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 😎
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.
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 all 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.
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?
The condensate is still way over 100 degrees due to pressure. If it reaches the top of the pipe it can create a shock wave (think water hammer) that will travel to the next corner and blowout. The condensate then turns back to steam at atmospheric pressure.
You’re really overestimating the force of a home compressor. I’ve seen 2500PSI tanks rupture. Those will kill you
That would have been a dumb way to die…
Now I’ve got the song in my head.
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.
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.
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.
This is why you drain your compressor tank daily.
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
I agree with everything you’re ranting about, however:
lbs/"²
Looks like a totally random keyboard mashing and I hate it.
Hence, PSI
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…
