Homemade AirCompressor





Introduction: Homemade AirCompressor

This is how to make a cheap aircompressor from parts from the junk yard, for running airtools, filling tires and pneumatic spudguns.

Step 1: Safety

This isn't quite a set of instructions but more like a guide line. Because I made this from scrap, none of the parts are standard. Also take safety into account when working with compressed air, old tanks and rust out and explode with terrible results unless you know what your doing dont make one by one. So if you make one and it bursts and blows off you leg dont come crying to me.

Step 2: The Compressor

An air compressor has three main parts, a pump, a motor, and a tank. To get these you can go to you local scrap yard, they usually have a few scrapped compressors that can give you a pump and sometime a usable tank, if not with a bit of work you can use a AC compressor from a car, if either of these is unavailable harbor freight tools sells compressor pumps. For a motor you can get one from you local motor repair shop or from a scrapped washing machine, electric lawnmotor, or even a gasoline engine(this one would require a pneumatic clutch). And as for a tank you can use one from a old compressor, but I like propane tanks, you can get from walmart or ameri-gas(amerigas usually have old tanks that have the valves removed I bought my tank for $3)



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    46 Discussions

    I don't believe I heard anything about a check valve. A compressor pump should have a dedicated line with a check valve. This stops air pressure in the tank from flowing back in to the pump cylinder(s). Without it, the electric motor can draw an immense amount of starting current to fight the compression in the pump cylinder (when the tank is pressurized). It can either set off a breaker and/or potentially damage the motor.

    I read several mentions of oil/water separators in the comments. Having a separator on both the pump line and tank output is ideal. However, removing moisture doesn't work as easily as simply installing a separator or two. The hot, compressed air will wizz right through a separator and leave very little, if any moisture. You may find some oil residue inside, though. The air requires a means of cooling before hitting the separator to allow the moisture to be removed. The most effective way of cooling is with a parallel cooler such as an automotive AC condensor (or any AC condensor in general). The separator is just a neat compressor decoration and slowing air flow if it is not serving its purpose.

    This thing scares me. It looks like something out of "Mad Max"! Hopefully, this post doesn't encourage careless amateurs to put together their own air brushing machine/accidental IED.

    If you're really in need of an air compressor, you can purchase a used or refurbished one from a shop or even online. Look on Craigslist, buy or trade someone for a decent looking set-up, bring it home, and follow these steps to freshen up your air compressor: How to Maintain Your Air Compressor. Change or replace a couple things and it'll be good as new! (And not to mention, far safer than attempting to build your own!)

     I think a propane tank is a good choice probably a better choice than a water heater.  Propane tanks are designed with a 5 to 1 safety margin.  If the working pressure is 200 lbs than it is designed to withstand a 1,000 lbs of pressure.   At the low pressures required for air compressor storage I doubt the exploding tank scenario.  Metal is malleable.  I think the metal would tear before it shattered, at these pressures. If the tank does rust over a long period of time a weak spot , probably the bottom of tank, due to condensation would occur.  I think  the worst case scenario is the tank would rupture not explode.  Maybe it would take off like  a rocket for a couple of feet any way. 

    1 reply

    i've heard people talking about using CO2 tanks for air compressors and such, and thee only thing i've ever heard anybody day about the water and condensation is to take some good paint and swirl it around in there to cover it all up. otherwise... just be careful guys!

    i'm assuming you could, as long as you could airbrush with an ordinary air compressor. i got a kit for it at harbor freight for 12 bucks, and it works ok.

    Hello, all.
    I know everybody wants to do this as cheaply as possible, BUT.
    You *need* to spend a little, to save a lot.
    Commercial water traps and oilers are available, used or refurbished.
    Pressure relief, and 'pop-off', valves are cheap,
    compared to the damage that can occur.
    Not to mention the possible injuries.
    Cheaper to just oil the intake, regularly.
    A water trap, or what "metal_flowboard" said,
    will prevent water build-up in the tank.
    When I was an industrial maintenance mechanic,
    most pneumatic systems used a drain petcock on the tank,
    and a watertrap, or two, in the compressor's output line.
    One before the tank really helps it last,
    and another one before air tools, with proper lubrication keeps them running.
    Most of the valves, fittings, etc., can be scrounged or salvaged,
    but you *REALLY* need to buy a relief or pop-off valve.

    Have a GREAT day, neighbors!

    Awesome! This is probably the most useful thing that I've found on the internet today.

    If moisture in the tank is a problem,I've seen some air compressor pumps who's intakes have 1/4 inch threads, why don't you put an air desiccant?

     nice. would it be possible to use a gokart engine, remove all the gasoline parts and use that as a pump? because down here a gas motor is cheap and i can't find a pump anywhere. and anyone can buy a new compressor. any ideas?

    1 reply

    It's been a year since you posted this question, but I hope it helps someone.

    Yes. It is possible to convert an engine into a compressor pump. They are both piston machines working off of the same principles. It is about the same relationship that DC motors and PM generators have. For instance, there are people who convert antique pumps into hit and miss engines.

    On the other hand, people have also converted 4-cylinder engines into a pump/motor, "monoblock" combination by making 2 cylinders air pumps and the other 2 cylinders are left to run normally (with ignition mods, etc...)


    I was just about to make this but then I got an air compressor for xmas! So happy =)

    yes, there is an intake on all air compressord . you need to find it and pipe your synth gas into that . you could use a smaller propane tank and a propane converson kit for you car/truck and fill propane bottles with synth gas. let me know if you do this please .

    Adding more tanks in line should increase your capacity VS finding a larger tank

    I got two old air compressors Like this one but not as powerful And i did something like this but with my little stationary engine


    And i mounted it to a little butane can n made a compressor Not very good thouigh will try to post some pics if ican get some Its hidden away somewhere in the shed as i use my dads new Electronic one Lol its louder But safer

    Not a bad idea. There's a kit for volkswagen flat four engines that makes one side work as a two cylinder engine and the other as a air compressor.