I used to drain mine but it was a hassle and I’ve found the tanks last longer than the compressor. So I just have a water trap to keep the lines clean.
I’ve wondered if frequent draining of the tank really does much. A little water always comes out of my old Craftsman. But, it seems to me there’s always some water in there, right?
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That’s an air tank that had a leaking drain petcock, so the brilliant owner decided to remove the petcock and replace it with a plug. It was then used for a number of years without ever draining it, because it couldn’t be drained. The bottom of the tank rusted from being wet all the time, and post-rupture analysis revealed it had eroded to a .070 inch thickness. The owner who messed it up eventually decided to sell it, and the guy who bought it brought it home and began pressurizing. When it got to 100psi, it ruptured and flew across his garage. Fortunately, no one was hurt, though I imagine the new owner had to change his pants.
That’s one of several good object lessons in why you don’t want to let water sit in your tank. Sure, you’ll probably get away with it most times, but then NASA got away with severe shuttle defects through many launches… Until they didn’t.
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I’ll eat my words if need be but I find it hard to believe that 100# could blow a tank apart that bad. The other day I popped the release valve at 120# and outside of a pretty good stream of air, not much there there. Also if a tank is rusting, wouldn’t it tend to form a rust hole so it wouldn’t hold air rather than rusting the whole tank to the point of catastrophic failure?
I’m just asking I guess. If this is a safety issue.
Usually, yes, that’s how it happens, and you hear the hissing and know you need a new tank. But there’s always that rare instance when the norm doesn’t happen, and when you’re dealing with compressed air that can get dangerous.
As to 100psi not being much, keep in mind that that’s only 10-20psi less than a semi tire, and we’ve all heard the stories about what happens when one of those things blows:
When you pop the release valve you’re controlling the pressure release, and letting all that energy out slowly. It’d be very different if the entire tank dumped out of that valve instantly - it’d peel the skin right off your hand, or worse.
It’s kind of like the difference between stopping from 150mph gradually using your brakes, or very quickly using a wall. Same initial speed, same ending speed, very different outcomes for your health.
It sounds like maybe that compressor sat unused and unpressurized for a while, rusting all the time. Then when pressurized the thin remaining metal let go. Makes sense to me.
That’s why most all pressure testing is done with water. If it lets go, everything just gets wet, things don’t fly across the room.
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Craftsman hand tools have been made by Stanly for years. Their power tools have been made by many different manufacturers over the years. Stanly bought the Craftsman name…not sure who will make their power tools now. But then again I think SearsMart won’t be around next decade.
Most all oil-less compressors are direct drive, the compressor runs at motor speed, and that’s why they are so noisy. Also, the horsepower ratings of home compressor motors are inflated to the point of ridiculousness. The full load amp draw on the motor is a better indicator of the motor’s power. In order to deliver a true 3.5 horsepower to the compressor, a motor would have to draw around 25 amps on a 120 volt AC line. Most household 120 volt outlets are good only for around 15 amps although you can get them rated up to 20 amps.
Trust me, that commercial air compressor powered by a 5 horse 3-phase motor in commercial shop will put out way more air than a home compressor labeled as a “6.5 peak horsepower” unit. That’s because when the national electrical apparatus association (NEMA) says “5 horsepower”, they mean the motor can deliver 5 HP continuously, without overheating. Not a flash reading in a highly overloaded state.
Sears is selling off their well known house brands like Craftsman and Kenmore. Once that it is much easier for them to shutter the stores and go on line exclusively if they want to and the public will go for it. I’m old school. I still like to touch stuff before I buy it. Especially stuff that touches back, like furniture and bedding.
The 40 gallon tank 3 phase compressor at the shop needed the motor repaired once and later replaced in 20+ years of service and I sold it for several hundred dollars to a competitor who wanted it for a backup. It had an upright tank with the petcock at bottom center which resulted in it blowing virtually dry each night when shut off. The original 2 stage compressor was still working without complaint the last day I used it. Having 3 phase power available can be a great benefit when shopping for a compressor and other equipment.
Interesting. I wouldn’t have guessed it possible to eliminate 100% of the compressor oil using in-line filtering. Here’s one source that claims paint contamination is a reason some automobile shops use oilless.
“The following applications illustrate why the automotive industry relies on oil-free air throughout the car manufacturing process, from assembly to the application of a high quality finish… Water-Based Paint – Water-based paints are increasingly used in paint baths and spray painting but are very sensitive to silicones, which are found in compressor lubricating oil.”
Perhaps it is more of an issue with water based paints?
I’d say that is a pretty good thought!
Silicones are generally bad for any paint but solvent based may be able to accept very small amounts of oil vapor. Water based paints may run afoul of that old oil-and-water separation problem. Water separators have always been used to keep water off of solvent based paints for similar reasons.
As a side note, I’ve shot water based primer on a project car with my oil compressor, water separator, and filter ball at the spray gun successfully. No fisheyes or spots.
Reciprocating compressors are being replaced with scroll and screw compressors in industrial use.
Makes sense. Fewer parts, quieter, higher reliability and more energy efficient. My pool heat pump has a scroll compressor. It’s about 12 years old now and has lived up to the claims. First year I ran it all the way to halloween in northeast and only cost about $90 for that month with temps in 40s at night…
Sorry but looks like spam to me. Isn’t that the Harbor Freight brand?
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I agree and yes, I believe it is.
Yes that is a HF brand, it was one I was considering when I started this thread.
when I was searching for a compressor I found several that appeared to be the same but being sold under various house brands.
But as noted I went with a smaller national brand unit.
Lets see, Abu joined 8 hours ago and posts a link.
Someone who calls their self Olivia joins 8 hours ago and ‘likes’ the link post.
Sure looks like SPAM to me.
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It’s spam. They are actually paid to do this. Too stupid or too lazy to get real jobs. So they get these sleaze jobs and go around to different forums and post this crap.
Does Harbor Freight pay for this crap?