I borrowed some landscaping tools from my brother in law and he offered his old air compressor since he doesn’t use it. Broken tube. Easy normal part to replace.
Got a air compressor accessories kit on the way home. Replaced the hose and tip. Plugged it in outside. Left it for 10 minutes…
Never turned off. Hmm. Might be one of those that have a release valve and not auto shutoff.
20 PSI? That’s odd. Unplugged it. Hissing…
Air coming out the bottom. Maybe a puncture?
Found the spot. Got 80 grit sandpaper and 3300 PSI rated epoxy. Sanded and found rust.
Patched it and my spidey sense went off while looking at the epoxy…
Did a search:
A leaking air compressor tank—especially with a leak on the bottom where corrosion is likely—can be extremely dangerous, even if “repaired” with epoxy or other sealants. The primary risk is catastrophic rupture under pressure. If the integrity of the tank is compromised (for example, by internal rust or a patched-up hole), the tank can explode with explosive force, launching shrapnel and causing severe injury or death, as well as property damage
When tanks rupture, the velocity of air and shrapnel can be lethal. For example, a 60-gallon tank at 150 PSI can explode violently, creating 680 mph air blasts and extremely loud noise, both of which are highly hazardous for bystanders
Nope! Tossing it!
Dodged a nearly literal bullet there.
Bonus shots:
Flex tape baby 😎
You’re really overestimating the force of a home compressor. I’ve seen 2500PSI tanks rupture. Those will kill you
Yeah. At the union hall where I got my structural steel welding cert, there was a whole yard of “don’t do this shit” that they walked the class around. Almost all of the examples had killed someone too. There was a whole section on definitely do not compress liquids in random dumb ways. I don’t remember the details but there was a box like a custom made toolbox for a pickup truck that someone had built square tanks into and was doing something like a service truck transferring fluids to heavy equipment. It wound up blowing apart catastrophically and killed more than one person. They did the investigations at that hall so they had a the bad stuff already and had to keep it for a designated amount of time for legal reasons.
Air is not super duper dangerous like any kind of fluid. Fluid is what will get you, and that compressor will have fluid in the bottom, so it can get you.
That was my main take away from structural steel; compressed fluids = xrays + engineer & with no exceptions.
The fluid is not what will kill you. The shrapnel will. The metal vessel is far more dangerous than than any fluid that will be in it
Air is dangerous as well. A hydraulic system quickly loses energy on failure because oil is nearly incompressible.
Compressed gases or liquids that are beyond their boiling point at atmospheric pressure store a lot more energy at pressure and release it a lot more violently than hydraulics when experiencing a surprise decompression.
Let’s take a 100 liter compressor tank that’s buffering at 10 bar:
For an isothermal expansion from high pressure to atmospheric pressure, the energy is:
E = P₁V₁ ln(P₁/P₀)
Where:
P₁ = 10 bar = 1.0 MPa
V₁ = 100 liters = 0.1 m³
P₀ = 1 bar = 0.1 MPa (atmospheric pressure)
E = (1.0 × 10⁶ Pa)(0.1 m³) ln(10)
E = 100,000 J × 2.303 E = 230,300 J (or about 230 kJ)
TNT releases approximately 4.6 MJ/kg of energy. 230,300 J ÷ 4,600,000 J/kg = 0.05 kg or 50 grams of TNT
Of course a tank rupturing will expand a lot slower than TNT, but the energy is the same and when half of the tank shell points towards some offices next to the workshop, the first three walls will be impressed pretty much the same way by the suddenly very agitated piece of steel.
Had an air tank fall over in a stupid way during refilling at our local fire station last year. Valve broke off at nearly 270 bar and the thing went off. Now there are new rules, new indents in the concrete walls and at least one fireman that reacts a bit jumpy to “clang” like sounds.
I think they just blanked for a moment and forgot air was a fluid. Pressure is crazy dangerous in all forms. Insert peer pressure joke
Big agree. Air can scare. Steam is worse because of condensate.
you sure the high temperature and thermal mass of steam isn’t slightly worse than condensation?
If you are going to repair something like this, always do a hydrostatic test to twice working pressure. It’s the only safe way to check for failure. But throwing it away was almost certainly the right choice here.
100% agree on tossing it. The risk isn’t work it. I think the only thing I’d do differently is to stab that hole to make it larger, as a way of indicating to any would-be dumpster diver: “you really do not want this”.
I have a similar policy for CAT6 cables, where if I’m tossing it due to diagnosing that it’s dead, I’ll cut it in half. The next person who wants to revive it is now on-notice that it might have problems.
Same policy for faulty home appliances: the cord gets cut off.
I would use it to test how much destruction it could unleash. Maybe bury it in a pile of sand or in ground. Set a long line to. Start it. Overpressure it. Wait.
But completely agree. It is unsafe. Do not use it.
If OP records it for viewing online, then it’s not dangerous, it’s science.
Mythbusters would be proud.
I agree that using this tank would be unsafe…
But now that you’ve mentioned that specific test regime, the seeds of a bad idea have been sowed lol. So to that end, I have to advise anyone who even thinks to try that: make sure you have a way to de-pressurize the suspect vessel, not because the tank would fail, but because it might pass.
Because if it actually achieves 100% of working pressure and you keep climbing but it still hasn’t failed… what do you do then? Just leave it there in the ground with over pressure? It would essentially be a hidden landmine, waiting for water corrosion to take its toll and set it off. And no one is going to get anywhere near a potentially-damaged pressurized vessel at over 100% working pressure, not without body armor.
This is definitely Mythbusters territory now.
The first thing coming to mind would be setting up an automatic pressure release valve. I’ve seen those used to do pressure tests on pipes. It would facilitate making small increments to the maximum pressure admitted.
For all we know, the tank may very well rupture when put to less than maximum normal service pressure
Happy, that you dodged that bullet, op!
May I use this opportunity to rage about the unit “PSI”? Feel free to ignore.
PSI is a stupid measurement. Sensibly one would use Pascal, hectopascal or Bar (which is 100 kPa).
But even within the us standard or imperial system it makes no sense. Pounds per square inch. Who uses s for square? It’s already taken by second. Square is the unit to the power 2. Pounds isn’t “p” either, it’s lbs aka “libras”. And inch is not “i”, it’s "
So it should be lbs/"² .
Counterpoint: pounds per square inch is eash to visualize because it relates it through units I already know
Countercounterpoint:
I know what a foot is; I know what a pound is.
Make sense of foot-pounds for torque.
Thats super easy X pounds of force on a lever one foot away from whatevera turning
Imagine trying to hold the end of a foot long stick with however much weight hanging off the tip
Allow me to make a hackneyed code block diagram
• <- rotational center | | +👈<<< <- pounds (force applied at radius) ⇡ feet (distance from center)Because the final unit is a combined feet×lbs, it’s subject to the commutative property of multiplication. For example, 89 foot-pounds of torque is equivalent to 89 pounds of force at 1 foot away from the rotational center, or 1 pound of force 89ft away from the rotational center.
I typically imagine it by putting a weight of x pounds at the end of a 1ft wrench held perfectly level, idk.
I understand how it works, but I don’t get it like with other measurements.
Like how I can look at something and say “that’s about 4 feet” or pick something up and say “that’s about 2 pounds”.
I can’t twist the lid on a jar and say “damn! That took 10 foot pounds of torque!” I don’t even know if that’s a lot or normal; I can’t estimate any kind of frame of reference.
I agree with everything you’re ranting about, however:
lbs/"²
Looks like a totally random keyboard mashing and I hate it.
Hence, PSI
This is why you drain your compressor tank daily.
That would have been a dumb way to die…
Absolutely. I told my BIL about it. Good thing he didn’t use it before it leaked and have it pop on him. He’s got kids too and I don’t.
I could see him using it for filling bicycle tires for the kids while they’re standing waiting for it.
Now I’ve got the song in my head.
These small tanks most dangerous failure is zipper style. Water sits in the bottom and rusts in a ring, creating a blowout panel.
I possibly had a close call with the Grim Reaper after patching a garbage truck flat many years ago. Caged, but 110PSI still made me fly across the shop after a damaged band let go, and the air alone peeled the skin off one of my palms. More to that story, but suffice to say that was traumatizing. Now I have a phobia of compressed air and shit like this is why.
Before I could afford a new compressor, I left the garage every time I ran my Grandpa’s old one I had first time after months sitting. Drained after every single use and again check for water after sitting unused a long time. Still get really nervous even just filling a car tire to 32PSI.
If I ever get another one I’m using it outside behind a wall…
Yes! You gotta be careful with these. Glad you made the right decision. My air tank has an expiration date on it for this reason. I don’t use it much, but I plan on pitching it so that I don’t die.
