Detailed tutorial to make air compressor in home environment and save money as well.

1. airbrushdoc.com http://airbrushdoc.com/tipstricks/homemade-airbrush-compressor/
DYI Airbrush Compressor
DIY: Homemade Airbrush Compressor
I’ve been surfing the net the other day trying to find some airbrush compressors and found out the
availability is very good so anyone can buy airbrush compressor online with no hassle. Of course
for a good one you will have to pay nice bunch of money. But at the same time I found really
interesting solution for those of you that prefer some DIY over shopping.
If you build it yourself it will help you to save some money. The whole “know-how” comes from a
Russian website so I will become translator for a while. The main issue for all the airbrush artists is
the right air pressure at the input of the airbrush gun. One of my issues at the start was money so I
was looking for a simple and at the same time cheap solution. As you probably already figured out
airbrush won’t work without compressor. I knew that there is one kind of compressor that most of us
can get for free or for a very little money. All I needed was just to find the way how to use it. What
kind of compressor am I talking about? …I’ll tell you later.
For now you can follow these steps:
Search
Surgery
Preparation
Utilization
Maintenance
Search
There is many places like basements, scrap yards, trash bins – places were people put the stuff
they are not going to use anymore. All you have to do is to look for a big, usually white box called
FRIDGE .
Yes, you’re right. Every fridge has a compressor, even the broken one. If you go to search for
a big white box don’t forget to take some tools; usually couple of screw drivers with different heads,
some combined pliers and spanner set as the size of dies in fridge can vary. If you’ve found your
patient you can start the second step.

2. Surgery
You don’t have to be a doctor to do that but you have to be careful and avoid any problems caused
by carelessness. First what you have to do is to cut off the copper pipes from fridge radiator.
DO NOT SAW IT!!! The sawdust would get into the pipes and your compressor will become “sick”
and die after a very short time.
Use only pliers and try to keep the pipes as long as possible as after all every cm matters. The
pliers will squeeze up the pipes at their ends and this will also prevent oil leak during the transport.
Some types of compressors used to have a metal plate with numbers sticked to pipes – do not take
it off.
At this point it is good to check the oil inside our trophy. Pour some oil on a piece of white paper. If
you see any silver particles in the oil you can stop the whole operation and memorialize the poor guy
with a minute of silence. If the oil is clean you’re good to go.
Very important thing – the compressor is not the only one big piece of metal junk you’re going need.
We will need one more part – start relay. It’s small black or sometimes white caddy separately
mounted near compressor. It has some cables connected to it.
I would recommend to make a drawing of how it was mounted and connected before you take it off.
Some types of compressors have their relay directly on them, so you won’t need to unmount it. But
you surely will have to cut of two input cables.
Once you have unmounted everything don’t forget to take all the pieces with you.
Preparation
At this point you have to arrive home. Tired, dirty from oil and perhaps with some scratches but it
does not matter because you have the trophy .
Now first of all you have to check if your compressor is still alive. We have to do the launch
check.
DO NOT turn it on now – READ FIRST!
Put the relay back on the compressor according to your drawing you’ve made before. Relay has to
be oriented exactly the same way as it was on the fridge as the relay depends on earth gravitation.
Otherwise it may cost you the relay or even the engine inside the compressor might burn
out.
Now connect the temporary cradle to the input of the relay and don’t forget to use electrical tape. I
don’t think you want to die. This is how the draft version looks like:
Next use the pliers and release the squeezed pipes and
leave them opened. When everything is ready connect the
plug into the mains socket. The launch itself could be very
loud depending on the power of the unit but it
understandable so don’t get scared. If you hear the engine
and it is pretty quiet then everything should be fine. The
pipes will suck and blow the air – you have to find out which
one deos what. You don’t have to leave it on for a very long
time as the main thing right now is to make sure that it is
alive. If the engine didn’t start or if it started but than after

3. short time went off the things aren’t looking good. If you
have some experience and electric multimeter you can
check what exactly is wrong and more skilled of you could
even try to fix it. Otherwise forget about the whole thing and
start looking for another one. If it’s working skip the
checking process.
Checking: Take off the relay and check the coils of engine for short circuit. They
should have a small resistance between them even in different combinations. If at
least one of the coil doesn’t show anything it means that we hold a dead body of
the compressor. If every coil has some resistance you have to check the relay and
clean it. Carefully open the relay box and clean the contacts with fine sand paper.
DO NOT BEND OR BREAK THEM!!! And do not grind them to much. Now close
it back and try the whole launch again. If it didn’t start or if it keeps going off by
itself than I’m very sorry about that (if you are not using original relay from another
fridge then switching off can be caused by engine being too powerful for the relay
and you have to look for another relay – that’s why you ment to keep the metal
plate on the pipes, it will help you to find the specific relay for your engine).
I hope that you didn’t get into any trouble and everything is working. Now we can start to build our
machine. Everyone has his own equipment, facilities and resources but I’m going to point out what
you’re going to need.
Visit your closest car parts shop and buy this:
1L of motor oil 10w40 or other semi-synthetic motor oil. If you can get a 500ml package it is
going to be enough.
oil and fuel resistant durable armed rubber hose about 1m long and 4mm of inside diameter. It
won’t hurt to take a small piece of copper pipe to try it on in the shop just to be sure.
6 metal hose clamps for the rubber hose with diameter just a little bit bigger than the hose.
PVC hose for windshield screen washer. It’s half transparent hose (some are even armed but
we don’t need those). Choose your own length as your comfort will depend on it. I would
recommend at least 2m.
Two filters for fuel filtering – one for petrol (gasoline) and one for diesel fuel. Visually they are
different as petrol has a paper harmonica inside while the diesel one has a synthetic net.
thick silicon (oil and fuel resistant) sealant. Thin, black silicon sealant is not very good for the
job.
Than go to electrical shop and buy :
power cable with double isolation and at least 1.5m long.
on/off switch closed type
lag screws size 3.5×16 or 3×16
That’s all you will need at the moment:

4. Next we have to change the oil. Why?
Read next article on this topic.
At this stage there is a technical
question: Which type of compressor
do you have in your hands? By shape
there is two types – cylindrical and
casserole type. First one is practically
extinct as production of this type
stopped at the end of 70s, but if you
manage to find one and it’s alive you
are very lucky. The pressure on its
output is higher than on casserole
type. So how do we change the oil?
The cylindric one has a big screw-
bolt. Unscrew it and drain out the oil
into some bowl so you can later measure the volume of the oil. Depending on the type of cylinder it
might be something between 300ml and 500ml. Then screw the bolt back and don’t forget to seal it
using silicon sealant.
With the casserole type it is a bit more complicated as there is 3 pipes sticking out of it. Two are
pumping the air in and out, the third one is for oil. Again do not saw the pipe!!! And remember after
you have drained the oil out do not turn the compressor on, you have to pour the new oil in first.

5. On the second picture is
the same compressor
however a bit restored and
with new oil already in. As
you can see I’ve used
rubber hose on the oil pipe
outlet.
For this type of compressor
you will need about 250 –
350 ml of oil. After that
screw the lag screw into
rubber hose and put some
rubber seal under the
screw.
I know that there are going
to be some people that are
going to feed the oil to
compressor during the run. I
do not recommend to do
that.
Oil has to be changed before you turn on the compressor as running it without oil is the same
as to kill it right away.
Second of all if you pour to much oil (in pistons mechanics) you risk something called hydraulic hit.
It happens when into space above the piston comes more fluid that it can compress (fluids are
almost not compressable). As result we destroy the whole piston system. I hope you get the point.
Lets continue. On the next image you can see how it is going to be set.

6. If you connect everything according to this drawing you’re going to get fully working airbrush
compressor. To make it more practical you have to fix everything on some kind of stand or table that
will minimize the possibility of breaking it. I have used a piece of timber board. The size of the board
depends on the size of the receiver you are going to use. Receiver is a big white bottle you have
seen on the photos. Why do we need it?
It smoothes the pulsation of air coming from compressor so at the output you will get a smooth
fluent flow of air without pulsation.
It also catches the drops of oil and exhaust from compressor.
For this type of compressor we will need receiver with capacity of 1 – 2l. Practically you can use any
hermetically firmed reservoir. I would not recommend to use plastic or glass bottles as under the
pressure they can blow off and cause injury. I’ve seen some people using an old empty fire
extinguisher as the receiver but it requires more skills and tools to accomplish something like that. In
our case we use old water reservoir from a car. It is made of polyethylene that is more firm that the
plastic bottle and it’s hard to destroy even with sharp knife. Even if it blows off it does not make a
massive explosion as for example glass does.
How to make a receiver? When you have your bottle ready take the lid off and drill two holes into it. If
you can get 2 copper pipes something like 15cm each (if the pipes on the compressor are long
enough you can cut those off but leave at least 10cm on the compressor). These pipes are suppose
to fit into holes on the lid you’ve drilled before. After fitting put some epoxy resin on the inside of the
lid but not too much so you can screw the lid back on the bottle. Do that only when the epoxy is dry.
Don’t forget to use some silicon sealant between the bottle and the lid. When you will be fitting the
pipes make sure they are very close and their ends are exactly as on the drawing (output pipe is
shorter and the end is positioned higher).
After you have all the parts ready you can see what size of board will you need for the chassis. Don’t
forget that compressor needs some cooling so leave some more space around it. I used timber
board with size of 30cmx40cm. The finish of the panel is up to your own taste. I’ve also used rubber
pads to prevent the stand from moving during the work process and it absorbs the noise as well. I
hope you didn’t forget all the screws at the crime scene as now you’ll need them to mount your
compressor to the timber board.
I would recommend to mount the receiver exactly as you see below:
of course as belt you can use anything,
for example rubber, leather but it has
to be firm.
And here is an example of how to fit
the relay, switch and cable:

7. When you finish with the electrical part we’re going to fit the pneumatic system. At the inlet of the
compressor we connect petrol (gasoline) fuel filter using short rubber hose and 2 metal clamps.
Someone might say this is useless but I say go for it anyway, it’s cheap and you won’t have to worry
about dust getting into your compressor. Very important thing is not to get any oil into that filter as it
won’t do any filtering anymore.
Next, with a piece of rubber hose and other two clamps connect output pipe of the compressor with
input of receiver. On the output of receiver put another piece of hose and fix it with a clamp and
other end of it will hold diesel fuel filter fixed with last clamp we have left. Be very careful when fitting
the receiver and make sure you don’t break the lid.

8. Diesel filter is almost last element of our unit. Now fit the PVC hose. Usually the diameter of that
hose is smaller then output of the filter so it is very difficult to put it on. If you have white spirit put the
end of the hose into it but not deep (5mm is enough). After that it won’t be a problem to fit that hose.
Fit the hose to timber board and it’s done. Congratulations if it works well, but I would recommend to
start using it only after couple of days after silicon sealant is completely dry.
Utilization
Nothing special about that.
The only thing to remember – do not let your compressor to overheat.
Usually the temperature rises to 40-45°C in 25-30 minutes of continuous work. After that time you
should let the compressor take a break. Otherwise you will have to regulate the air pressure.
Some types of compressor can produce more air than we need for airbrushing. In that case we will
have over-pressure in the hoses, filters and receiver and the compressor itself will be overloaded

9. what can lead to fast overheating. If this is the case, you’ll have to get a reducer. The reducer has to
be placed on the input of the compressor not output, as that would also cause overloading. By
placing the reducer on the input we reduce the capacity of the air coming in – that regulates the
pressure. So what can we use as the reducer? Any calibration pipe placed on the input of petrol
filter will work as reducer. You can make one yourself or visit pet shop and buy an aquarium valve
reducer. It’s cheap and very useful as you can regulate the pressure during the work.
Maintenance
This process is not complicated but to do so you will have to take off some parts. Of course you
don’t have to maintain at all but it will definitely extent your compressor life.
The steps you have to follow:
Changing the oil
Changing the filters
Cleaning of the receiver
Oil, even the best one, is loosing its properties and goes dirty with the time. So regardless of
worked hours I recommend to change oil once a year.
When you’re going to do that, take off the compressor all the hoses, unscrew the screw from the
filling pipe, drain the oil out and pour new one in as you did during the build. Remember not to turn it
on when it’s empty. While you have all of the hoses off exchange also filters and drain the oil if any
from receiver. Do not pour that oil back into compressor.
Fit everything back and that’s it.
The End!