Quiet compressor for everybody

Tools, Techniques, and Reference Materials Painting and airbrushing
1

Hello!

I keep reading questions about quiet compressors. Every time I do, it makes me want to say - they’re everywhere, you just have to take a little look around. Please, take a look at what I built usng a compressor taken out of an old refrigerator:

I also used an old gas bottle that was laying around my garage, and also some fancy fittings that I bought especially for this ocasion, because I like working with high quality material. But If cost was the factor, I’d say you could put up something similar for about 100$, provided you could get a fridge compressor for free. If you could get your hands on an old AC unit, you’d get a compressor, a pressure switch and a tank - and chances are at least some of the components would be in an usable condition.

And how quiet is it? I don’t have a dB reading, but when I took it outside once, I wasn’t able to tell if it’s operating or not by listening to it - the slight wind noise and cars going down the street half a mile away completely masked the compressor noise. In a hobby room, you stop hearing it when you turn the radio up a little. And it turns on only every now and then, to top off the tank.

So if anybody is playing with a thought of building a compressor by his own, I say, try it, it’s worth it! Thanks for reading, and have a nice day

Paweł

2

Hats off to you, Pawel!

For those who are interested in doing what Pawel did, get a copy of the Osprey Modelling Manuals #6: “Airbrush Painting Techniques”. There is a detailed article on building a DIY compressor with step-by-step instruction and parts list. However, it is not for the faint of heart.

Unless you get your hands on some surplus items such as the refrigerator compessor and pressure switch etc., the component cost will be out of sight.

I think that the easiest way to get a refrigerator compessor is to buy a dormitory size refrigerator at Walmart. I have check into a few replacement refrigerator compessors. They are expensive.

Anyone else has done the same thing?

3

Pawel, how long have you been using this setup? Have you had any issues with duty cycle and the compressor being able to keep up with air demand? My concern is that, a refrigerator compressor being designed for a closed system (the refrigerant circuit), maybe it’s not robust enough to deal with a huge drop in pressure from a more open compressed air system like most airbrushes use. Do your tanks do a good job of compensating for that? What do you think is the total pressure drop for each time you use the airbrush?

I’ll take a cheap DIY setup anytime over more expensive options. Thanks for posting this.

4

Thanks a lot for your comments, gentleman!

keilau - you’re right, the biggest challenge, and at the same time the greatest opportunity, is getting the compressor itself. If you want to buy it as spare part, it’s going to be expensive! But you can also ask a refrigerator repairman, or watch around your neghbourhood - how often does a refrigerator get dumped? I say it happens often, and the compressor is mostly OK. I got this compressor from a repairman for an equivalent of 15$. A brand new pressure switch would cost me about 40$, and again this much for a brand new reductor. If you skip new, shiny fittings, I’m sure it can be done under 100$. for a factory-built compressor of this class, I would have to pay at least 1000$, if it was new.

dirkpitt77 - I’m using this particular one for half a year now. I didn’t really time it yet, but I estimate the compressor needs like three minutes to fill the tank up to 6 bar. I have the regulator set to 3 bar, so when I’m preshading (that’s what I do the most), the duty cycle of the compressor is less than 50%. But I also have another rig of similar construction, and I use it for about 20 years now. I added more oil to it about two times, and did two major modifications during this time (one was fitting a pressure switch, the other was adding a reductor). So at the beginning I had a russian airbrush that had no air valve and the air was flowing through the airbrush all the time. The compressor didn’t have problems with supplying this much air, and was running for about an hour at a time. It got a little hot when operating like that, though. After I fitted the proessure switch, and started using a Paasche airbrush with air valve, the duty cycle is always low enough, for the compressor to stay cool.

So - I understand your concerns, and I have to say it also depends on the type of compressor a little, but it’s been successfully tested by me with different airbrushes, like the legendary “Russian” (without air valve), a copy of Iwata, simple, single-action airbrush (siphon fed, air valve only), and Paashe VJR.

Thanks for reading, have a nice day

Paweł

5

That’s good to hear. I have been looking for a quieter option for myself. This might inspire me to build my own as well.

Excellent info, Pawel. Thank you again!

–Chris

6

Chris - if you have any questions, or problems with your build, please don’t hesitate to post them here, I’ll try my best to help building a machine like that! Good luck, and have a nice day

Paweł

7

These fridge compressors work great, Iv’e made two and even scored a old Jun Air which is fantastic.

Keep in mind if you build your own you will be playing with mains voltage which can kill you so please if your not confident with electricity get someone that is to do it for you or at least check your work.

Mick

8

Good work Pawel, glad the device has worked for y’all so long.

Since 1966 have bought at least 10 compressors with tanks or no, biggest was 10 gallon piston monster 27 years ago, made Devil’s Own Noise; have bought three since c.2012.

I’ve sworn off the pistons, incredibly noisy plus heavy, diaphragms I’ve bought since 2004 now last as long, half the noise generally. The 2 gallon Husky cheapie got now is the best compressor I’ve ever owned, don’t need to pump the tank till its empty thanks to my being more “economical” with air brushing work, saves on diaphragm & motor wear.

9

Mick - thanks a lot for your comment. You’re right, you have to watch out when working with electricity - regardless if you’re experienced or not, carelessness can kill you, and/or somebody around you. But it also worth noting, that compressed air itself, as a form of storing energy also can be dangerous - if only blowing some debris into your eyes, it can also burst some installation sending shards through the air, or in extreme cases kill you through air embolism - putting air into your blood vessels upsetting your blood flow. Whatever you do, you have to look out.

Retired - Thanks a lot for your kind words! The good thing is if you already have a compressor and it’s busted, you can re-use a lot of the machine - the tank, the pressure switch, the regulator, the quick-disconnects - and replece the actual compressor with one from an old refrigerator. This way you get a nice, quiet and reliable machine for almost nothing. When building from scratch the items mentioned above can cost quite a lot of money.

Good luck with your compressors and have a nice day

Paweł

10

If you are really interested in the sound level most smart phones have a sound measuring app.

11

Hello!

I’m bringing back this old thread to show you another DIY “fridge” compressor. The thing here I got the “heart” of this setup from my father somewhere around 1993 - that’s a long time ago, and I’ve been using this baby pretty much constantly since.

Unfortunately a few weeks ago I left the compressor on (the pressure switch shut it off and I planly forgot it - happened many times before) - but this time an old rubber hose burst, the pressure switch kicked in, the compressor got hot, puked out all the oil through the leak and seized while I was away…

I had to look for a new fridge compressor and I noticed it got harder than it was some years ago. Back then the fridge repair companies had large batches of used components, nowadays they throw it all away. Fortunately I have found a company that cuts apart frigdes that were damaged in transport and so I got a new compressor.

Here’s how my old setup looked like:

"Fridge" compressor by Pawel

On the new compressor there was a “thermal” starter circuit - that’s a bad thing for airbrushing as this circuit needs to cool off for about a minute or two after stopping the compressor before you can turn it on again, no go. Finally I replaced this with an electronic circuit of my own design - and now I can turn the compressor on and off as often as I want, or as the air runs out. To house my electronic circuit I decided to clean up the design and house all the switches in one housing. Here’s how it turned out:

"Fridge" compressor by Pawel

I also added a paper fuel filter on the air intake to act as an air cleaner - and the side effect of that was that the already quiet compressor got noticeably more quiet still. When it’s pumping it’s really as quiet as a fridge. The hiss of air running throught the airbrush is much louder.

Let’s see if I can get another 30 years out of this compressor - if so, then maybe I won’t need another one…

And I firmly believe this is a lot better machine than most of the stuff you can buy when it comes to airbrush compressors.

Thanks for reading and have a nice day!

Paweł

12

Very interesting ideas from Pawel, it’s very nice of him to provide such helpful and creative information. I’m only suggesting an alternative for a very quiet, but commercially available compressor selection, at a very affordable price.

I have two of them, for two hobby locations at my home, one in the garage shop, the other in the house hobby shop for winter use when it’s cold. The first is a twin cylinder California Air Tools model, 1610A, I think it’s about a three gallon tank. Very powerful and quiet, noise level is a non issue, not much more than the human voice.

It allows continuous spraying for several minutes, then only operates for about 20 seconds to fill the air tank again. It’s about 15 years old, zero problems and has seen lots of use. It’s probably upwards of about $200 now, but is really likely a lifetime investment.

The second one is from the same company, model 1060S, even quieter and still the same efficieny. I paid $150 for it some time ago, flawless service and reliablity, I highly recommend them both, based on personal use experience.

If the homespun type will cost nearly as much by the time you source the materials and assemble it, the additional cost for the ones suggested and offering “plug and play” use might make sense for you.

Patrick