SpudFiles

hey i think i am going to buy a 3" barrel for my hybrid but if i am going to buy 15foot of galvanized i get ruined...

then i wonder if you think i can use a 3" exhaust pipe. it has aprox 1mm thick walls.

and do you think it is any chance to get any velocity with a 2" union?

That exhaust pipe is seamed (bad), thin, and is bendable so it can be shaped to fit different cars.

It would probably be ok for a combustion but anything more powerful than that, I dont know.

Another pipe very similar to 3" exhaust pipe and cheaper would be thinwall EMT conduit pipe for electrical work.

But I've never used either one.

If you want to get it up to full power AND being safe , you should spend the money on the galvanized pipe....
Its a big investment, but it may be worth it.

hmm.. then i guess i am stuck at 2"

I've run into a similar set of problems as spudfarm in the barrel category; for the 20x hybrid I'm going to build, there isn't any readily available material that can be used as a barrel in over 1" diameter around here, other than 4" steel. Now 4" steel is great for big, slow, heavy rounds, but for penetrating capabilities I'd be looking for 2", which I can't obtain without spending very considerable amounts of money.

And of course, length always kills the thing. To cure that problem, you need more pressure, and more pressure gets difficult eventually, whether you use flammable gases or other things to generate it.

In your case spudfarm, could you try reinforcing the exhaust pipe by casting something with a high tensile strength around it? I did that with a 1.5" ABS pipe inside a 3" ABS pipe, with fiberglass resin in between. Testing at 10x should be possible in a month or so, because some parts need to be ordered, and safety testing needs to be done on a new system I'm working on.

mabe some wet fine grained sand with water in it?
and if i am going to get the pipe on the outside i could have bought 3" galvanized in the first place..

if i am lucky larda has some 3" for a nice price