Stainless Steel Hybrid

[Scotty]

Hey spudders, has anyone got any idea how much pressure Stainless Steel cylinders can hold.
I have a 100ci cannon that is a simple combustion setup- however i am going to turn her into a Hybrid.
It has 2.0mm wall thickness plus an internal sleeve of polyurethane about 5mm thick.
I would like any ideas of what x (fuel air mixture- 14,28psi.etc) would be considered "safe" for this Steel hybrid.
The barrel is about 1/8 thick Aluminium and 34mm i.d.
I would like to think that anywhere in the order of x4 or 5 might be sufficient fun, however if anyone thinks this is over the top please let me know, flying P.V.C. is one thing-flying Steel is another!!
I will be using Butane for fuel and anything up to and including 250grms in weight as a projectile.
Any ideas would be greatly apprieciated. Thanks in advance

[chaos]

hey you my kind of guy,

questions:

what grafe of stainless?
what O-D?

im doing a very similar task/project to what you are doing wanna have a lil contest?

[Scotty]

Hey Chaos thanks for the reply, the grade is 316 and the o.d. is 4" the length is roughly 10".
The end plugs are made from Nylon (super thick, no chance of malfunction there.) And yes a bit of competition never hurt anyone, i'm in!

[chaos]

haha sweet,

well,

Theoretical burst pressure of 4" S/S tube with 2mm wall thickness:

-3038psi burst

and...

Theoretical working pressure of 4" S/S tube with 2mm wall thickness:

-646psi working.

there ya go!

so yer im building one similar but with 3" for it has a higher pressure rating oh how long is ur barrel gonna be?

i don't really know about the X'factors yet im still researching

peace
~chaos

[Scotty]

That is some very useful info there Chaos, thankyou muchly.
My barrel will be to suit a c:b ratio of 1.5 to 1 me thinks about 5 or 6 feet should do the trick.
That means i should be researching burst discs of around 500psi, would you agree with that?
Somewhere around 900fps muzzle velocity is what i'm hoping for, i don't want to break Mach 1. Spud guns are not quite legal where i live. I will have to go into international waters just to fire the thing!

[chaos]

R u in australia like me? lol yer i cant wait to get it done.. aye what ignition are ya gonna use? me thinks i might have to use a flyback transformer or sumthing, but maybe my peizo will do the trick,

oh and do you have any good web pages on hybrid fuel mixtures ect Wiki wasnt much help

[Scotty]

Yup me a fellow oi oi. I will use piezo with a special "lance" to goes up the bum of the chamber( it's made into the nylon end plug) Don't know of any sites about fuel mixtures. Have you heard of Methyl Ethyl Ketone? It's an organic thinner used in fibreglass manufacture and works real good in smaller guns, maybe a mix of that and pro/butane might work well... You probly just need a chamber fan to evaporate the M.E.K.
Got to go to work now i'll try and post some pictures of the "old" cannon- It looks super slick! even if i do say so myself and well i do!

[ShowNoMercy]

Do you use a aerosol for that stuff?

[sandman]

why would an organic thinner be in a aerosol?

wait what is an organic thinner?

[ShowNoMercy]

no no I mean like using an aerosol nozzle to inject the thinner.

[sandman]

oh oh, i feel stupid now
so i think ill leave this thread as i have never built a hybrid

[ShowNoMercy]

Lol you know you wanna.

[sandman]

oh, i have plans but first i think i will get my pneumatic and combustion done first and more money

and scotty sry for spamming thread, good luck, and i am intrested in yuo ignition system

[veginator]

YOU F***ING MORON! Do you even know what kind of power is in that blast?! You'll be blown to pieces!! :withstupid:

[paaiyan]

YOU F***ING MORON! Do you even know what kind of power is in that blast?! You'll be blown to pieces!! :withstupid:

Uh, which blast?