Every air compressor forms water in the air tank. Compressing air heats it which allows it to hold more water. When the compressed air expands rapidly when it enters the tank which causes the air to cool. When the air cools it can't retain the water and it falls out like rain. Since water is heavier than air it falls to the bottom of the tank where it can be easily drained. All air tanks have a water drain valve. On trucks and busses the operator pulls on a cable that is connected to the drain valve at the end of every shift. This is especially important in the winter where the water can freeze and split the air lines which will prevent the brakes from being released. Trains and some trucks and busses have automatic water drain valves. You can hear them operate because it sounds like a ticking sound every 30 seconds or so. If you have an air compressor shut it off every day and open the drain valve until you hear air coming out of it. The water is mostly harmless but it does form rust which will shorten the life of the tank and is not good for the health of any air tools that are used with that air compressor.
One thing to note. In a home shop. When you are done with the compressor you should just open the drain and let it stay open. This will allow the tank to dry. When you keep air in the tank it is always wet. Most manufacturers say to store the compressor with the tank open.
Would be nice if these air compressor companies would actually do a special coating on the inside of the tanks to prevent them from rusting and just charge some extra money I'd pay it. Otherwise it's instantly a problem from the day of manufacturer leaving the inside get all rusty and crusty.
There is more water in the air than you might think. Air is a mixture of gases, each at it's individual partial pressure. The sum of these partial pressures comes to whatever atmospheric pressure is, about 14.7 psia. Water vapor is the only component gas of air that can be liquified by a typical air compressor. In many areas where prevailing dewpoints are high, the partial pressure of water vapor in the atmosphere can reach 0.4 psia which corresponds to a dewpoint of about 74F. When you compress air from 14.7 psia (0 psig) to 140 psia (125 psig) you increase its absolute pressure by a factor of about 9.5 and decrease its volume by the same factor. This means you increase the water vapor pressure and decrease its volume by that same factor. In the case of 74F dewpoint air, that vapor pressure is increased to 3.8 psia; however it can't stay in gaseous form at that pressure in typical ambient garage conditions. When this air is stored in a tank that is kept at typical ambient temperature, that compressed water vapor is going to condense to liquid water inside the tank until the dewpoint inside the tank is equal to the ambient temperature of the tank. The only solution is to either dry the air with a desiccant or refrigerant air drier (an option too expensive for small shops and homes) or rust proof the tank or fabricate the tank out of some rust proof alloy. In order to prevent condensation inside a 125 psig tank, the intake air would need to have a dewpoint of 12F or less. If, for example, you initially fill a 25 gallon tank with 125 psig air that has an ambient dewpoint of 74F in a garage ambient temperature of say 80F, you are going to deposit almost all the moisture in that air into the tank, in liquid form, as you reduce the charge air volume from 32 cu ft to 3.3 cu ft; btw, this yields about 0.6 ounce of liquid water. It doesn't take many cycles to gather significant water in an air tank if it is not drained. It should also be noted, that inside a compressed air tank, without some sort of air drier, the relative humidity will always be 100%. The internal surfaces of the tank will always be damp. This is the case because the air inside the tank contains water in its gaseous phase in closed-system contact with its liquid phase. These internal conditions inside compressed air tanks without corrosion protection makes them all ticking time bombs. I personally wouldn't keep one more than 10 years or so...
Thanks for the new series to follow !!! It seems that although rusty it is, it's still strong Swedish quality work and good base to work with. Thanks and keep going! Cool looking 1800ES, very rare at least here in Finland.
The Volvo is a fairly solid unibody underneath , with several frame rails and cross members . Sadly these were not sealed well and collected mud and water . But I’m getting there , the rear cross member is almost done, and I recorded a bunch of camera footage , now I just need to edited into a RU-vid :)
@@jaredfox1005 most it requires A LOT of patience. Watch Stephan Goteswinter videos on scraping , he has a two part, that’s mostly what you need . Important to think geometrically. Start with the column, the z-axis, get that flat, use that as a master for the knee. Then get the knee y axis perpendicular to z . You’ll need a good granite square, and a good straightedge . I used a 8” box level, but I got a cheap one that I had to square up myself .
Andy: I know I’m late to this party… the ‘72 unit I have was leaking out of the little silver box on the back of the M41 that holds the reverse switch contact. Not much gasket there.
Yes, this trans had a big leak somewhere around the overdrive unit , or where overdrive bolts to trans . I’m going to disassemble, clean and re-seal it for phase I (just to get the car driving with zippy modern injected B20). Phase II will be B230 turbo .
When air is compressed, excess water precipitates. If it is raining outside, the precipitation is more. In that tank, if the air pump was running regularly, it could buildup a half an inch weekly. I went to work some place in Augusta GA. Nice humid area. And the compressor was having problems. I wasn't the supervisor, but I checked the compressor and found the drain and opened it. I gave up counting after 4 gallons of water and oil muck. But I would venture to say that are 75 gal tank em was at least half full. It took about 40 minutes to drain the tank under full pressure.
Hi Andy, this Is Alberto from ab-shop Italy! I saw your wonderful surface/ tool grinder and It Is what i'm searching around the Europe! ( Because It Is small for small workshop and perfect for a bench) Could you please write me the "brand" or the model that It Is wrote over there? I will search your machine hopefully to find one like that!! Thank you for your help in advance, a big Ciao from Italy, Alberto
Hey, this is a generic Chinese “tool and cutter grinder”, you can find them on Alibaba. Mine is an older one, I bought it used for I think $150. The problem with it is the motor is larger than the standard 6” grinding wheels , so you can’t really use it as a surface grinder . When I get a chance , I want to make an offset spindle , so I’ll mount the wheel to spindle and drive it with a belt to a motor .
@@ab-shop I don’t think Ali express has these , but Ali baba does . I’ve ordered a few things from Alibaba, and they got here fine, a friend ordered a large laser cutter, and he said the shipping experience was very easy .
I've got couple compressors, one is 25 gallon Sears, and the other is 20 gallon Sanborn, when ever I drain them they don't have a lot of water in them, perhaps the humidity locally were the it was use was relatively high, or someone has left their unit on and the unit runs frequently without them knowing it. I'd be suspect of Dewalt Compressors of a certain era after seeing this however.
It's possible to safely test these tanks using a pressure washer...and obviously 60 or 80 gallons of water. If there's a leak or blow-out, the incompressability of water means the pressure drops immediately. You have more risk from the flood water knocking you over than shrapnel.
Don't leave the air in the tank unless you have some sort of dehumidifier that the air goes through before going into the tank. I just empty my air compressor after each time I use it.
My god wellcome to the real world. Akl compressors gave water in them because there is water in the air. Its calles humidity. This is why there is a drain plug at the bottom.
Sounds to me like factory sabotage. Like the half million dollar chiller which came with factory settings which would cause it to self destruct. It had also gone through a drive-by commissioning.
Looks like these companies that make compressors would make the tanks out of a good grade aluminum l know it would cost more but there's no price for safety.
Not a bad idea, however one of the issues with aluminum is it has a finite number of strain cycles , then will loose strength and fail. Steel however has an unlimited number of cycles . That’s why airframes are rated for a certain number of hours .
My 60 gallon CH I bought at Home Depot 21 years ago seems to be fine. But I’m moving in 3 or 4 years and will probably let it go with the house. I want a smaller mobile air compressor. Battery tools have come a long way since I bought the one I have. And I also try to drain it after every use and leave the valve open and the tank unpressurized when not using it.
@HDXFH, the tank was actually made in Wisconsin by a company called MAT enterprises, turns out they make most of the 60 gap compressors sold under tons of brands . Motor and pump were however made in China , but those are fine .
By now most people know that air compressors collect water because there is water in the atmosphere, the compressor collects the air, compresses it in the tank, and concentrates the water. The more humidity, the more water. Tanks can rupture, sometimes with catastrophic results. Drain your tank. Do it often.
This has been a issue with every air compressor I have owned. I'm surprised that you pressured the original owner into refunding your money on a clearly used air compressor.
I can give a some folks a clue that alotta products are being sabotaged at the moment. To have this occur it would take a lot less than just a beer can of salt water and a mild acetate and this would happen. I have heard of the Dewalts and the porter cable compressors in particular. Don't think this ain't a method to steer folks to places like Harbor Freight or online CHinese vendors. It is going on.
The so called Drains are Couplings shoved through a hole and welded on the outside. Tank cannot drain completely. A Half Coupling should be welded Over not Through the hole. They are a bomb and collect a lot of water when in use. A Borescope does not tell you much. Ultrasonic Thickness testing is much better. New Tanks not available.
I would guess that the guy used it hard for a few days, got done with whatever he was doing and never bothered to drain the tank. The belt and pulleys aren't going to tell you a whole lot. Do yourself a favor and order a nice compressor. Box stores rarely carry halfway decent compressors. 80 Gallon, 240V, 5 to 7.5 HP...it will run all the air tools your little heart desires.... and drain the friggin tank after using it. I put an extended drain on mine using soft copper tubing and a ball valve from the hardware store.
When I buy compressors I pay as lot of attention to the ASME pressure certification. MY current one is ASME certified to 480 PSI of working pressure, why does that matter? It tells you the thickness of the metal and the size of the weldments. I working certification of 150PSI usually indicates a very thin tanks which also means it has a short life, especially of the metals used are very low grade.
One of the best ways to prevent this is to pipe straight out of the compressor motor to something like a minivan AC condenser with a repurposed gas cylinder as a water catch tank then route back to your main air storage tank. Bonus is you get nice dry air too.
First thing, when a single stage compressor is set to run well over 100 psi, the amount of moisture the air can "grab" is much higher due to how much it is heated. It is also extremely inefficient due to the air cooling off in the tank which is also how all the moisture drops out. If you need more air, get a bigger tank, a bigger pump, get a two stage pump, or all of the above. Single stage pumps should cut off at 100 psi or less. Second thing, manufacturers are just asking for people to not drain their tanks by placing the petcock in a hard to reach spot. Especially if it gets stuck and you need to use pliers on it. I plumbed mine out towards the side of the tank so it is easy. Edit: comments suggesting lined or stainless tanks are just a band-aid. The root cause is you need to keep your tanks drained! Bare steel is absolutely fine then. It seems there isn't good understanding of how relative humidity works. Compress air, it gets hot, can hold lots of moisture. Air enters tank, cools off, can't hold as much moisture anymore. It's that simple.
You made a smart and safe choice. Everything you said is correct - unless you bore scope them, you have no way of knowing their condition. It can look brand new on the outside but it has cancer (rust) on the inside. Glad the seller was a good guy and he refunded you as well - I would have done the same, but at the same time, I wouldn't sell a bomb to someone 😉
@@jonbutzfiscina1307 nice, those are all great cars . Sadly I only have 1/2 of a two car garage . If I had more room, I’d also have a Saab 96, triumph TR7, Karman Ghia , Chevy Corvair, Datsun 240z and BMW 2002.
in humid conditions.. just one or 2 days of run time wire wheeling or grinding or such where the compressor runs continuously or nearly so will net you a bunch of water... and then since an air tank is well not air tight, or is pumped full of air.. letting it sit for a few months you will get exactly rhat that one had.. which si why big shops run air dryers.. and at home you should drain each day at the end of the day.. my vintage busses that restore and cruise around in.. will spit actual water each time the compressor shuts off.. if its humid out and I put my hand under the air dryer purge valve, a single cycle of the compressor to fill the tanks up will spray my hand till its pretty wet whe nthe dryer purges...
