DIY compressor

[rogue_engraver]

I read the post on building your own silent air compressor from a refridgerator compressor. I have several questions on this. 1. How do your add oil to it? 2. Has anyone else built one?. 3. If so, how long have you used it? 3. Is it worth the effort? Thanks a Lot.

 

[monk]

did you ever oil the compressor in your refrigerator ?

 

[Tim Wells]

They have oil in them by default Monk. To answer your question they work and are quiet. I made one but didn't finish it yet. What I mean is I tested it and it works, I just haven't gotten around to making a mount for the tank and all that jazz. Too many projects.

The oil filling question I don't know the answer to. I'd ask a refridgerator repair person, IN PERSON. If you just cold call and ask something like that they may not want to help and just blow you off. Good luck and post the answer when you find out, maybe with a picture.

I found a step by step how to on the web once with photos and he never mentioned what to do about the oil...

 

[Mike Cirelli]

I would say you would use some sort of vacuum pump oil. When the pump is use in a refrigerator it's filled with refrigerant which has oil in it. When used as a compressor the oil would pump throw it with the back pressure created.
Just a guess.

 

[pappy]

some of these compressors throwout a lot of oil mist with the airs stream. you may have to add a valve to the bottom of the compressor housing and let them drain back to the compressor 1 or 2 times a day.
Rememember that refridgerator is not made for air with O2, and the thermal overload switch may have be jumped out, which is a fire hazard as the motor may get hot enought to burn with air instead of freon in the system. Please be carefull!

 

[pappy]

monk, you usually oil a refridge compressor when you change freon or open system for service. either the oil charge comes in a little can with freon with compressor oil, or for bigger systems it is in a bottle to add the right number of oz.
then you evacuate the system, recharge, leak check, and your good to go. Just be carefull!

 

[Leonardo]

Hi Rogue!

1- You should add a centrifugal air filter at the outlet as a primary filter. This unit will be getting the oil that the compressor sprays with the air. To refill you only have to inject it again at the inlet with a syringe.
2- Obviously I did it.
3- It is still running.
4- I spent about 80 euros in the new parts and the price for a new compressor is between 550 to 700 euros, so I think it worth the effort.

It was a funny project. Good luck!
Leonardo

 

[Danny C]

I also looked into this type of setup. I work for an HVAC School. So here it is in a nutshell
Oil IN the system is a must to keep the pump working (lubricated). So just hooking up a line to the OUT will get you oil, until it is exhausted, then soon after so is the pump.

There are compressors that don't need oil IN the "vapor stream", they have it in the crankcase and "oil splash" up to the moving components, like a car (and like a car, a bit gets by). These, however, are not cheep but will work.

You can use an OLD A/C compressor off of a Ford. They put out a lot of air, are self contained (oil in the bottom, not in the system's "vapor stream". This one seems to be the best bet, overall.

 

[rogue_engraver]

Hey fellows, Thanks for the input, I guess I'll spend a few days and build one. I will keep you posted.

 

[Marcus Hunt]

Just make sure you think "SAFETY" at all times because what you make has the potential to go off like a bomb! The receiver must be pressure tested and you mustn't forget a pressure release valve.

 

[Michael McGrew]

Paasche Air Compressor

I recently purchased a DW4000 "airbrush" compressor from Paasche (via eBay). The only reason I mention it in this thread is because it is a "commercial" version of what you guys are describing. It has a refridgerator compressor coupled to a 1gal tank with an automatic pressure shutoff switch. I paid less than $200.00 for it delivered. It came with a separate bottle of oil that I added to the unit via the "air breather" tube. The unit has a site-glass to monitor the oil level. Here's the problem. The unit uses ambient air to cool it, meaning there is no built in fan to force air around it. The instruction manual (all 3/4 xerox page - cut off) states that the unit is "thermally protected" and will automatically shut off if it overheats. Well, it is no louder than a fridge when running which is wonderful since I recently sold my Gravermeister ;-) I have had the unit since January and usually don't run it for more than 1 hour at a time using my Gravermax. The other night the unit made a strange "cough" sound and stopped. Ok, no biggie, may have been pushing the unit a little hard. Added an external fan to the unit, waited until the next day, turned the switch back on, heard a slight "hum" then a "poof". That was the last time it ever operated. I contacted the manufacturer and was told that it was an "airbrush" compressor and I shouldn't be using it for that purpose. Silly me, told the truth about how I was using their compressor (which by the way, works perfectly with the Gravermax). Couldn't make the guy understand that the compressor doesn't care what it's supplying air to as long as it is within the capacity of the unit. I finally got him to agree to let me ship the dead compressor (my expense of course) back to them for repair or replacement. Think I'll leave the replacement in the box once I get it and dump it on eBay. Sorry for the long "rant" but I wanted to warn those considering going through the hassle and expense of building one of these to consider the potential for overheating with this type of setup be it home-made or commercial. In fact, I was looking for recommendations from the members for a reasonably quiet, not too expensive, compressor if such an animal exists.

 

[glendikes]

Frige Compressor as air pump

Snap, Crackle, and Pop are best left in the breakfast bowl not in the air compressor. Everything that has been said is true. Cheap, fire hazard, oil blower, and many other things.... Small, fractional h.p. compressors can be made to compress ambient air. Ambient air+refrigerant oil+ condensing moisture+ heat= formation of acid in the oil. Acid desolves electrical wire insulating varnish. Electrical failure or mechanical seizing from pumping oil will most likely be the demise of your efforts. After having fought with these items in the refrigeration/HVAC trade for 30+ years, I don't think you will be happy with the results of your efforts. Just my 2 cents worth from a long life of junking!
Best Wishes,
Glen Dikes
Mission, KS and Oklahoma City, OK

 

[metalchipper]

Quietest air compressor on the market

I use a 5 horse 25 gal. compressor. I never hear it run.

It is in a detached garage in a insulated box with heat tape for winter. 50 foot airline brings the air into my house shop, I have a switch in the shop to turn it off and on.

Only problem is iceup in the short first piece of hose before the water trap on the outside of the box. Only happens a few times a winter. I just take the hose off and bring it inside to thaw out.

Hope this helps, PS Its nice to have alot of air when bead blasting ect.


double PS -- YUP using a refrigerate pump will pump any oil into your air graver gumming it up, and with out new oil the pump will wear out soon.

 

[Unkl Ian]

...and you mustn't forget a pressure release valve.

Pressure relief valve,AND pressure shut off switch.
Learned that the hard way.

The tubing I was using is rated for 300 PSI operating pressure.
One of my early tests ended with a LOUD bang.

 

[beegee]

Since the market is saturated with cheap oil-less compressors that you can buy for $50-60, I'm really curious as to why one would go to the trouble and expense to modify a refrigeration compressor? I guess if one likes to tinker it would be fun.

 

[Unkl Ian]

Many of the cheap oillesss compressors run hot,which creates condensation in the lines.
And they are noisier.

 

[Danny C]

Oil less compressors are NOISY. The reason for the refrig compressor is quiet - do you hear your fridge running?

McGrew - you should have (hindsight is 100%) put a fan on the outside that forced a lot of air passed the cyl head. It would have worked well for a much longer period of time. A larger fan that cooled more of the unit would work better. A fan shroud that directed and funneled the air passed the head, even better.

The Air-Brush units ARE too small for your work - they have to work at 100% for a very long period of time. Air-Brushes use much less air for a lot less period of time. If more is needed a larger system is bought, they run into the problem also.

If you would have run it into a $35 accessory air tank and then to the graver (with appropriate shut offs) then it would fill the tank and rest, not run continuously (as you hinted at). True some Air Brush compressors have a small tank, but these are buffer tanks to even out the pulses of the compressor. Not real storage tanks.

Just my opinion

 

[beegee]

I use an cheap oilless from Lowe's with water traps. Mine has been abused for over 12 years and still functions properly.

 

[Ozgraver]

I bought one of these little Chinese/Taiwanese oil-less compressors with receiver and regulator/filter/pressure gauge for AUD$ 79.00 (USD$73.00 at today's rate).

When working constantly with my Lindsay Palm Control, the compressor only kicks in every ten minutes or so for a few moments to top up the receiver and it's quieter than the fans in the computer sitting next to it!

I normally buy top of the line tools so they last a lifetime (and hopefully my son's too), but on this occasion I bought the compressor with the view if it only lasted for twelve months, it was still a reasonable investment. However, when it arrived it became apparent what a great piece of kit it is.

I now know two other people with the same units and one of them has been running his daily for over two years without issue.

Sometimes you don't have to spend big to get what you want.

 

[Roger B]

Say Oz, where did you pick this one up?

Roger B