DIY Air Compressor Made From Refrigerator And Fire Extinguisher

[Giorgos] wanted to build a pneumatic solder paste application tool but needed an air compressor to power it. Instead of going out and buying a compressor, he decided to build one himself. It sure is an ugly duckling but we’re impressed with it’s performance.

The air tank is an old spent fire extinguisher. The stock valve was removed and the insides were cleaned out. Out of curiosity, [Giorgos] figured out the volume by filling the tank with water, then measuring how much water came out. It turned out to be 2.8 liters. Two holes were drilled and threaded bungs were welded on to attach inlet and outlet lines.

The compressor portion is straight out of a refrigerator. Besides the compressor being free, the other benefit is that it is super quiet! Check the video after the break, you’ll be astonished. [Giorgos] did some calculations and figured out that his solder paste applicator needed about 8 bar (116 psi) of pressure. The refrigerator compressor easily handles that, filling the tank in 1 minute, 25 seconds.

On the output side of the tank resides a pressure switch for automatically filling the tank and a regulator for ensuring the solder paste applicator gets the required pressure. This isn’t the first time we’ve seen a refrigerator compressor used as an air compressor. Check out this dual setup capable of 400 psi.

58 thoughts on “DIY Air Compressor Made From Refrigerator And Fire Extinguisher

  1. Using a fire extinguisher as an air tank this way is very specifically Not Recommended for valid safety reasons. It’s bad even if it’s relatively new, because fire extinguishers are not meant to be filled with air that can contain water and they can corrode quickly when not in normal service. Same thing for Freon cans, which is why they’re made with valves that prevent them from being filled once empty.

    Air pressure tanks are not a good thing to fool around with. They store energy, lots of it, and if they release it all at once can seriously maim or kill you. Using the refrigerator compressor is OK (it will eventually seize if not occasionally fed oil, and I don’t want to know where the Freon from the refrigerator went) but you do not want to screw around with hacked gas pressure vessels.

    1. Ohhh.. You’re no fun. Let him kill himself. He could add a dryer stage between the compressor and tank. Most air compressor tanks are made of steel and will rust through if not taken care of. That’s why they have a drain valve on the bottom, correct? How much rusty water comes out of your air compressor when you drain it?

          1. It probably has the relief valve, but it’s not connected in this setup :-) that would need check valve and second line going to pressure switch. Also you would hear the PFFFFT sound when it switches off. This is not the case. Also he has no drain valve at the bottom, he has only safety valve on top.

      1. localroger may not be any fun, but he is right… and it’s not just a question of the material, carbon steel, as you point out, is commonly used in this service, but its also a matter of corrosion allowance and even prevention. I’ve regularly specified clad or coated internals for clients that wanted a carbon steel pressure vessel in corrosive service. My preference is for something that will last forever, theirs is something that will be cheap and last for only as long as it needs to… their preference is the only one that matters, HA!

      2. My grandfather built a air compressor similar to this back in the 70’s it sat outside in Seattle Wa, a very damp place, and it worked fine and never failed right up to his death this year. He used a compressor from a car AC system and a small AC motor mounted with 2 Freon tanks for volume. He got the instructions out of a garden magazine if I recall.

        Out of curiosity if one is worried about rusting tanks cant you fill the tank with paint or epoxy and drain it to give it a good coat and block the moisture from reacting with most of the tank? I am sure the burst disk and other safeties might be effected but over all wouldn’t that limit corrosion?

    2. This. Very much this. I’ve seen it most often with propane BBQ grill tanks. As localroger said, the tanks are not designed for moist air. The failure mode is the scary part: They rust from the inside out, so you have no idea the thing is going to fail until it blows shrapnel around your shop.

      1. when an air compressor tank rusts out and fails, there is no explosion. It will start as a pin hole and the air will gradually leak out. I’ve seen that more than once. I’ve never seen one turn into a bomb from rusting out.

        1. Kaine, do a google search for “air receiver rust explosion” and then you’ll have seen several that turned into bombs – there’s even a couple of videos out there for you to enjoy!

        2. I’m glad you’re lucky enough there to have never seen it. Neighbors tank blew- no one was home; they noticed all the knick-nacks and shelves on the wall were on the ground. Figured it was the cat.

          Went out to the garage a bit later and found the compressor wrecked, the wall shredded, and debris all over the garage.

          Had someone been there it would have been a ‘bad thing’.

  2. It is a bad idea to use an extinguisher as a tank in this case . The pressure is going up an down so the stress is going up and down , the weldings and the steel of the tank are designed for constant pressure. Some fatigue cracks can develop and an explosion of the tank can happen. This priocess can be accelerated by corosion : there is not drain of condensation in the tank . Reference Ashby boks

    1. In France by law all the vessels under pressure have to be tested and by approved by the Inspector of vessel under pressure . Tanks for extinguishers are not approved as tank for air compressor , it is written on the extinguisher.
      The steel of such an air compressor tank must have a high A% ( deformation before break :a low Re elastic limit and a high R break limit .) So you have to use steel with a carbon % low for this kind of tank , the welding will not affect A% . Each cycle full / empty develop microscopic cracks When a crack appears this crack is growing slowly and the tank leaks when the crack is big enough With other steels when the crack grows to the critical size the crack propagation speed increase very fast and the tank explode . This kind of problem happened in Comet plane, steam engine boilers and so on .
      http://www.elsevier.com/books/materials-selection-in-mechanical-design/ashby/978-1-85617-663-7

      1. The yield strength of carbon steel is far high than aluminum. If the pressure vessel were made of aluminum, as in airplanes like the comet, then stress fracture would be an issue. The pressures he running make the risk no higher than on a commercial air compressor tank.

    1. The best of these use a piston-type vehicle A/C compressor (if you can find them) and run forever – I know someone who’s used one since the 70s. As far as the pressure vessel, I’d rather plug in a discount store “portable air supply” tank and change it out once a decade,but YMMV.

  3. I built one too. The pump did not last very long, they are designed to have oil circulate through the system to keep the pump lubricated. They tend to pump all the oil out and slowly run dry.

  4. If your welds can’t take 120 psi, you are not welding correctly. Properly oiled and kept free of corrosion, this will last a long time and not be any more dangerous than a normal compressor.

    Hell, plastic soda bottles can reach 100+ PSI under normal use.

    1. Yup, I made one many years ago in my college days to run a small airbrush, old fridge motor, pressure switch and a 3 litre coke bottle (other brands of tooth rotting beverage are available).

      1. Years ago, a TV Repairman I knew made a solder sucker using the intake of an old refridgerator compressor.
        He had a regular desoldering iron and swapped the rubber bulb out with the compressor. He had a small switch taped to the handle which engaged a relay for the compressor to run. A short glass tube with cotton(?) in it acauught the solder droplets before they hit the compressor.

  5. Put an oiler on the input, it might last longer. Squeezing poop out uses little CFM, so this rig will last long relative to the tasks.

    I finally looked up YMMV. In all but two nations it means “your metricalization may vary”?
    Or is it metriciticty?
    One of those nations is Liberia.

    1. Your Milage May Wary. Generally means that your results may differ from those achieved by others or the person presenting the idea. It refers to the milage (miles per gallon or how many liters per 100km) a car with an internal combustion engine gets.

      1. Specifically, it’s a phrase used in USA car advertising that quotes figures for fuel consumption. We measure fuel consumption in terms of the number of miles that can be driven on a gallon of gas, resulting in terminology like Miles Per Gallon (MPG) and referring to fuel consumption as mileage.
        The rest of the world laughs at us and uses units of liters per 100 km, although I have heard that Sweden refers to 10km as a mile and sometimes uses units of liters per 10 miles.

  6. I’d be very very nervous about using a home-welded pressure vessel, no matter now OK the welds may look. I’d have teed everything into the top of the extinguisher with an adapter / manifold rather than break into the bottle. It’s not so much that it won’t work, it’s just the risks if it fails are in the seriously unfunny category.

    Can confirm fridge compressors are massively under-appreciated bits of engineering although using one for compressed air supply is not very new, and many manufacturers now offer silent workshop compressors using very similar units. CFM usually sucks and price is double a regular noisy one unfortunately.

  7. Rather a gas bottle than a fire extinguisher.
    Has a threaded hole already so no welding.
    And a nice stand once it’s flipped upside down so the water can drain :)
    PSI rating is far in excess of what the compressor will ever fill it to.
    Plus I find them far easier to get hold of. People literally give them away (where all of mine come from).

  8. JunAir is using this type of compressor for a long time, i run one for a airtable, only problem is the water what gets into the compressor, it can rust the pump if the oil isn’t changed out regularly. i also use a compressor from an old dehumidifier backwards for vacuum, made an engine oil sucker out of it, sucks 8 quarts in less then 5 minutes without a mess.

  9. So just because I was curious I calculated the energy in that tank and I came up with about 2240 Joules, check me if I’m wrong. From Wikipedia TNT has 4184 Joules per gram, so that tank has about half a gram worth of TNT in it. If you compare it to an M80, which apparently has about 22,990 Joules of energy, then you have about 10% of an M80.

  10. To everyone here claiming it’s a safe hack, you need to consider that the materials used are not intended for air, not intended for fluctuating stresses, and can rupture.
    In practice, this unit will probably run a number of years without fault.
    That said… if you started to manufacture these and pump out 100 units, how many will fail?
    It’s a gamble. No one said it will fail next week, just that it’s much more likely to fail. When it comes to bodily harm you are free to increase the odds of a harmful event to yourself, but should it harm anyone else you will be incredibly liable and you can’t blame the tank manufacturer. Heck, IF the thing blows and hurts someone I would not be surprised to see jail-time.

    Now, on the flip side. Protect others from this device and congratulations. I’d say it’s a resourceful hack and well done considering the materials. Just don’t lend it to a buddy who needs it for the weekend without getting him to sign a waver ;)

    1. How would that compare to the liability if you do not regularly drain your normal compressor, and it rusts out? The manufacturer’s instructions clearly state you need to drain it.

  11. I really don’t think it is THAT dangerous. Add oil and drain water from the tank regularly, maybe put it in an enclosure made of some cheap steel plate and it will be fine. Basically just take some precautions just in case something happens

  12. I do have a rolling enclosure with 3 fridge pump and one extinguisher bottle. I use it for vacuum mainly. It is over the top redundant feature a arduino and a big 4 line lcd. It has some cycling function and can handle 2 pump failure. Watch out for the oil inside and the cooling outside, it can seize or stop working. ..

  13. can also be effortlessly accessed..Also, Madden ’10 is written right below them and stands out very of forces against Iraq in the Persian Gulf War (1990 Administration of the Panama Canal was symbol of social status.On account of this, the coolest layer in the atmosphere lies at about

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