Professional Results From Cheap Air Compressors

The portable air compressors sold at big box hardware stores like Lowe’s and Home Depot are perfectly suited for the jobs they’re advertised for: namely throwing some nails into the wall or filling tires. But if you try to respray your car with that $50 Black Friday pancake air compressor, you’re going to have a bad day. The relatively small amount of air they hold is almost guaranteed to be contaminated with oil and moisture, making it unsuitable for painting or even just blowing the dust out of electronics.

But all is not lost. [Stephen Saville] has done an excellent job documenting his work to turn these low cost homeowner-grade air compressors into something suitable for spraying auto body panels. But even if you aren’t looking to put a sick pearlescent finish on the family minivan, these tips are worth checking out. From increasing the usable volume of air in the system to separating out contaminants, these modifications can unlock a whole new world of pneumatic projects.

The big one (literally and figuratively) is the swirl tube [Stephen] builds out of an old CO2 cylinder. The idea is that this will centrifugally clean the air, not unlike a cyclonic dust separator. As the air enters the top of the cylinder and spins around, contact with the cold metal will cause any moisture to condense out and collect down at the bottom. Oil and other particles in the air should also get spun out, leaving a central column of cleaner air. The collected water and contaminants at the bottom can be occasionally purged out by way of the cylinder’s original valve.

With a source of clean and dry air sorted, [Stephen] next wanted a way to get it around his shop. Using scrap metal pipes he puts together a system that not only gives him air where he needs it, but also increases the volume of compressed air he has available. By using large smooth metal pipes rather than something like flexible rubber hose, the plumbing puts very little resistance on air flow. The pipes therefore can be considered something of an extension of the compressor’s primary tank.

In the video after the break, [Stephen] shows off his new air system by laying down a very nice looking coat of paint on a car hood, but he also goes through the whole build process if you want to see the nuts and bolts of his system. He gives some great tips on welding and working with dissimilar metals which are worth the price of admission alone.

Outfitting the workshop with an integrated compressed air system sounds like the perfect second project to tackle once you’ve got the built-in dust collection system up and running.

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Breathing Underwater Using Wind Power

As hackers, our goal is to reuse something in a way in which it was not intended and [Rulof Maker] is a master at this. From his idyllic seaside location in Italy, he frequently comes up with brilliant underwater hacks made of, well, junk. This time he’s come up with a wind-powered pump to move air through a hose to a modified scuba mask.

The wind turbine’s blades look professional but you’ll be surprised to see that they’re simply cut from a PVC pipe. And they work great. The air compressor is taken from a car and the base of the wind turbine’s tower started life as a bed frame. As you’ll see in the video below, the whole setup is quite effective. It would have been nice to see him using his leg mounted, beer bottle propulsion system at the same time, but the air hose may not have been long enough to make good use of them.

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Repair Job Fixes Compressor, Gets it Online

We’ll never cease to be amazed at the things people try to put on the Internet of Things. Some are no-brainers, like thermostats, security cameras, and garage door openers. Others, like washing machines and refrigerators, are a little on the iffy side, but you can still make a case for them. But an IoT air compressor? What’s the justification for such a thing?

As it turns out, [Boris van Galvin] had a pretty decent reason for his compressor hacks, and it appears that the IoT aspect was one of those “why not?” things. Having suffered the second failure of his compressor’s mechanical pressure switch in a year, and unwilling to throw good money after the $120 that went into replacing the first contactor, [Boris] looked for a cheaper and more interesting way to control the compressor. An ESP8266 dev board made interfacing the analog pressure sensor a snap, and while he was at it, [Boris] added a web interface with a nice graphical air pressure gauge and some on-off controls. Now he can set the pressure using his phone and switch it off in the middle of the night without going outside. That’s an IoT win right there.

No air compressor? No worries — build your own from an old fridge. The non-IoT kind, preferably.

Fridge Parts Make Air Compressor That’s Easy on the Ears

Compressed air is great to have around the shop. The trouble is, most affordable compressors are somewhere between “wake the dead” and “the reason Pete Townshend is deaf” on the decibel scale. But with a little ingenuity and a willingness to compromise on performance, you might find this ultra-quiet, ultra-cheap air compressor a welcome way to keep the peace in your shop.

Yes, this compressor under-performs even a Harbor Freight pancake compressor which can be had for $60 and is ready to work right out of the box. In fact, [Eric Strebel]’s design sort of requires you to buy an air tank, and the easiest way to do that might be just to buy the compressor in the first place. But the off the shelf unit won’t run as quietly as this one does, what with a refrigerator compressor swapped in for the original motor and pump. There’s also a silencer on the input side, fashioned from a shaving cream can and some metal wool. The video below shows the build, and the results are impressive, at least from a noise perspective. Whether it suits your shop depends on your application – it certainly won’t run an impact wrench, but it’ll blow chips off your mill or dust out of your computer.

Fridge compressors are a natural starting point for air compressor builds, like this fire extinguisher based design, or this high-pressure tandem compressor. But if you need high flow and don’t care about the racket, try ganging four HF compressors in parallel.

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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.

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High pressure air compressor using a pair of refrigeration compressors

[Ed] from Ed’s Systems, aka [Aussie50] took some time to demo his high pressure Frankenstein air compressor he stitched together from two refrigeration compressors. The two Danfoss SC15 compressors can produce upwards of 400psi and can run all day at the 300 psi range without overheating. The dual units may get up to pressure quickly considering the small accumulator “tank”, but high CFM isn’t the goal with this build. [Ed] uses the system to massacre some LCD panels with lead, ball bearings, and other high speed projectiles shot from a modified sandblasting gun. Just a bit of air at 400 psi is all you need for this terminator toy.

Don’t think the destruction is wasteful either; [Ed] strives to repair, rebuild, reuse, repurpose and a few other R’s before carefully separating and sorting all the bits for recycling. This modification included lots of salvaged hardware from older teardowns such as high pressure hoses, connectors, accumulator and pressure cutoff switches.

At first it seems strange to see something engineered for R22 refrigerant working so well compressing air. Morphing refrigeration systems into air compressor service is something [Ed] has been doing for a long time. In older videos, “fail and succeed”,  [Ed] shows the ins and outs of building silent air compressors using higher capacity storage tanks. Being no stranger to all variations of domestic and commercial refrigeration systems, [Ed] keeps home built air compressors running safe and problem free for years.

Don’t think this is the only afterlife for old refrigeration compressors, we’ve seen them suck too. You’ll get a few more tidbits, and can watch [Ed’s] video overview of his home built compressor after the break.

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Star Trek inspired pocket doors

Do you have enough confidence in your hacking abilities to build a project into the walls of your home? [Marc] used his skills to build an air-powered sliding door for his bedroom. It is similar to the sliding door you’d find on the Enterprise, two sections that slide nicely into the wall to let you pass. Although the picture above shows the internals, he followed through and ended up with a fully finished room that looks fantastic. A compressor in the attic provides the pressure necessary to move the door sections. It is automated, but uses a button press or keypad combination to run instead of detecting motion. Of course, since he’s using a PIC microcontroller to drive the system there’s always room for future changes. Check out how great the finished look is in the video after the break.

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