SpudFiles

I am going to be building a hybrid soon and I picked up a piece of steel pipe today to use for the chamber, I am looking at maybe a 5x -10x hybrid and I do not know if this piece of pipe will handle it here is the specs the inside diameter is 105mm and it's got a 5 mm wall thickness now I am wondering if this will be good enough or if I need to find something a bit more beefy

If there is a thread discussing this please point me towards it cause i tried the search but I must be using it wrong cause I did not find anything useful

Thanks
Heimo

With those numbers the answers we can give you will be as accurate as cold reading.

How is the pipe formed? Does it have a seam? Is it drawn? Is it welded? Is it annealed? What temper is it rated to? What alloy? How are you going to attach the gun together?

105mm Is a rather large chamber size for that mix hybrid, it's a lot of energy to be toying with. When you have some numbers on the pipe it can be run through a pipe burst pressure calculator then you can find an appropriate safety margin.

inonickname wrote:With those numbers the answers we can give you will be as accurate as cold reading.

How is the pipe formed? Does it have a seam? Is it drawn? Is it welded? Is it annealed? What temper is it rated to? What alloy? How are you going to attach the gun together?

105mm Is a rather large chamber size for that mix hybrid, it's a lot of energy to be toying with. When you have some numbers on the pipe it can be run through a pipe burst pressure calculator then you can find an appropriate safety margin.

actually i have no idea how it's been formed I guess that is bad I got this piece of pipe from the scrap yard it is my favorite store to shop at I cannot find a seam on it but that does not mean that it ain't there it could just be hiding under a very thin layer of surface rust note it ain't rusted enough to affect the integrity of the pipe

I plan on plugging the rear end of the pipe with a disc of 7mm thick steel welded to it, my welding is good enough that I can make a gas tight weld on a piece of pipe I weld with a stick welder and stick welders penetrate deeper then say tig welders as far as I know, but if this is a bad idea I would find a different way.

maybe I should aim a little lower with this unknown pipe say a 0X-4X hybrid ? does that sound a little better?

Still a little hard to say.

It can be welded, though you'll lower the rating of the pipe by annealing it. Make sure the world is very strong. If you think it isn't good enough, do it again.

How the pipe is formed will be a big wildcard. Sand a short ring inside and out to see if there's a seam (look VERY closely).

If you don't have accurate safety figures on the material, don't be anywhere near it when it's armed (and fired).

since I actually want to make a hand held cannon I think I will try to find some other pipe I recall seeing a 50mm diameter pipe laying someplace with a very thick wall about 10mm I think next time I visit the scrap yard I will be grabbing a piece of that cause I am certain that that kind of pipe will be strong enough
the reason I don't just buy a known piece of pipe is; the hardware stores are pathetic over here the people that work in 90% of all the hardware stores and steel places are just plain idiots and their stupidity ticks me off I once asked a guy if they carry seamless pipe and he asked what's that is I told him there is no seam in the pipe and the pipe is made for higher pressures he said Oh i think we have some and then he pointed me at some pipe when I checked it was the normal welded pipe I think I am going to look for a better piece of pipe before I make something dangerous to fire

Your best bet is to clean off the pipe and inspect it. If something that big blew up at 10x and you where anywhere near it there would be hell to pay. I have a straight combustion with a 50'' long chamber 6.25 inches in diameter. I use a 15' long and 3'' wide barrel to launch 16oz canned goods and a 6' long 4'' barrel to launch 40oz JIF peanut butter jars. Yesterday i shot a peanut butter jar full of ice. I missed my target and backdrop, overshooting by a few inches and slammed into my steel shed. The jar went straight through making a basketball sized whole and slammed into an old tractor loader jarring it. My point is make sure you are really comfortable making such a gun because at 3x the gun you are trying to make should be able to make some serious power.

Edit: good thinking. Safety first