Hello everybody
Well I have been planing on building a decent spudgun for about a month ago when I was bored with airsoft guns, but didn´t have time to really think about it, as I had to study for some test.
Finally when I got a week to think about a design. Initially I wanted to build it in full aluminum, as I´m not familiar with combustions and they looks dangerous .
But I just couldn´t find any large-bore aluminum tubes and accessories ,
so I had to use PVC , but I really consider that´s not safe enough. Any way, I finished it and fired it 5 time till now , haven´t get enough courage to fire more times .
specifications:
basic gun design: co-axial.
barrel: 1 metre long 3 cm dia pvc
chamber:about 40 cm long 9 cm dia pvc, prox 1 L volume with chamber fan.
Ignition: 1.5 V continue spark ignition.
fuel: butane(I couldn´t find propane, only butane and MAPP)
I use syrige fuel injection.
Posted: Sat Mar 12, 2011 1:33 pm
by Gaderelguitarist
Those are the most strange pvc fittings I've ever seen. Be sure to check that they are indeed rated for pressure.
Posted: Sat Mar 12, 2011 1:39 pm
by jackssmirkingrevenge
Gaderelguitarist wrote:Those are the most strange pvc fittings I've ever seen.
Those of us in Europe think the same of your white PVC
Nice job wyz2285 and yay for syringe metering
Posted: Sat Mar 12, 2011 3:24 pm
by wyz2285
The pvc tube are a self close type, they have a rubber ring in the inside, so i don't have to glue them, only need use few screws to make sure they stays together . Ya the syringe looks like the easiest way to inject fuel to me so i used it
Posted: Sat Mar 12, 2011 3:34 pm
by Labtecpower
I wouldn't trust the self-sealing types. I have seen them at the local DIY store
(GAMMA!)
a few years ago (when I wanted to make the same type of gun )
They are pretty thin-walled.
Also, do not underestimate the amount of force applied to the caps and screws. A combustion gun generates about 6 bar (kg/cm 2)
There are several vids on youtube with guns of this type exploding.
But: the gun itself looks very good. It looks clean, and well constructed. (apart from the used material )
I'd like to see a gun constructed with proper materials. keep em coming!
Posted: Sat Mar 12, 2011 5:16 pm
by wyz2285
Can you show me some of there videos ? I have chosen these pvc tubes because a friend of my build one using them and worked out very well.
Anyway I'm still looking for metal tubes so...
And these tubes aren't thin-walled, i think so, the wall has 5 mm, looks strong
Posted: Sun Mar 13, 2011 1:17 pm
by jrrdw
If you used ' Krylon Fusion' or a 'adhesion promoter' the paint will stick good. If not it will start flaking off.
Posted: Sun Mar 13, 2011 1:30 pm
by Labtecpower
[youtube][/youtube]
This PVC is about as strong as yours, I think.
Posted: Sun Mar 13, 2011 1:44 pm
by jakethebeast
i think that was white pvc...
Posted: Sun Mar 13, 2011 2:00 pm
by Labtecpower
White pvc is exactly the same material as grey pvc (except from the color )
I've had an end cap blow off like that before. Good thing I wasn't stupid enough to put the ignition source in it though
On paint, I've never had paint "flake" off of cannons before. I use Rustoleum professional enamel spray. It coats well and doesn't come off unless you actively try to remove it.
Posted: Tue Mar 15, 2011 5:18 pm
by motorfixer1
Nice, clean looking launcher, still made out of plastic though.
Posted: Tue Mar 15, 2011 6:18 pm
by mark.f
motorfixer1 wrote:Nice, clean looking launcher, still made out of plastic though.
.
, 
, but I really consider that´s not safe enough. Any way, I finished it and fired it 5 time till now 
.
. Ya the syringe looks like the easiest way to inject fuel to me so i used it 
)