Had another idea...

[bomar76]

Re: Had another idea...

231 cubic inces in 1 gallon..... standard air pressure is around 14.696 PSI (that's what we inhale)

231 x 55 gal = 12705 cu inches and each cubic inch at 100 PSI (at almost 7 times the standard atmospheric pressure

What you will have is a BOMB!

In other words..... bad idea.

There are so many things wrong with this post......

 

[bomar76]

Re: Had another idea...

Some quick numbers for you SgtMaj.................The Diameter of a 55 gal drum is aprox. 23 inches, the surface area of said diameter is around 415 sq. inches. now multiply that by 2 (for the top and bottom) and you have 830 sq inches. Now add 100 Pounds per Square Inch and you have a load of 83,000 pounds, half of which is pushing at the top while the other half pushes at the bottom. Now lets add in the sides of the drum. A 34 inch tall drum with a 23 inch diameter has a wall surface area of around 2456 and 3/4 inches. Adding our 100 PSI we now have a Side load of 245,675 pounds. Thats a lot of load.

and then we have the correct information....

 

[SgtMaj]

Re: Had another idea...

At a local shipyard down here they were testing a newly completed tanker river barge. The barge had to hold 1 psi for some amount of time don't really remember. There was a pressure relief valve that was set at just above 1 psi, the valve was a steel flapper on a pipe sticking out of the deck. They started filling the barge with air and waited and waited and waited until... BOOM!

Someone had put something on top of the flapper valve, the pressure had soared () to 2 or 3 psi and the side of the barge was blown out.

As far as the math is concerned assuming the drum is full of fresh water, water pressure = density x gravity x depth

Total pressure = Water Pressure + Atmospheric Pressure

Density of Fresh water = 62 lb/ft^3
Gravity of Earth = 32 ft/s^2
Depth of 55 gallon drum = 3 ft
Atmospheric Pressure = 14.7 psi

Water Pressure experience by the bottom of the drum = 41.33 psi

Total Pressure experienced by the bottom of the drum = 56 psi

The water pressure is directly related to the depth of the water, so halfway up the drum there is only about 36 psi.

Basically the drum would never come close to experiencing 100 psi under normal operation.

So... by this... are you saying that I also shouldn't stack the two drums together to make a 110 gallon rain barrel as I was planning to originally?

 

[bhammer]

Re: Had another idea...

We put an empty drum bottom down on a passenger air bag and set it off. Sent the drum up about 30' no problem. What a great site. The only problm.... Where the heck to run when it reached max altitude and started down.

 

[Coors]

Re: Had another idea...

Forget that, still time to make a tater gun for the 4th.

 

[dave11]

Re: Had another idea...

Love the duct tape idea.LOL

 

[kenmyfam]

Re: Had another idea...

Only just saw this thread for whatever reason.
You can do as many calculations as you like on this one, right, wrong, whatever. The bottom line is,
It is a major accident waiting to happen. Do Not Do It.
So glad you asked the question before starting the project though.

 

[rolmops]

Re: Had another idea...

Blah blah blah.
Nothing will explode.Because long before the pressure can be brought up that high either the cap will fly off or a lengthwise tear will open up probably on the seam.
If you want it to explode and give of some spectacular sound and very orange light and smoke,fill it up with a mix of 50/50 gasoline and diesel fuel.You may wish to add, say 30 pounds of sugar in the mix so it will have a bit of a napalm character added to your explosion.Hang this off a pole and ignite a fuse.FROM A VERY SAFE DISTANCE!!!!

 

[Bigprairie1]

Re: Had another idea...

Blah blah blah.
Nothing will explode.Because long before the pressure can be brought up that high either the cap will fly off or a lengthwise tear will open up probably on the seam.
If you want it to explode and give of some spectacular sound and very orange light and smoke,fill it up with a mix of 50/50 gasoline and diesel fuel.You may wish to add, say 30 pounds of sugar in the mix so it will have a bit of a napalm character added to your explosion.Hang this off a pole and ignite a fuse.FROM A VERY SAFE DISTANCE!!!!

.....I'm in.
BP

 

[oops!]

Re: Had another idea...

heh heh heh......

jackie gleasons saying........"ya wanna go to the moon"....keeps coming to mind.......


mythbusters did a bit on a hot water tank. at approx 300 psi, it went thru a roof of a mock house, and a few hundred feet in the air.....really cool footage.
the mock house was totally destroyed......flattened....leveled.....ripped apart.

you could see peices of splintered, short 2x4, exploding thru the top of the roof.



now......if they would have used duct tape.....

 

[Nandy]

Re: Had another idea...

Even if the barrel was to hold I cant imagine the motor of the compresor will last too long having to work in a load 100 times larger than the original.

 

[kenmyfam]

Re: Had another idea...

Even if the barrel was to hold I cant imagine the motor of the compresor will last too long having to work in a load 100 times larger than the original.

Good point, especially as it has a 1 gallon tank currently !!!!

 

[jay_merrill]

Re: Had another idea...

So you're saying it's still a good idea... but I should hook it up on July 4th, turn on the compressor, and stand back, WAY back? OK, will-do.

Thanks for pointing out my err though... Will probably still try it, but will take safety precautions now.

Dude, sometimes you just scare me! Now, repeat after me ..... "step away from the whacky ideas!"

 

[thefairlaneman]

Re: Had another idea...

Dude, sometimes you just scare me! Now, repeat after me ..... "step away from the whacky ideas!"

I say " step away from the whacky weed" gezz

 

[SgtMaj]

Re: Had another idea...

Blah blah blah.
Nothing will explode.Because long before the pressure can be brought up that high either the cap will fly off or a lengthwise tear will open up probably on the seam.

My thought exactly... hence the reason I'm still going to try it, well that, and the fact that I still think it'll take 100psi... it's not like 100psi is all that great... now if it was a 200psi compressor... well no way.

If you want it to explode and give of some spectacular sound and very orange light and smoke,fill it up with a mix of 50/50 gasoline and diesel fuel.You may wish to add, say 30 pounds of sugar in the mix so it will have a bit of a napalm character added to your explosion.Hang this off a pole and ignite a fuse.FROM A VERY SAFE DISTANCE!!!!

...or... not. And Jay says I scare him??

 

[Bondo]

Re: Had another idea...

insisted against the opinions of many here, that making an air compressor tank from a gas propane tank was a great idea.

Ayuh,.... That Does Work,... I've done it Many times,+ still use a 100lb.er for added reserve Now....

hence the reason I'm still going to try it, well that, and the fact that I still think it'll take 100psi... it's not like 100psi is all that great...

Ayuh,.... You Really Don't understand Anything about Pressurized Air,... Do You.?...?.

10psi is Not very much,.....

100psi is More than enough to Kill you.......

Pressure vessels have Rounded ends,+ No Corners such as at the top,+ bottom of a 55gal. Drum.....

It's at the corners where it'll Explode from....

 

[beerfilter]

Re: Had another idea...

Thats an expensive show , with fuel prices these days .
An Oxy/acetylene torch setup and some balloons is far cheaper , and , doesn't incinerate everything within 100 yards .

Forget fuses , get a model rocket ignition system , or , just get a set of igniters , a car battery , and some really cheap speaker wire .

BEWARE of static discharge , it can ruin your day , maybe your life .
This stuff is EXTREMELY powerful , not quite HE , it can still do massive damage if mishandled .

4 average sized party balloons are sufficient to completely shred those big Rubbermaid industrial trash cans , you won't find a piece bigger than 1" usually .
It will also set off car/burglar alarms for a half mile radius .

I once did an improvised show at a party .
Having nothing else to contain the blast , I used 4 car tires .
A 20' length of pvc , bottle rockets , and , extra fuses from packs of firecrackers for the ignition system .
We sent someone to town for balloons .

I placed the pvc pipe between the first and second tires .
I then placed some 1/8" thick veneer ply that was laying around , on top of the third tire , placing the 4th tire over that .
This after loading with 4 balloons of the O/A mix .

Ignition was achieved by placing a bottle rocket in the pvc , tying a length of extra fuse to the rockets existing fuse , and , placing the end of the extended fuse on a lit cigarette for some extra time to get to safety .
Rube Goldbergish . but , effective .

This redneck rig produced almost a dozen earthshaking blasts before we could no longer locate the 4th tire .
The 4th tire was found a week later , 70' up in an Oak tree .

 

[angus63]

Re: Had another idea...

Even if the barrel was to hold I cant imagine the motor of the compresor will last too long having to work in a load 100 times larger than the original.[/quote



Nandy, that same compressor could fill the Hindenberg to 100psi and not experience any more "load" than the one gallon tank it is filling now. The only difference would be the length of time the compressor would operate at the same load until the volumetric difference was made up. Fluid power is very deceptive. Ten psi is dangerous. Ten psi in a six inch cylinder will lift your 275lb mother-in-law easily. Pressure vessels are seamless and rated at appx 75% of their calculated allowable stress. "Hoop stress" in a pressure vessel is (press x rad / thick). If a vessel was seamless and had full spherical ends, a 30" dia barrel that was .06 thk made of steel with a tensile yield strength of 30,000 psi would be rated as follows:

Rated psi = thk x (allow. stress) / largest radius
PSI= .06 x (75% of 30ksi) / 15
Rated PSI = 90​

a 55 gallon barrel that is flat ended, sealed by coining and not welded, and chock full of discontinuities would not be rated, but as stated many times, fun to watch go boom from a safe distance!​

Spent many years designing pressurized aerospace heat exchangers and the engineer nerd in me is overpowering and escapes often.​

 

[SgtMaj]

Re: Had another idea...

Even if the barrel was to hold I cant imagine the motor of the compresor will last too long having to work in a load 100 times larger than the original.[/quote



Nandy, that same compressor could fill the Hindenberg to 100psi and not experience any more "load" than the one gallon tank it is filling now. The only difference would be the length of time the compressor would operate at the same load until the volumetric difference was made up. Fluid power is very deceptive. Ten psi is dangerous. Ten psi in a six inch cylinder will lift your 275lb mother-in-law easily. Pressure vessels are seamless and rated at appx 75% of their calculated allowable stress. "Hoop stress" in a pressure vessel is (press x rad / thick). If a vessel was seamless and had full spherical ends, a 30" dia barrel that was .06 thk made of steel with a tensile yield strength of 30,000 psi would be rated as follows:

Rated psi = thk x (allow. stress) / largest radius
PSI= .06 x (75% of 30ksi) / 15
Rated PSI = 90​

a 55 gallon barrel that is flat ended, sealed by coining and not welded, and chock full of discontinuities would not be rated, but as stated many times, fun to watch go boom from a safe distance!​

Spent many years designing pressurized aerospace heat exchangers and the engineer nerd in me is overpowering and escapes often.​

Just to clarify something... they are plastic barrels, not metal. Not that it makes much difference, but I don't know where to get metal drums for free, so it makes a difference to me.

 

[angus63]

Re: Had another idea...

Just to clarify something... they are plastic barrels, not metal. Not that it makes much difference, but I don't know where to get metal drums for free, so it makes a difference to me.

Plastic shrapnel probably won't damage the house next door!!!! Pressurizing anything with a gas that is not rated is a poor choice