Safety of malleable iron

[nivekatoz]

If you capped off both ends of a sch 40 black iron pipe and filled it with black powder ,the caps will blow off and strip the threads before the pipe bursts..I have seen solw motion viedo of this.. On the other hand, I don't know how much powder was used..But still it looked powerfull. Im no expert.

[tyrant_bb]

DYI: Well, you said 1/2" steel coupling...but then you said malleable iron (or same thing?)...anyway wow that makes me feel a lot safer.

nivekatoz: Are the endcaps made of malleable or black iron?

This is unrelated, but if I wanted to drill a hole for 1/4" NPT fitting, what size would I drill?

[frankrede]

i say this once again.

a soda bottle can hold 150psi. then you think of the wall thickness and the soft plastic used in them. do you trust the fittings for 14.6 as high burst pressure as the bottle? (they also has less surface area aswell as the double wall thickness when something is threaded into or outside them)

According to your logic, then cell core abs is a great material to use in pneumatics!

[tyrant_bb]

Haha I heard that, but I actually tried this with a 2 liter soda bottle...I used a pop in schrader valve and sealed it with epoxy. At 60 psi, the bottle rips around the valve and flies across the room. Probably some mistake I made though.

[DYI]

According to your logic, then cell core abs is a great material to use in pneumatics!

How's that? Cellular core pipe is full of air bubbles, so you can't apply the same guesstimates that you can with a solid material.

The coupling I mentioned earlier was malleable iron, just to clarify. I tried the same setup earlier with black powder, and it held together just fine, although I still wouldn't want to be within a hundred feet of it when it went off.

[SpudFarm]

i think all the "magic dust" talk should be stopped here before someone get a nice slap by a mod.

frank: cell core is just fine for everything. if you don't put more pressure in it than 5psi.

one more note about this. you know these balls? i bursted one and it held up to 65psi.

[Gippeto]

Some information about iron. There is a table lower down which gives tensile strengths.

Why guess when you can know?

http://en.wikipedia.org/wiki/Cast_iron

[SpudFarm]

i can't have done that right..

[Gippeto]

Your wall thickness seems too much. I prefer to use the thinnest section when calculating burst/yield pressures.

Usually the wall thickness at the deepest part of the thread.

[SpudFarm]

but the threads helps also. (i may did it wrong since i usally uses mm)

[Gippeto]

I don't know about the fittings and pipe that you have in Norway, but the stuff I use still leaves more than one thread to atmosphere when tightened.

That makes it the thinnest section, and the thickness to use for calculations.

You are ALWAYS better to err on the safe side.

.2" = 5.08mm

[SpudFarm]

i messure my fittings tomorrow

[frankrede]

According to your logic, then cell core abs is a great material to use in pneumatics!

How's that? Cellular core pipe is full of air bubbles, so you can't apply the same guesstimates that you can with a solid material.

The coupling I mentioned earlier was malleable iron, just to clarify. I tried the same setup earlier with black powder, and it held together just fine, although I still wouldn't want to be within a hundred feet of it when it went off.

Cellcore abs is actually 2 thin layers of plastic, not to different than the plastic of soda bottles, and might even be stronger with a hard foam core.

[Maniac]

ne more note about this. you know these balls? i bursted one and it held up to 65psi.

Is that true, my dad is a personal trainer and he has like 5 of those balls ghetto pneumatic award here I come.

[SpudFarm]

yeah it is true but it gave a pretty decent bang and blew the grass away.

and don't use it over 20psi since it can burst when you touch it.