Homemade Compressor for Airbrushing

Hi. I'm Joe, a 55 years old geophysical engineer and I have a hobby for aircraft static modeling, so I'm looking for ideas to make a homemade tank compressor using a refrigerator type compressor for airbrushing purposes.

The piston and diaphragm types run hot very easily and are too noisy and I need a quiet environment to work.

In the recent past I build up one but I had trouble with an oil mist in the air flow no matter what type of oil filter I used.
I want to know what went wrong in the design and have the opportunity to correct it. :headscratch:

I would appreciate and welcome any ideas.

Thanks

Hi Joe - welcome to HomemadeTools.net :welcome:

Interesting build! I'm going to move this discussion into our Tools in Progress subforum so that you can get some good ideas.

Quote:

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Originally Posted by JMPBautista

Hi. I'm Joe, a 55 years old geophysical engineer and I have a hobby for aircraft static modeling, so I'm looking for ideas to make a homemade tank compressor using a refrigerator type compressor for airbrushing purposes.

The piston and diaphragm types run hot very easily and are too noisy and I need a quiet environment to work.

In the recent past I build up one but I had trouble with an oil mist in the air flow no matter what type of oil filter I used.
I want to know what went wrong in the design and have the opportunity to correct it. :headscratch:

I would appreciate and welcome any ideas.

Thanks

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Hi Joe
I to have been unsuccessful in eliminating oil contamination from one of these fridge compressors, they are just not suitable for spraying as they run in an oil bath (ok for workshop use).
Your best bet for a silent environment may be a slave tank filled where noise is not a problem, maybe from a car tire inflater this could be an old fire extinguisher or don’t laugh a car inner tube I remember my father spraying the wing of his car by this method using my Celspray gun with me on the foot pump, turned out pretty good too.
As I recall airbrushing only needs about 10 psi at very low volume so an air reservoir at about 40 psi should last a while.
I am sure you will get more suggestions.
Regards
Olderdan

I saw a small air brush compressor made out of a foot operated tire pump being powered by a windshield wiper motor as I recall for a tank the guy was using a 2ltr drink bottle he had everything mounted in a large aluminum brief case Gel battery and all supper quiet and portable built in charger as well

Joe; Your idea of the refrigerator compressor won't work because of the oil problem you already noticed. It's the design of the compressor to pump a little oil as it operates, actually you would run it out of oil eventually. I don't know a lot about air brushing. But it sounds as if you could purchase an refillable air tank, (big box store). I've made them out of old "r" type refrigerant tanks, a 50 pounder is ideal, but I don't know if the make them that size anymore. And than you can fill them at a gas station, their compressors are usually big enough to give you all the air you'd need. Pedro Contrero

Joe,

I'm a model builder (static and model trains) and what I found works best for me is a small CO2 tank. You can buy or lease one from a home brewing shop and they will supply dry air for quite a few models. I have my regulator set around 15 psi and it seems to work very well; a bonus is no noise from a compressor.

Lou

Quote:

---

Originally Posted by JMPBautista

Hi. I'm Joe, a 55 years old geophysical engineer and I have a hobby for aircraft static modeling, so I'm looking for ideas to make a homemade tank compressor using a refrigerator type compressor for airbrushing purposes.

The piston and diaphragm types run hot very easily and are too noisy and I need a quiet environment to work.

In the recent past I build up one but I had trouble with an oil mist in the air flow no matter what type of oil filter I used.
I want to know what went wrong in the design and have the opportunity to correct it. :headscratch:

I would appreciate and welcome any ideas.

Thanks

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USE A DIAPHRAGM COMPRESSOR OR OILLESS COMPRESSOR. DIRECT DRIVE COMPRESSORS CAN BE NOISY, BELT DRIVEN COMPRESSORS RUN SLOWER AND QUIETER.

WHEN YOU COMPRESS A GAS ITS TEMPERATURE RAISES AS YOU ARE PUTTING THE HEAT OF THE GAS IN A SMALLER VOLUME SO YOU PUT THE HEAT CONTENT INA SMALLER VOLUME AND THE TEMPERATURE RISES. THEN YOU ADD THE TEMPERATURE OF THE COMPRESSOR SO YOU SEE A CONSIDERABLE TEMPERATURE RISE.

REFRIGERATION AIR COMPRESSORS ARE DESIGNED SO THAT THE COLD REFRIGERANT GAS ENTERS THE CRANKCASE FIRST, THEN IS ROUTED TO THE INTAKE VALVE, GOING INTO THE CYLINDER ON THE PISTON DOWN STROKE. IT IS COMPRESSED ON THE UPSTROKE AND IS ROUTED TO THE CONDENSER AS A HOT GAS. CRANKCASE OIL IS CARRIED ALONG WITH THE GAS AND TRAVELS THROUGH THE ENTIRE SYSTEM AND BACK TO THE COMPRESSOR.

IF YOU ARE USING AN OLD PISTON, NOT A HERMETIC COMPRESSOR, ONE WAY TO SEPARATE THE OIL FROM THE GAS WHEN USED AS AN AIR COMPRESSOR IS TO EITHER USE AN OIL/AIR SEPARATOR WITH A BLEED LINE FOR THE OIL TO RETURN TO THE INTAKE OR CRANKCASE.

THAT MIGHT NOT DO A GOOD ENOUGH JOB SO AN ALTERNATIVE WAY IS TO SEPARATE THE INLET AIR FROM THE CRANKCASE, BRING THE AIR IN THROUGH THE INLET SERVICE VALVE RIGHT TO THE CYLINDER HEAD. THE CRANKCASE MUST BE VENTED TO THE ATMOSPHERE OR PRESSURE BUILDUP WILL PUSH OIL PAST THE PISTON RINGS.

HERMETIC COMPRESSORS WILL PUMP OUT ALL THEIR OIL, SO YOU MUST SEPARATE IT FROM THE COMPRESSED AIR AND SEND IT BACK TO THE CRANK CASE.

A SINGLE STAGE COMPRESSOR MUST NOT TO MAKE MORE THAN 150 PSI, 90 PSI IS BETTER. IF YOU EXCEED 150 PSI THE OIL VAPOR IN THE COMPRESSED AIR MAY IGNITE DUE TO THE HEAT OF COMPRESSION, COMPRESSION IGNITION LIKE IN A DIESEL ENGINE. THE BLAST WILL RUIN YOUR DAY, MAYBE YOUR HOUSE.
.

Back in the early 70's I worked at a place that had a huge old air compressor used for impact guns and tire machines. As you might imagine the old compressor spewed lots of oil. We wanted to paint a car so we needed to good air supply. We found a filter that held a whole roll of toilet paper. (have not see one like it since) it worked really well, absorbed all of the oil and moisture, then a regular filter collected the little paper particles that came from the TP. Worked very well.

Once while working part time at a full service gas station an older gentleman drove up in his 48 or 49 chevy complaining that since he had changed his oil his oil pressure was continuously getting lower and lower. I had him park his car over the pit then I pulled the top off the filter only to find a roll of toilet paper. When I asked him about it he said that the old filter looked like that was what it was so he thought he would save the 2 dollars of the cost of the filter. It nearly cost him his engine. I drained his oil and pulled the pan the screen was nearly blocked. So I cleaned everything put the pan back on installed a proper filter filled the crankcase with ATF started the car let it run for a while drained it pulled the pan again cleaned the screen and the pan put everything back together changed the filter and re filled with his favorite brand of oil
For what it cost him he could have had his oil changed properly at the station every 3 months for 2 years, but he did become a regular customer
Toilet paper as an air filter restrictive but good just catch the chunks, toilet paper as an oil filter BAD.
there are several heavy equipment fuel filters that use a cartridge made out of wound string you can even get house hold water filters that use a string wound cartridge
I believe that Grayco still makes an oil separator air filter that uses a string wound cartridge

Hi Joe

Lou N has the right idea. Skip the air compressor and use a CO2 tank. I have used one for 50 years and it works great!

It is quiet and the CO2 is clean and dry. You will need to get proper sized fittings to hook it up to your airbrush/spray gun. Most hardware stores will have the fittings you need. Just make sure you get a good regulator.

Jay

https://www.harborfreight.com/2-gall...yer-95690.html
Attachment 18100
$14.99
Super quiet, get buff
https://www.harborfreight.com/1-6-hp...sor-93657.html
Attachment 18101
$69.99
Still pretty quiet, the usually quality at a great price.

Hey, Joe:
I would not try building. As an engineer, you know how complex it gets. Better to buy and let someone else build it for you.
I've been airbrushing pro for 36 or so yrs. Since I use them hard for 8-12 hrs a day, I go with the oil-cooled 1 HP or so industrials that they sell you for running nail guns, etc. Too loud for you,I guess, tho I have built boxes out of plywood and lined with several layers of old blanket stapled to inside; always have a small fan blowing air through the box to cool it or you'll burn up the pump. It will knock off half or so of the sound. Also, after building them, I sometimes drape many layers of thick clothing on top and this helps more. ALSO, lay a layer of something ( those stiff foam rubber floor tiles are great) on the floor, set the compressor and box there. The floor transmits a LOT of noise, especially to your downstairs neighbor. Even better, put it in another room and run a hose to your workplace. If you must have silent, you can buy them at chicagoairbrushsupply.com or dixieartcom. Not cheap, but they work. Also, I've noticed at Menards (Lowes, etc), they sometimes, not often, have compressors that use small almost silent pumps and they are reasonable.

Right now on amazon there is a California Air Tools CAT-1P1060S for $104. Gets good reviews. I would put a small fan as close as possible to the pump and blow LOTS of cold air on it to extend life.

Honestly the last time I used a silent fridge type (Air Force brand, a first mover in this area), I burned it up in a few weeks of 12 hr days. Swore them off. Good luck.
Mark

I would buy a compressor. The time and effort and cost will be a wash in the end. As for noise I buit a box out of 3/4 plywood. And lined the inside with Comercial carpet squares (2 layers). You can get them for just about nothing. Or go by any construction site and ask for some. Or any building that you know has raised flooring in it. Ask the facility manager about getting some. I stapled mine to the inside. I also I stalled (2) 120 Vac fans with a switch to blow air in the box on the opposite side I built a box along the far side of the fans with a hole at the top edge and a hole on the bottom to vent the air along with baffles lined with the same carpet. Think of the outside box like an upside-down periscope. This made a huge difference in the sound. It dropped the Db levels down 30 db. Density in the materials is the key to sound damping. If you can't get carpet squares get rock wool from any large construction store. The problem with rock wool is that it is very thick and you will need to build you box mucH larger to accommodate for it. You will need to build the box 3 times the volume of your compressor to allow good air flow and proper cooling.
As for a compressor I would get a belt drive compressor. They are much quieter. And can produce alot more volume and run less. The majority of the noise comes from air intake you could re-pipe it to a sound dampened box to cut your noise down even more.

Our Air Compressors category for ideas: Homemade Air Compressors - HomemadeTools.net

Hi I'm a new member. Lou is correct CO2 is an excellent choice for your project, dry, safe and cheap. An excellent source for CO2 is a local welding supply store. They will also have the regulator you will need for the CO2 cylinder. You will want one which has a PSIG gauge on it for the downstream pressure you will want to set, do not get the regulator that has flow in CFH or cubic feet per hour. Most regulators will have 2 gauges, one for the pressure in the cylinder which will be about 750 psig, and one for the flow pressure you set. CO2 is sold by weight in pounds from very small 2 pound cylinders up to 75 or even 100 pound cylinders, this is the weight of the liquid CO2 in the cylinder, not the total weight of cylinder and product. Also there are 2 types of cylinders, one for gaseous with draw, the one you want. The other is for liquid with draw, mostly used for fire suppression. Liquid CO2 converts to cubic feet of gas at a ratio of 1 pound of CO2 to 8.7 cubic feet of gas. Probably a good size for you would be a 20 pound cylinder, should last a long time is portable, requires little space. Also remember the product is priced higher at smaller size cylinders. In other words the cost of a pound of CO2 in a five pound cylinder is greater than the cost of a pound of CO2 in a 20 pound cylinder. it takes as long to fill a 20 as it does a 5 and so on. If you see a cylinder on craigslist for sale you will want to know if it is in test, they are tested every 5 years and the date is stamped into the neck of the cylinder. Also make sure it has clear title, verify with a local welding supply they will fill it, many stolen cylinders out there. I was in the industry for 39 years and have seem many people do this.
Thanks
Paul