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8" SCH 40 steel pipe - ideas?

Posted: Thu Apr 10, 2008 4:49 pm
by DYI
I found a 3 foot long chunk of 8" SCH 40 seamless steel pipe at the welder's, behind the shop. He'll give me the whole thing for $30 or so if I want it, as it's just an offcut. They had 8 feet of SCH 40 12", but apparently it was already bought :cry:

The thing is, it's too weak to be used as the chamber pipe for my 100mm BFG, and I already have 2 prototype hybrids in the works (a SCH 40 4" one to test fueling, and later a SCH 80 seamless 4" one to test ignition).

Any ideas as to what to use it for would be appreciated, provided that they don't include burst disks. Even a butterfly valve may end up being used, as my budget for this summer will be largely consumed by the BFG, and I want a gun I can shoot for fun that doesn't have pathetic power. A 4x piston hybrid may be considered, but building a serviceable steel piston valve from welded parts doesn't sound like a very pleasant endeavour.

If everyone submits their ideas, I'll make a poll including the most popular ones in a few days. The winning option, assuming that it isn't impossible or horribly expensive, will be built.

Posted: Thu Apr 10, 2008 5:09 pm
by Sticky_Tape
Just today I know it wouldn't be good for a hybrid but anyway My friend Mikey has 10 ft lenths of sch 40 3'' galvanized steel pipe his father has a construction company that he got them from I think he has 9 10 ft lenths.

Posted: Thu Apr 10, 2008 5:13 pm
by SpudFarm
if you want big diam REALLY thick walled steel pipes up to i think 12" i know the perfect guy for you! Larda!

why not make a 500psi piston pneumatic with a 4" bore?

Posted: Thu Apr 10, 2008 5:28 pm
by DYI
It would be good for a hybrid, but I've already got three in progress, which is why I want other ideas.

And as I said before, welded steel piston valves aren't the greatest idea - complex, difficult to design, and essentially unserviceable.

Posted: Thu Apr 10, 2008 5:31 pm
by bigbob12345
I say a very large 500psi coax :roll:
with 3in or 4in bore

I know you said you didnt want a piston valve....

Posted: Thu Apr 10, 2008 5:39 pm
by Sticky_Tape
burst disk gun

Posted: Thu Apr 10, 2008 5:47 pm
by DYI
Any ideas as to what to use it for would be appreciated, provided that they don't include burst disks.
building a serviceable steel piston valve from welded parts doesn't sound like a very pleasant endeavour
Gee, have you ever considered reading the f*cking topic? I'm trying to get useful ideas here, not to clog up PCGUY's bandwidth with useless posting.

Posted: Thu Apr 10, 2008 6:09 pm
by jrrdw
DYI wrote:It would be good for a hybrid, but I've already got three in progress, which is why I want other ideas.

And as I said before, welded steel piston valves aren't the greatest idea - complex, difficult to design, and essentially unserviceable.
Depends on how you build it, and your budget. I read a story about a guy went to a shooting range, drug a big fat piece of pipe and some bowling balls out of his car trunk. Used a camping shovel to dig a hole and buriered it half way. Inside the pipe was a little cup for the propelent. Fill the little cup, drop in a bowling ball, fire the cannon/morter. It was said to shoot a ball 1500 yards/meters. It been a while since I read it, don't quote me.

Posted: Thu Apr 10, 2008 6:22 pm
by DYI
The problem is, this pipe is SCH 40 - black powder would blow it to bits on the first shot. I really wouldn't trust this pipe at anything over 1 000 psi or so.

And just FYI, the budget for this project is VERY low - under $200. So nothing too fancy.

Posted: Thu Apr 10, 2008 6:32 pm
by TurboSuper
Eh, who says you need to make a cannon?

Fill it with water and use it to lay sod :D

Posted: Thu Apr 10, 2008 9:57 pm
by THUNDERLORD
I would like to see you build a recoiless hybrid and use that pipe for the chamber similar to my design here:
http://www.spudfiles.com/forums/my-proj ... 13859.html

I would help with ideas and it would be your hybrid design.

That would be Cool!!!, The biggest shoulder fired hybrid ever!!!

Posted: Thu Apr 10, 2008 11:39 pm
by MrCrowley
DYI wrote:The problem is, this pipe is SCH 40 - black powder would blow it to bits on the first shot. I really wouldn't trust this pipe at anything over 1 000 psi or so.

And just FYI, the budget for this project is VERY low - under $200. So nothing too fancy.
THUNDERLORD wrote:I would like to see you build a recoiless hybrid and use that pipe for the chamber similar to my design here:
http://www.spudfiles.com/forums/my-proj ... 13859.html

I would help with ideas and it would be your hybrid design.

That would be Cool!!!, The biggest shoulder fired hybrid ever!!!
:roll:

Who says this piece of pipe has to be a chamber anyway? I know the flow restriction would be crazy, but it could be fun as a barrel :)

Posted: Thu Apr 10, 2008 11:44 pm
by jook13
Who says this piece of pipe has to be a chamber anyway? I know the flow restriction would be crazy, but it could be fun as a barrel
not much flow restrictions if the chamber is even larger eh?


And to the original poster, I am guessing you are not to keen on a nice advanved combustion? with an eight inch chamber it could be one of the most powerfull combustions on the site.

Posted: Fri Apr 11, 2008 12:11 am
by THUNDERLORD
@ MrCrowley, yeah it would make a great barrel but it's only 3 feet long he said.

For my design/concept, that would put the concussion of the muzzle blast too close to the firer's face.

And if it's not recoilless It would be hard to shoulder fire if it had close to it's potential.

I am working on mathmatic formulas/ testing to see about using a smaller diameter pipe on the back of the muzzle but with a heavier counter shot.

So the 8" pipe could still be the entire muzzle, just with a smaller pipe out the back.

But that's stuff we could discuss if he decides to build a recoilless.
And " largest hybrid ever shoulder fired "

Posted: Fri Apr 11, 2008 1:54 am
by MrCrowley
THUNDERLORD wrote:@ MrCrowley, yeah it would make a great barrel but it's only 3 feet long he said.
Good point :)