id much. much prefer to just be able to regulate the pressure down to the gun properly.


Thanks Dart Guy, yeah I have seen a few breach load rifles in the forums (I have been lurking for probably six months) I just wanted to get this done (I mean working.... not completed) and then maybe see what needs upgrading / fixing and just see what I want
(I do still have a spare identical barrel which I could use to do the loader).
I actually just mentioned to the mrs about a breach loader and I think she made the decision for us to do it already so hopefully ill have a more completed (hopefully safer) airgun in a month or two..

I actually just mentioned to the mrs about a breach loader and I think she made the decision for us to do it already

Mrs Wallis ..I mean Warez ..makes spudgun decisions?

haven't heard that one...apart from the "that thing stays outside!!!"
sort of decisions...
You're one lucky man!!

I use a regulator from an oxigen welding tank.
I just swapped the fittings to match the bottle I use.

Another option would be to regulate the pressure yourself...just monitor the pressuregauge and shut the flow off when your desired pressure is reached.
A safety pop-off would be best to back you up in case you screw up.
Better to have one installed intentionally than gamble on a particular part to fail before another does.

As CO2 is rather tricky ( liquid could make it's way into the launcher and expand there) and expensive...I'd advise you to consider making your own stirrup pump.

Small fittings have small surfaces, wich results in small force appled by the pressure.
M5 fittings will often take tremendous pressures.

The blowgun is cast aluminium, wich is less likely to withstand very high pressure.
It's pretty safe at 200 psi, but you shouldn't become careless.

The surface area inside exposed to the pressure is also bigger, while the aluminium itself could simply crack at the threads if you were to drop the launcher or bump it in the wrong spot.

A small hiss is enough to set off a QEV...so once pressurised:only point at something you're comfortable with destroying...
To keep safe you should handle it in the same way unpressurised.That way you can never be mistaken.

i am picturing an m4 design if you can make a loading device, then some thing like this
this may be a good idea( have a floating guard made from thin pvc and a little silencer built onto the barrel would help you not annoy neibors also you don't need a scope it is just in my images)hope it gives you some inspiration.

Monitoring the pressure level and shutting it off manually myself is exactly what I have been doing (after the big bang), its the only way I can reliably use it without it over pressuring on me..

I checked everything 110% for leaks (extremely well with soapy water sprayer.... actually checking leaks is the reason I accidental over pressured it in the beginning because of course the co2 kept leaking out and I kept having to chase the leaks and when I finally got them sorted out I forgot to completely shut off the valve and BANG!.haha)...
Last night I pressured it up to 100psi then left it all night, this morning I found the QEV still primed ready to fire with I believe the full 100psi (or close enough) still there.

Like I said I did accidentally over pressure the handle up to around 500psi when the hose burst so I think the handle is going to be more than safe at 250 or under although I certainly will still consider some reinforcement/shielding in some places.

Yeah I did the big safety talk last night when the mrs wanted to try it and started waving it around like a lunatic... haha She thinkgs its really cool and is more than happy with me playing/testing it inside, she said as long as I dont "shoot one of the cats"..haha, The thing is I actually have a Police man as a neighbour (hes a good bloke but yeah who knows what hed say if he saw me with this) so thus far Ive only done one shot outside (testing its longer range to see if my barrel is even shooting straight) vs. 5 or more shots inside (mainly testing power at different pressures), unfortunately living in suburbia I didn't initially make this thinking I was going to be able to do a whole lot of shooting directly around my home but my mum has a farm with tons of wild rabbits (potential free cat food) though honestly this just seemed like a fun idea, and I just like to make these sorts of things not necessarily to use them so much, I made a few PVC orange and golf ball cannons when I was a teenager about a decade ago .. I also things its good how it is right now because as it is I can basically unscrew everything and carry it in my car wtih no funny business from nosey coppers about the gun looking thing in the back seat.. Its easy enough to get almost completely apart if needed and then back together.

I tested it a few times today at 200PSI and I didnt realize the difference it is really like day/night compared to at 100 I think im going to definitely get either a 225 or 250psi relief valve (both are available) since I have read here somewhere these particular qev's can take up to or around 250 it would be too good to be able to try it out with even a little more power.... Im surprised the QEV is actually really thin walled compared to my actual trigger/handle I assume that this QEV is also likely cast aluminium? (it feels very light) If it is surely that would crack/split or burst open well before the handle (id say the QEV has only 2-3mm thick walls where the handle has at thinnest probably 3-4 and up to at least 5mm in many parts (id guess for the most part its probably only half as thick).. Should I be more worried about the QEV exploding is there any stories of this happening here? (I mean Ive already inadvertently tested the handle to 500 so I feel some what OK about that at 200psi for now but you have me worried about a few things I didnt consider before)

Hey Brian actually Co2 is not that tricky nor expensive and the beauty is I can get a full ~850psi from it (if I have the right setup of course) at 850 im fairly confident it would do some major damage.. Also im sure you know there is a really good reason its called 'dry ice'... there is literally no such thing as 'liquid Co2' (its just a misconception many have) honestly if I really want to cheap out I can buy blocks of dry ice locally (something like $5 for 1Kg I think) which will be enough to DIY fill all of my bottles and then some, pretty cheap me think..

How many PSI can a shock pump get up to? One of my initial 'goals' was I wanted to make a gun that could shoot at least few dozen (hoping for around 50) rounds at full pressure and for it to be semi-auto, maybe I can still get close to this goal I just need to test how many shots I can fire with this cylinder.


Cheers again for the suggesting guys, dart I was thinking today about maybe a bottom spring fed system with it set up so when I fire the spring is compressed and thus only allows one shot through at a time.? It would be great to have 10 or 20 balls in there ready to fire one after the other but then again with a bolt/breach type setup I could actually also cast and use proper shaped pointy tipped ammo.. Ahh too many options..haha

Well I might upload a video of a test fire soon ill see if I can get a good video tomorrow sometime..

Heres a few photos of my test today, the first was at 100PSI and the sinker half flattened but only left a small dent maybe 3mm depest probably closer to 2mm, it just bounced off and across the room, the second test at 180PSI you can see the sinker is more than half embedded in the bed slat, this was from close range (around a meter).
This wood is fairly solid its an old timber bed slat.
I tried on some 8mm plywood at 180PSI from about 4 meters and it went straight through (last two pics).

This guy has an extremely similar setup to me and he says there hes using his up to around 430PSI so I hope mine should be OK at 200-250, of course thats if the QEV can also take it..

http://www.spudfiles.com/forums/sodastr ... 22079.html

Good job and well documented

The QEV can take a lot more than its rated pressure, here's an example of the sort of abuse they've been put through on this forum: http://www.spudfiles.com/forums/600-psi ... 17298.html

The weak link is the blowgun, in my experience these will start to leak beyond 500 psi or so.

You might want to consider switching to a ball valve as a pilot, it's not an immediately convenient pistol grip shape but with some imagination:

but my mum has a farm with tons of wild rabbits (potential free cat food) though honestly this just seemed like a fun idea,

As long as the cats catch their own rabbits...

Talk about hunting is prohibited on our forum....

there is literally no such thing as 'liquid Co2'

Care to elaborate?

how many PSI can a shock pump get up to?

I got mine up to 80 bar before the checkvalve blew and the handle was launched into my face...broke my upper jaw.The section containing my front teeth was seperated from ..well...the rest- from my nose down.
At least...as far as I could tell.
Stripped the gums off my teeth down to the bone..
Healed up nicely though..took a year or two to fully heal.

My dentist will make an x-ray photo next visit, at my request ,to confirm my assumptions.Or not.

Since that incident I started taking safety more serious..

You might want to consider switching to a ball valve as a pilot, it's not an immediately convenient pistol grip shape but with some imagination:

Wow..that looks like it was created by a genius..

But with multi-shot in mind I would go for..QEV/hammervalve!!
Works for me!

( edited spelling and on a sidenote: Yippie..38 years and one minute!)

Are you saying you pumped a similar handle as my one to over 1000PSI or was it something different..?

Elaboration: Ok Im obviously completely wrong with what I said about Co2..

I honestly didn't know hunting was a no-no sorry about that...




Thanks again for the help (and for not straight out calling me a d*** after the last post)

Hey jackssmirkingrevenge, from your experience can I please ask where do you find they usually start to leak from? Is it the O rings in the trigger itself or something else?

Thanks again guys. 8)

warez.wally wrote:Hey jackssmirkingrevenge, from your experience can I please ask where do you find they usually start to leak from? Is it the O rings in the trigger itself or something else?

Yep - also remember that you've installed it the "wrong way round" - the valve is under pressure from the different area than it was designed for.

Wow..that looks like it was created by a genius..

... and a modest one at that

The derringer is a workof art, even for a modest genius. I really like that it is a coax.