Tool Talk
Woodworking Forum => Woodworking Forum => Topic started by: JessEm on April 11, 2012, 07:57:41 PM
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I picked-up this old air compressor on a whim while browsing craigslist. The guy wanted to trade for a small, portable compressor and I had just the ticket. He spoke very highly of this old compressor on the phone and said all the right things; mainly that it works great, is quiet and drained clear. Well, I bit, and now I'm having a concern. I was all caught up in the moment of a great trade and the serious-ness and DANGER of using a bad tank had escaped me.
The tank is rated for 200 psi working pressure and is currently set to stop filling around 115. I've brought it up to 115 numerous times in the few days I've owned it, and it does work great... BUT... Something tells me I'm playing with fire if I don't get this tank checked out...
I've tapped on it with a ball peen hammer (while empty) in various places and the sound does seem consistent. By no means a true test, I know... Anyone have any ides? I've heard of hooking up a pressure washer and bringing it up to 150% of its rating, but would that ruin my pump? Is there some kind of ultrasonic wall-thickness test that won't break the bank?
Also, each half of this tank has a 2-5/8" hex-shaped access cap. What is this for? My thought is for clean-out, but it already has a drain on the bottom... Maybe a BETTER clean-out? My other thought is that it's for hooking-up a bigger tank?
(http://i10.photobucket.com/albums/a131/JAEMERSON_/002-44.jpg)
(http://i10.photobucket.com/albums/a131/JAEMERSON_/001-54.jpg)
(http://i10.photobucket.com/albums/a131/JAEMERSON_/008-34.jpg)
(http://i10.photobucket.com/albums/a131/JAEMERSON_/003-46.jpg)
(http://i10.photobucket.com/albums/a131/JAEMERSON_/009-26.jpg)
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Well, at least it has a certification tag on it, even if it is 80 years overdue for recertification ;P
The rust is on the inside, not the outside, so looking at it doesn't tell you anything. The plugs are for inspection, but good luck getting them out after all this time.
Do NOT try to pressure test it using a pressure washer, that is a good way to destroy a nearby building.
There are folks who can test it properly , and it doesn't cost all that much, the general theory is to fill it ***entirely*** with water so there is no air to be compressed that can explode if suddenly released by the tank failing. The pressure has to be accurate, and reasonable, you aren't testing it to 1500 pounds!, probably just to 300, you just want to test the tank, not destroy it -P
Personally, I would not use a tank from 1938, even if it tests ok,metal fatigue is a concern for stuff made before the 50's....
2c
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PS: In case you didn't know, .140 is the thickness of the tank and end caps when it was new, 10 ga sheet metal ;P
How thick is it now? ......
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rusty, I'm going to have to borrow your WD40 and get those caps off and look inside. ;)
*I think* the area most vulnerable to rust would be along the bottom, where the water collects... I have no idea how to check the thickness of that.
If the thickness of an OLD tank was .140, I wonder what the thickness of a NEW tank from LOWZ is... Hmmm. I have my suspicion, but I could be wrong... :)
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>*I think* the area most vulnerable to rust would be along the bottom, where the water collects...
Generally, yes, because rust/sludge trap the water there when you drain down the tank and keep it wet.
But another thing to look for is carbon or oil, when compressors get old and tired, they leak oil past the rings, the oil goes into the tank. Compressor oil has a high flash point, but motor oil doesn't, and you don't know the history of the machine, if some klutz was putting motor oil it , it can create a flash/explosion hazard also. (Old machines are fun, but they can be a little scary too , A millwright I know told me he saw an IR compressor blow the head off and send it through a wall for no apparent reason whatsoever....so check out the compressor also )
The plugs aren't coming out, trust me ;P
OK, since you probably are as stubborn as I am, Ponder: the tank has been expanding and contracting lengthwise as it fills up and empties out , for the last 70 years, the plugs are not round any more...
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>*I think* the area most vulnerable to rust would be along the bottom, where the water collects...
Generally, yes, because rust/sludge trap the water there when you drain down the tank and keep it wet.
But another thing to look for is carbon or oil, when compressors get old and tired, they leak oil past the rings, the oil goes into the tank. Compressor oil has a high flash point, but motor oil doesn't, and you don't know the history of the machine, if some klutz was putting motor oil it , it can create a flash/explosion hazard also. (Old machines are fun, but they can be a little scary too , A millwright I know told me he saw an IR compressor blow the head off and send it through a wall for no apparent reason whatsoever....so check out the compressor also )
The plugs aren't coming out, trust me ;P
OK, since you probably are as stubborn as I am, Ponder: the tank has been expanding and contracting lengthwise as it fills up and empties out , for the last 70 years, the plugs are not round any more...
Yes, I'm stubborn. And that sounds like a challenge. ... I'll let you know how I fare, and what I find...
The oil in the pump does appear to be motor oil. ... That was actually another question I had... Whatever it is, it's keeping this pump working good because 2 people can stand over it while it's running and have a normal conversation... I guess I'll have to check inside the tank for oil leakage too, WHEN I get those caps off... ;)
Thanks for all the input so far, BTW.
Jesse
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Rusty's fibbing!
Those inspection ports will pop right out, of course if the tank is in sorry shape it just might become free form sculpture in the process. Given the date of manufacture I'll bet the inspec ports were doped with Litharge & glycerin when they were installed.
Method A- hydraulic wrench - you probably don't own one.
Method B- slugging wrench & sledge - heating the boss helps with this method.
Method C- drill a large hole through the center of the plug. Insert sawzall in hole and cut nearly to the threads in 6 directions. Grab a decent sized punch or cold chisel and collapse the sections into the hole you drilled. A Parker 401 air hammer works best.
Shouldn't take more than 20 minutes if you use an air hammer.
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I have heard stories of tanks exploding and such but when my air compressor tank let loose it was just a small pop and a rush of air as just the weak spot on the bottom of the tank that rusted through from the inside let loose. Nothing to hurt anyone just a little surprise and some mess to cleanup after the tank puked all over the cellar floor. Maybe I was just lucky. That was when I learned about draining the water out of a tank. :)
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Well, I have some good news, and some potentially bad news. First the good...
BAM!
(http://i10.photobucket.com/albums/a131/JAEMERSON_/014-1.jpg)
Never underestimate the power of a 24" pipe wrench :) Probably the best $3 I spent last summer.
(http://i10.photobucket.com/albums/a131/JAEMERSON_/012-1.jpg)
Now the potentially bad...
I did some probing around with a bore light and extension magnet and this is what I got... The paper is 8.5x11.
(http://i10.photobucket.com/albums/a131/JAEMERSON_/013-3.jpg)
Well, those chunks are scary but I'm holding out hope for this. They look big but I think the are immensely enlarged due to two factors; the natural property of rust and oxidation, and the fact that they are completely infused with oil.
At this point I'm going to look into tank certification and see what it will cost to have this tested (because I have no idea). If it's under $100 I'm in. At this point it's educational. Maybe someone will read this thread and learn to steer clear of old tanks. Or maybe we'll be surprised and they will learn not to write them off. I'm thinking it's probably the former, and that I will be throwing good money after bad, but you never know...
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I have heard stories of tanks exploding and such but when my air compressor tank let loose it was just a small pop and a rush of air as just the weak spot on the bottom of the tank that rusted through from the inside let loose. Nothing to hurt anyone just a little surprise and some mess to cleanup after the tank puked all over the cellar floor. Maybe I was just lucky. That was when I learned about draining the water out of a tank. :)
Thanks, Lewill2. I've heard stories similar to yours. I've also heard it can be equivalent to a couple sticks of dynamite. So I'm not sure what to think. ... I suppose they're both possible, depending on different factors...
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Since you've heard stories, how about some pictures?
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>can be equivalent to a couple sticks of dynamite
Remember, diesel engines work by causing oil to explode...tiny quantities of oil...
> I'm going to look into tank certification
It already failed, it has oil impregnated rust.
You need to get all that oil out of there first.
Then you can hydrostat the tank....
PS: That oil came from somewhere....need to address that also..
PPS: I *am* impressed you got the plugs out :)
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Aunt Phil, that's heinous... But I'm not sure what, exactly, we're looking at? Did the shut-off valve go bad so it just kept filling until... Or is this what happens when you try filling a compressor tank with argon (ala 2000+ PSI)?
As messy as it is around there, I'm not surprised SOMETHING went wrong... ;)
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fire extinguisher guys have testing tanks, so do some oxy acet places.
Skip
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Aunt Phil, that's heinous... But I'm not sure what, exactly, we're looking at? Did the shut-off valve go bad so it just kept filling until... Or is this what happens when you try filling a compressor tank with argon (ala 2000+ PSI)?
As messy as it is around there, I'm not surprised SOMETHING went wrong... ;)
Those pics are of a formerly neat garage after a free compressor with a slight leak in the tank ruptured. According to the owner of the free compressor he was watching the machine build pressure, and it was around 120psi when it let go.
There is one hell of a lot of stored energy in an air receiver and it should be respected. Unfortunately I've seen a number of people who know that completely fail to respect the potential disaster.
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Thanks, Aunt Phil. And don't take me the wrong way (I don't think you did), I just like to question things... ;)
As for this tank, I will definitely be respecting it and not use it unless I get it tested. It's sad, to think it could possibly be tossed when it still has plenty to give, but it's not worth chancing.
On a side note, I noticed a lot of the newer compressors at the Depot and such are rated 150-175 psi. I think that answers my question about wall thickness of old vs. new. The old ones were rated higher... I think they were also intended to last much longer, hence the clean outs. Theoretically, they could last forever if properly cared for (IE. periodically coated on the inside with rust inhibitor, etc.)... New ones basically say they're disposable in the manual, and should be thrown out after "X" years. They don't make 'em like they used to!
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This is really odd, I have found a tooltalk member before and now you that live in the relitivily same area. I am guessing at least because I saw the add on craigslist the other day.
I think that tank should be tested, at least I wont be near it untill its tested.
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I could do a book on the JUNK called compressors today, but I won't bother. If you look at every one of the ruptures in the pics you'll notice they all appear to have begun at the bottom of the receiver and rolled on. You also notice there is near no predictability on the path the rupture will take.
Even current production ASME labeled tanks (my hunch is most of the ASME stamps are fake) are garbage. If they to code, they only are for a short time after manufacture because every one is manufactured to minimum necessary to get the ticket. A lot are also made from crap steel that never gets tested.
Testing a tank is a simple job that can be done in a cattle troth. I'll be damned if I explain it though because some fool will try it his way and kill somebody. I won't even be in the same room while bottles are being hydroed because the clown actually doing the testing have no idea of the physics and little knowledge of what they're doing. Strong backs count for more than smarts in that field of endeavor.
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The carry around air tank/ air bubbles for filling tires, at work that have been boughten recently all have the words: Destroy by XXXX, about 4-5 year life span on the tanks. I use a steel tank at home for filling tires that was new in 1975, never have gotten water out of it.
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>The carry around air tank/ air bubbles ...
Should I even start on the morons that try to convert propane tanks?
Those little carry tanks scare the jeepers outta me, they are made of the thinnest metal that will just barely hold together at the minimul pressure you can rate a tank for to fill a tire.....
>Destroy by XXXX, about 4-5 year life span
Because someone is finally willing to admit that there is a finite lifetime on them...
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A little bit off-topic, but when I was a kid they showed us a scuba tank that ruptured while filling. It was pretty much turned inside-out and they said it killed everything big enough to die in the immediate area.
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two ways to help you install a blowout valve in the tank ( 75 lbs)
MAKE FRIEND S WITH AN OIL BURNER SERVICMAN THEY HAVE WAYS OF CHECKING THE THICKNESS IF A TANK BY USEING A PROBE FROM THE TOP WITH OR WITHOUT FLUID IN IT
I BELIEVE IT IS SONAR (NOT SURE) bob w.
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>The carry around air tank/ air bubbles ...
Should I even start on the morons that try to convert propane tanks?
OH PLEASE do tell why converting a propane tank that is made to test to 800psi is moronic. I really want to know this information.
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Because bad things happen if you don't let all the propane out first...:P
(And I am talking about the stamped sheet metal ones, not the bigger tanks)
As a general rule, converting a tank that had fuel in it into a tank to hold compressed air requires a certain amount of common sense, something the average joe seems to occasionally lack....
How come after all these years we are still building compressors with air recievers anyhow? Ahh..yes...price...
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Because bad things happen if you don't let all the propane out first...:P
(And I am talking about the stamped sheet metal ones, not the bigger tanks)
As a general rule, converting a tank that had fuel in it into a tank to hold compressed air requires a certain amount of common sense, something the average joe seems to occasionally lack....
How come after all these years we are still building compressors with air recievers anyhow? Ahh..yes...price...
Are you referring to the 1# propane cans Rusty? Why in hell would anyone want a receiver that size? Granted some machinery is built with that size buffering tank internal to the machine, but as a receiver I'd call a 1# tank useless.
Receivers are buffering devices in many cases, rotary compressors rarely use large receivers because the piping system beyond provides sufficient storage. In screw systems the receiver acts as a secondary oil separator. In low grade homeowner compressors the receiver becomes a sales tool. How many posts can you find where the size of the receiver is in the first 2 lines but the poster is clueless on cfm available"
Once more Rusty, kindly enlighten me, EXACTLY what can happen if and when Herbie Homeowner fails to completely evacuate a propane cylinder of propane prior to pumping air into the bottle?
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Near where I worked some poor schmuck leveled his garage. The fire chief told me he was trying to fill a 20lb propane bottle with compressed air...
I dunno if he was trying to use it with a compressor, or as a tire-caddy, if it partly full, rusted out, or if he accidently filled the wrong one, but it made a very big mess...
Mostly tho, the issue is going to be that the tanks that are easily available are not the ones still in good shape, because you can take them back and get more propane, but the tanks that the propane guy won't refill anymore because they are so scary looking he doesn't even want to stand near them. These things sit on the wet ground, in all the caustic grud from the gas grill, and the bottom rots to heck. The only saving grace is it rots on the outside..
>the receiver becomes a sales tool.
Sadly, yes...
And a little bit of "we have always done it that way"
We have flash water heaters, we should have flash air compressors....
Triplex, variable speed drive.....
Probably can't make them in china for $25 tho....
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Because bad things happen if you don't let all the propane out first...:P
(And I am talking about the stamped sheet metal ones, not the bigger tanks)
As a general rule, converting a tank that had fuel in it into a tank to hold compressed air requires a certain amount of common sense, something the average joe seems to occasionally lack....
How come after all these years we are still building compressors with air recievers anyhow? Ahh..yes...price...
Are you referring to the 1# propane cans Rusty? Why in hell would anyone want a receiver that size? Granted some machinery is built with that size buffering tank internal to the machine, but as a receiver I'd call a 1# tank useless.
Receivers are buffering devices in many cases, rotary compressors rarely use large receivers because the piping system beyond provides sufficient storage. In screw systems the receiver acts as a secondary oil separator. In low grade homeowner compressors the receiver becomes a sales tool. How many posts can you find where the size of the receiver is in the first 2 lines but the poster is clueless on cfm available"
Once more Rusty, kindly enlighten me, EXACTLY what can happen if and when Herbie Homeowner fails to completely evacuate a propane cylinder of propane prior to pumping air into the bottle?
With your superior knowledge of physics already proclaimed, you should simply answer these questions for yourself. Unless of course, your intent is just to put someone on the spot; in which case you may have a weak seam or two yer own self, perfessor :) Just sayin'
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Sadly the internet has become the In Turd Net of misinformation based on pathetic public education.
Compressed air along with most compressed gas is well settled science, although brilliance continues to flow from such oracles as the Fire Chief from 2 districts down the road, DumDum the paint salesman and a hundred others.
The likelyhood of correct let alone sane information flowing has been pretty damn minimized.
Just as there are 1000 fools posting that the Franzinator can't work, there are 10,000 posting amplified stupidity.
Why bother pointing out the odds against Diesel effect occurring in a cylinder that contains a small quantity of Refrigerant 290. It happens according to some Dullard Fire Chief. Hell, just read the NY City Fire Code, largely written to sell permits and issue citations. Never mind approaching the legitimate hazard to firemen inside a burning building, that doesn't generate revenue.
Society in the US is drifting all too rapidly toward that of a pathetic small island floating North of France. It's just a matter of time till cops here run around confiscating every compressed gas cylinder in site. After all dimwits and dullards must be protected. Kids won't learn Drano + aluminum foil in a bottle produces blast.
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>Sadly the internet has become the In Turd Net of misinformation
Has become? ROFL, the internet has been a cesspool of worthless blabber since about a week after it became accessible to the general public.
> brilliance continues to flow from such oracles as the Fire Chief
I met too many "Fire Chiefs" while doing environmental work to argue that point...
>Diesel effect..
No, but draining out the remaining propane while closed in your garage is always interesting...
>a pathetic small island floating North of France
Now,now, just because the Brits invented liquid air ;P
> After all dimwits and dullards must be protected
There is a dstinction between taking away all the fun toys, and telling them that there are possibly some hazards that they should be aware of....
> Drano + aluminum foil
Alumnium foil is really dangerous and should be banned ;P
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Thanks for the input. Between the debate, I've learned a few things in this thread.
I haven't had any luck finding someone to test this tank yet (but I' haven't given up). I want to have it tested, out of curiosity as much as anything at this point. I have also started looking at replacement tanks. I was shocked and amazed that search terms like "air compressor tank" and "air compressor tank only" turned up virtually ZILCH for tanks... However, I hit the jackpot with "air receiver tank." Never would've thought to try that... Can't say I've ever heard someone call a compressor tank an air receiver.
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If you do find an easy quick check, I would love to hear it
Just yesterday I saw an old Binks brand receiver at the town dump! Its maybe 50-60 gallons and heavy!! Big substantial feet on it, no cheapie once. No visible rust at all. 90% still painted in fact.
Looks like the old compressor pump was leaking for years. Gobs of old spilled oil all over it. Pump is gone along with the motor which was probably salvaged.
I gave it a shake and heard no water inside?
But its big and its messy and no sense lugging home a bomb.
I could use it though. I have a spare 5hp and a couple of junk pumps I could press into service until something better came along.
My basement compressor is a cheap little 1960's Sears thing, and due to blow up about 2 decades ago. I only use it for nailing and blowing off things and the occasional airbrush adventure.
The pump was dead when I met it (yard sale 20 bucks). Stuck reed valves and shot rings.
I cleaned up the valves easy enough, but couldn't get rings. You would think some chainsaw or lawn mower rings would fit?? But I couldn't find them.
So I slipped the rings off and lined the piston slots with thin (00something) brass shim stock, put them back. Its been going like this for 10 years now. It uses a little oil, but not bad. I don't run it that much.
But the tank was weak and measly looking when I met it, and I expect it hasn't improved much over the years.
yours Scott
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This thread was covered awhile back on another board. With photos of the scuba shop that the cylinder exploded, old gas station compressor that went through a concrete block wall, and the best, an ordinary 55 gallon steel drum, buried in concrete under a corncrib floor and used for 40 years as an *air reciever*, until it blew and lifted the concrete up 4 inches. I have a compressor and tank I bought from a gas station, when cleaning off the oil found a great little brass tag that told me it was built in 1948. Right now am using a little 20 gallon upright tank tagged, (Service Station Equipment Co.), 1938. Have a little AC compressor on top, fill a tire once in awhile, safety valve pops off at 80psi. Only run it when I need it. But thinking may be its time to retire these tanks.
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I suppose if you want to know how hydros are done this is as good a place as any on the WWW.
http://www.hydro-test.com/files/393-101.pdf
Of course it might be a bit dollar intensive to set up in your garage.
It can be done the same way it was in 1960 when the whole extinguisher business went hydro happy.