Fine woodworking says Empty and drain Your Compressor After Every Use

[Andrew Joiner]

I just saw this in the latest FWW . I think it was in the Q+A section in the last few pages. So I need to let all the air and water out of my compressor every day or each time I blow dust off my workbench?



I'll start doing this as soon I finish waxing the bottom of my car.

[glenn bradley]

I imagine its a cautionary statement for those folks who can't remember to do it at a sensible interval based on their use (or periods of non-use).

[Steve Meliza]

IMHO all you really should need to do is bleed off the water, no reason to de-pressurize and waste all that energy unless it's not to be run for a while.

[Neil Brooks]

You probably should, but I never do, and can't imagine I ever will ;)

[Bob Lloyd]

On a job site I typically drain in at the end of a day ,sometimes every other day but that is for the smaller compressors, not a large shop one.

[Rod Sheridan]

You probably should, but I never do, and can't imagine I ever will ;)

That's me, then I added an automatic drain so that everytime the compressor is shut off it drains the water...................Rod.

[Bruce Page]

Andrew, when I bought my IR compressor several years ago I felt that draining the compressor after each use would significantly shorten its life, not to mention being a real pain, so I installed an ADV. The moisture coming out of it is still crystal clear with no signs of rust.
Here’s a thread on it: Finally some air! (http://www.sawmillcreek.org/showthread.php?17659-Finally-some-air%21) There’s a little more info about the ADV further down the thread.
I highly recommend installing an ADV.

[Myk Rian]

So I need to let all the air and water out of my compressor every day or each time I blow dust off my workbench?
Nope. Total overkill.
The only times I had to drain my compressor, was when working on it for whatever reason.
I drain the water when I remember to, or every month or 2, but never let all the air out of it.

[Van Huskey]

I agree, overkill. But do it more in a region of high RH. I just try to remember to do it once in a while, but will if I don't expect to use it for a while even if it has only been a couple of days since I did.

[george wilson]

Draining out the water is sufficient,I THINK. Air compressor tanks are made so thin these days,I'd not like to take chances. I saw a picture of the side of a garage workshop which was blown off by an exploding air compressor tank.

Of course,there could be the argument that compressed air also contains compressed oxygen which could hasten corrosion. And,you never get 100% of the water out of the tank.

[Rich Engelhardt]

Back when I worked as a manager of a 10 min. oil change store, not draining the compressor at the end of the day was grounds for dismissal.
Having said that...I've fallen into a bad habit of not draining my home compressor(s) at the end of the day.

[Bobby O'Neal]

I drain after every day I use it. This is easy because a) it is small and b) I use it once or twice a month. Not a real hassle.

[Will Blick]

like most things, it depends.... if you are in desert climate, you barely collect any water, specially in the winter, I would go 4 months in winter, and can't get a drop...its all about pressure/temp/humidity relationship.... OTOH, if you live in a very humid climate, in warm weather, the air is super saturated with water vapor, compressing it will cause it to condense to liquid in the tank, so draining tank will keep it from rusting. Also, if you have a tall vertical tank, water vapor is much less at top, but when you have small tanks, the water vapor releases out the supply much faster...of course, not a huge issue, unless you are using oil based finishes, nailers, etc. Leave enough water in long enough, tank will rust....rust particles start to exit the compressor. Hence why we are seeing more alum. tanks.

[Larry Edgerton]

I read FFW from when it was black and white until about ten years ago, and then this kind of misinformation became too much the norm. The people that they let write articles became somewhat questionable at times. It became a homeowners mag instead of a pro mag, so I dropped it. Every once in a while I pick one up on a newstand and they have not gotten any better. But there are a lot more homeowners than pros, so good for them. But I don't need it.

It depends on the relitive humidity and dew point, so to make a blanket statement like that shows ignorance. Hard to learn from ignorance.

I have automatic drains on mine here as summers are humid, but in the winter I get nothing for months.

Larry

[Ole Anderson]

Depends on use. Probably no more frequently than once a week, and then only until the water stops flowing. My compressor is wall mounted so I put a 6" vertical nipple with a lever arm ball valve at the bottom drain so water never actually accumulates in the tank. I keep a plastic catch can nearby and just let it evaporate beween drainings. If I am using a lot of air like when sandblasting, I might drain it at the end of the day. It is a 1 hp 25 year old Craftsman with an ASME tank and is still running strong.

[Andrew Joiner]

The recommendation to drain all air and water after each use came from an expert in the compressor business. It must be for liability reasons.

[Clint Olver]

Wow, I guess I'm alone on this. I shut off the compressor and bleed it dry at the end of each day. It's a habit I guess, like shutting off all the lights and locking the door.

[Paul Johnstone]

Wow, I guess I'm alone on this. I shut off the compressor and bleed it dry at the end of each day. It's a habit I guess, like shutting off all the lights and locking the door.

I do it too. It amazes me that people act like draining the compressor is such a burden.
I have to turn it off at the end of the day anyhow. Twisting the drain valve open takes maybe another 15 seconds.
Why not do it every time?

[george wilson]

I have read that 7 years is the safe life of an air tank. But,I know circumstances change that. Things like climate,of course. I bought 2 Junnaire compressors for my wife's jewelry business,and I have taught her to completely drain them every day. I don't want any explosions in her shop,and those compressors are very silent,and VERY expensive.

[Bob Lloyd]

those compressors are very silent,and VERY expensive.

I am not familiar with those, checked them out.:eek:. They are VERY expensive!!!!

[Charles McClain]

One of the smartest ideas I ever, uh borrowed, was adding an elbow, ball valve, cheap coiled air hose and blow gun to the drain bung on my compressor. I just open the ball valve at the bottom of the compressor and walk over to the door with the hose/blowgun and let it rip till I don’t see water coming out. I’ve got a 26 gallon vertical air compressor and the hose is a lot easier than rolling that thing out of the garage to drain it. You don’t really need the ball valve, but it came with the drain kit and I didn’t remove it when I added the hose/blow gun arrangement. It probably takes 20 seconds to drain off the water. I still don’t do it every time it kicks on, most of the time if I just blow off some dust or shooting a couple of brads that’s not even enough to kick it on. If it’s running a lot, that day then yep I drain it.
A little off topic, but probably just as important, I also keep a 3X5 card hanging on the oil drain, with the date of the last oil change, type of oil (manual specifies synthetic) and amount. It keeps me from having to go find the manual when I need to change the oil.

[Dan Carroll]

I read FFW from when it was black and white until about ten years ago, and then this kind of misinformation became too much the norm. The people that they let write articles became somewhat questionable at times. It became a homeowners mag instead of a pro mag, so I dropped it. Every once in a while I pick one up on a newstand and they have not gotten any better. But there are a lot more homeowners than pros, so good for them. But I don't need it.

It depends on the relitive humidity and dew point, so to make a blanket statement like that shows ignorance. Hard to learn from ignorance.

I have automatic drains on mine here as summers are humid, but in the winter I get nothing for months.

Larry

I agree it is hard to learn from ignorance. We are all blessed to have someone like you who shares his wisdom and corrects the missinformation put out by industry, FWW and so many others. I have been in the habit of draining my compressor after each use and I always get water out of it. I will continue to care for my compessor as recommended by its maker.

[Ron Natalie]

Besides my shop is small, if I'd let all the air out of the compressor I'd have no place to put it.
It takes up too much space otherwise.

[William Addison]

I live on the South Texas Gulf Coast which is one of the most humid areas in the nation. I am very remiss in draining my tank and have been for years. About a year ago my small horizontal 2 hp compressor finally died and just out of curiosity I cut it open. It had not been drained in a coupe of years and I expected major corrosion. There was some scale but the tank wasn't corroded at all.

[Neil Brooks]

Besides my shop is small, if I'd let all the air out of the compressor I'd have no place to put it.
It takes up too much space otherwise.

I feel the same way about the sawdust in my machines: if it works, why fix it ? ;)

[Dan Friedrichs]

Emptying all the air (not just the water) probably shortens the life of the compressor, because next time you go to use it, you have to run the pump that much longer to build up all the air you let out. I'm more worried about a pump wearing out than the tank...

[Andrew Joiner]

I live on the South Texas Gulf Coast which is one of the most humid areas in the nation. I am very remiss in draining my tank and have been for years. About a year ago my small horizontal 2 hp compressor finally died and just out of curiosity I cut it open. It had not been drained in a coupe of years and I expected major corrosion. There was some scale but the tank wasn't corroded at all.

Thank you William, That was my gut feeling, but you proved the point.


Emptying all the air (not just the water) probably shortens the life of the compressor, because next time you go to use it, you have to run the pump that much longer to build up all the air you let out. I'm more worried about a pump wearing out than the tank...

I agree Dan. After all, even after draining daily it would not be dry inside.

Next we'll probably have an industry expert tell us to dust off the inside of all our machines daily.

[fRED mCnEILL]

I had a 20 gallon Speedair compressor that I almost NEVER drained. Probably years between draining. And finally it died-after about 35 years. I alway left it plugged in and running.I think I even replaced the electric motor on it. And I live in the Pacific Northwest so it is humid. But finally the tank rusted through.

[Larry Edgerton]

I have five compressors right now, used to have more. The one in the old shop wore out two three phase motors and three two stage pumps, and the tank is still fine. Was drained according to the weather and common sense. Humid, more often. winter, never. It now has an automatic.

Manuals are written just as much by lawyers as they are by engineers, and neither of them are actually trying to make a living with the tools. Reality if you are in business is not the same as reality if you are a homeowner.

Further, my way is green. It takes about 6 minutes for the 100 gallon tank on the 175psi shop tank to fully charge when serviced.

So if I do as is suggested by this lawyer, err, engineer, my compressor will run 1877.14 minutes per year for no reason. Not only costs me money for electricity, but I will get 1877.14 minutes less work out of it per year before it has to be replaced. Now factor in how much of my time and employees time is going to cost me while they sit around waiting for the compressor to come up. So I am losing money and contributing to global warming for what?

Now, thats just one compressor.

The way I look at it I don't drive a Prius, but I do not waste compressed air.;)

But you do as you see fit, it does not matter to me.

Larry

[Curt Harms]

I do it too. It amazes me that people act like draining the compressor is such a burden.
I have to turn it off at the end of the day anyhow. Twisting the drain valve open takes maybe another 15 seconds.
Why not do it every time?

I'm not an expert about either air compressor tanks or pressurized aircraft but I know this. Airplanes that do a lot of relatively short flights have more metal fatigue issues than airplanes that make long flights. One reason is the pressurize/depressurize cycles account for more metal fatigue than the total hours pressurized. Now even cheap air compressor tanks are far thicker than airplane pressure vessels. They also operate at higher pressures, 125-175 PSI for air compressors, 10 or so PSI for aircraft pressure vessels. In common is the inflate/deflate or expand/shrink cycles. Any compressor's tank pressures change with use but a pressurized-all-the-time tank may change 20-30 psi, a fully drained and refilled tank will change 125-175 psi. Are compressor tank lives shortened by these cycles? I don't know but it seems possible.

[glenn bradley]

I do it too. It amazes me that people act like draining the compressor is such a burden.

Some folks won't change a tablesaw blade to get a better cut and that takes all of a minute. Whadda ya gonna do?

[John Coloccia]

I'm not an expert about either air compressor tanks or pressurized aircraft but I know this. Airplanes that do a lot of relatively short flights have more metal fatigue issues than airplanes that make long flights. One reason is the pressurize/depressurize cycles account for more metal fatigue than the total hours pressurized. Now even cheap air compressor tanks are far thicker than airplane pressure vessels. They also operate at higher pressures, 125-175 PSI for air compressors, 10 or so PSI for aircraft pressure vessels. In common is the inflate/deflate or expand/shrink cycles. Any compressor's tank pressures change with use but a pressurized-all-the-time tank may change 20-30 psi, a fully drained and refilled tank will change 125-175 psi. Are compressor tank lives shortened by these cycles? I don't know but it seems possible.

Aircraft fatigue is mainly a problem with aluminum structures. Aluminum is a material that has no fatigue limit, which is a fancy way of saying that ANY stress applied to a piece of aluminum will hasten it's failure. Other metals have a fatigue limit below which the material's life is indefinite.

That's why I kinda of cringed when I heard of aluminum being used as an air tank. It seems like a funny choice to me.

[Neil Brooks]

Some folks won't change a tablesaw blade to get a better cut and that takes all of a minute. Whadda ya gonna do?


I do it too. It amazes me that people act like draining the compressor is such a burden.
I have to turn it off at the end of the day anyhow. Twisting the drain valve open takes maybe another 15 seconds.
Why not do it every time?

What I'm seeing, in the responses, tends to back what I was thinking, on the matter.

It's not a "burden" issue. It's one of cost:benefit.

Doesn't seem like everybody's sold on the benefit, so ... for them/me ... the cost has no upside, and MAY have downside.

That's kind of been my gut feeling, but ... I'm one that virtually never shuts down a PC, either, on the theory that start/stops are the hardest thing on the MTBF (mean time between failures) of the components.

Just a theory, but ... seems others subscribe, too.

[Jason Roehl]

I, too, am not keen on blindly following the manufacturer's recommendations. Call me a skeptic, but a manufacturer has nothing to gain in this quarter for its stockholders from your compressor lasting longer.

[Gordon Eyre]

I haven't done mine for over a year so I just went out and drained it. There was barely enough moisture to show on the concrete. Course I live in a very dry climate. Guess I won't do it for another year or so.

[John Coloccia]

I haven't done mine for over a year so I just went out and drained it. There was barely enough moisture to show on the concrete. Course I live in a very dry climate. Guess I won't do it for another year or so.

When I lived in the high desert of California (Lancaster), my 60gal compressor saw some pretty serious use, and I would drain it maybe every month or two. I hardly ever got any water out. I'm not sure I actually ever even drained the inline moisture trap...it never filled up with anything.

[scott vroom]

I've owned 2 compressors over 13 years. The motor stopped working on my small dbl tank Senco; I replaced with a PC pancake. I use the compressor frequently and have never drained it and I don't have a corossion problem. My compressor holds air overnight so typically it takes little to no time to charge it the next morning. If I drained it every night I'd have to run the motor extensively to recharge it every day: increased motor wear, a higher electric bill, more stress on the environment.

[george wilson]

In the museum,there was a new looking Speedaire in the conservation dept. that was used by the museum weenies. They knew zip about caring for machines. It was NEVER drained,I guess. When the facility was re located,the museum sold off everything in the old location. This guy I know bought that compressor. It had a LARGE tank,over 30 gallon(looked like 55 gallon) tank nearly FULL of water. He got out thick rust flakes the size of silver dollars,I mean LOTS of rust and chunks. All of the water was really loaded with rust sediment.

I suppose those guys would have used their compressor until it started spewing water out!! I don't know how damaged the tank on that poor compressor was,but I'll bet there are a number of THIN spots inside the tank!! It was not a cheap compressor,either.

I think I'm the only one who EVER oiled anything in our own backup shop,or changed the blades. That's the way it was. Everyone else either cared zero for the machines,or had the "I'm not a maintenance man" attitude. I guess I was the maintenance man!

[Rod Sheridan]

[QUOTE=scott vroom;1896373 I replaced with a PC pancake. I use the compressor frequently and have never drained it and I don't have a corossion problem.

My compressor holds air overnight so typically it takes little to no time to charge it the next morning. If I drained it every night I'd have to run the motor extensively to recharge it every day: increased motor wear, a higher electric bill, more stress on the environment.[/QUOTE]

Scott how do you know you don't have a corrosion problem?

As for draining it, it only takes a few seconds to allow the water to be discharged, no need to blow down down the tank...........Rod







As for the

[Andrew Joiner]

In the museum,there was a new looking Speedaire in the conservation dept. that was used by the museum weenies. They knew zip about caring for machines. It was NEVER drained,I guess. When the facility was re located,the museum sold off everything in the old location. This guy I know bought that compressor. It had a LARGE tank,over 30 gallon(looked like 55 gallon) tank nearly FULL of water. He got out thick rust flakes the size of silver dollars,I mean LOTS of rust and chunks. All of the water was really loaded with rust sediment.




Thanks George,
I like real life examples when we discuss these things. That would be a good reason to drain once in a while. After all they paid for a 30 gallon tank, might as well fill the full 30 gallon space with air!

My own experience is pretty boring. I bought a well used 20 gallon compressor years ago and drained it after 10 years. I was in a humid climate and had no idea if I was the first to drain it. I got a cup or 2 of water and goo out of the drain. It ran fine for the 15 years I owned it.

Now as hobbyist I have a cheap pancake compressor. It's 10 years old and I drain it 3 or 4 times a year. I get a tablespoon of water out at the most.

I've been reading more magazine tips, so I'm off to wax the inside of my hubcaps and polish all my tool cords with Armor-all.

[Neil Brooks]

I've been reading more magazine tips, so I'm off to wax the inside of my hubcaps and polish all my tool cords with Armor-all.

You're going to be amazed at the difference these things make.

Similarly, with spring upon us, I have to go change out the air in my car and bike tires.

See ya' :)

[scott vroom]

I just checked my PC 6 gal pancake compressor....not a single drop of moisture; I've NEVER checked it and I use it frequently. Based on my quasi-scientific experiment, I'd say the FWW author is way over the top on his recommendation. At a mimimum, he should have qualified his recommendation. I let my subscription to FWW expire a couple of years ago after I realized I was not their target audience.

[scott vroom]

Rod, you bring up a good point....I couldn't know for sure whether there's corrosion unless 1) the compressor fails, or 2) I cut the tank open to view it's condition. However, I posted more recently that I had just opened the valve and got zero moisture - and this was after weeks of daily use without draining. I'm in the SF Bay Area where humidity is moderate year round. I think the blanket warning by the FWW author should have been qualified by a discussion of how ambient humidity affects moisture acccumulation.

[Thomas Canfield]

I just checked my PC 6 gal pancake compressor....not a single drop of moisture; I've NEVER checked it and I use it frequently. Based on my quasi-scientific experiment, I'd say the FWW author is way over the top on his recommendation. At a mimimum, he should have qualified his recommendation. I let my subscription to FWW expire a couple of years ago after I realized I was not their target audience.

Scott - If you just open up the drain valve on a pancake tank, then you could have almost an inch of water in the tank below the drain valve. On a pancake tank, you have to tip the tank/compressor to get the drain at the bottom. My little Porter Cable pancake will make water, and I have added a tilt base and elbow to drain the tank. That is what I consider a design flaw to the pancake tanks.

[Don Morris]

I've had my 2hp compressor 30+ yrs. It's been serviced once when I came back from a 4yr overseas deployment. Other than that I oil it when the oil is low. Works fine.

[phil harold]

if there is moisture water in there when you drain the compressor the air will frost up the drain and water will not flow out
letting it stay open and melt / drain will solve that problem
on portable compressors some times it is necessary to till the tank to get all the moisture out