Pressure rating...

[deathbyDWV]

So... While designing a high(er) pressure piston cannon, similar to jeepkahn's decimator, I've been thinking about metal (black and galvanzed steel) pipe. I've only heard about their pressure rating to be 150 psi. BTW I'm talking about the kinds sold at lowes...

What I'm wondering is, what pressure would 2" black or galvanized steel be relatively safe to use at?

Thanks in advance...

P.S.-- I did search, but there are so many posts that include pressure rating, I couldn't find anything...

[theBOOM]

Well you might want to search for DYI's cannon, I believe he used off the counter hardware parts for most of his cannon and he took it up to about 20x mix. Let me find you the link.

http://www.spudfiles.com/forums/me20h-4 ... 14452.html
There ya go

O and he uses 2in fittings on it.

[deathbyDWV]

Oh yeah, I didn't really think of his... So mine probably won't explode, but would be unsafe at higher pressures though... I'm thinking of co2 but I don't think I'll go for high pressure if these fittings can't take it. Maybe use co2 and just go to 200 or so psi...

[kjjohn]

This question has been asked before - I asked it.

The responses I got were that it could hold well above 150psi, more in the range of 1kpsi, and as theBOOM stated, DYI's cannon was constructed of standard fittings, and I believe he even used a plastic barrel. Pressure ratings usually use somewhat high safety factors, and in reality, the material can usually withstand significantly more pressure, even an order of magnitude more in some cases.

So yes, 2" galv will definitely hold the amount of pressure you need it to. The only concern I would have is that it may be hard to make a piston with the seam in the pipe, but I'm sure you've taken that into account, and it can easily be sanded out.

[spudtyrrant]

The only concern I would have is that it may be hard to make a piston with the seam in the pipe, but I'm sure you've taken that into account, and it can easily be sanded out.

in some cases, such as the galvanized at true value, it is seamless on the inside

[deathbyDWV]

The only concern I would have is that it may be hard to make a piston with the seam in the pipe, but I'm sure you've taken that into account, and it can easily be sanded out.

Yep, i did think of that...

in some cases, such as the galvanized at true value, it is seamless on the inside

Thanks, I'll keep that in mind...

Thanks for the replies guys... 8)

[Crna Legija]

btbs Mr.Porter made out of 2inch galv and he took it to 500psi

[deathbyDWV]

Ah yes, and that was three inch... So I think I'll be fine... Thanks for the link!!!