How To Make a Vacuum Pump from Old Compressor 

this was my first vacuum pump. when I started in the HVAC trade in 1979 I worked for a one man shop "Smitty's airconditioning". after about 3 months he helped me [ he did all the soldering] build one of these from a old fridge compressor. I have no idea how well it actually worked but after seeing your video I think Ill build one and see. and a dial -a-charge haven't one of those in years. cool video thanks. great job.

You sir just saved me 200 dollars. Thank you

all done on carpet - nice work

Schrader valves... the little valves that you removed to save the rubber seals are Schrader valves. (made in the USA) Good video, I have used a compressor I converted into a vacuum pump out of a freezer, for more years than I like to admit, for vac'n down AC units . Works just about as good as what Snap-on charges way too much for. (adjust the flame on your torch and watch pointing it at the compressor too, friends.) Oh and the larger the freezer or fridge you find usually has a larger compressor and it works a bit better. Sad that almost a half a million views only gets ya a thousand shared opinions. But I noticed most of the comments were just negative so maybe it's a blessing... Oh and also, if you work, walk, and lay on concrete enough, you will find some used carpet to put in your work shop or garage and always keep an eye out for some more to replace the burnt, torn, wet, oily carpet you abuse . Peace

One of the better of these videos.

This is a very interesting video, however I am much more interested in why anyone would use a large blowtorch to solder copper tubing over carpet.😆😆

It will hold a vacuum if you shut the valve on the gauge. Also, you need to hook up the ground wire in case of a short it will trip the breaker instead of getting a shock.

From my knowledge compressor oil reacts with the air, I'd recommend draining the oil from the unit and replacing it with air-compressor oil ;)

Was the compressor emptied of oil that it came with?

my problem is that the oil in the fridge motor blow out

Hello, could you please tell me what is the kind of pressure sensor you are using ? as well, what is the ultimate pressure you could reach with a compressor working as a Vacuum pump ? Thank you in advance

How many microns did it pull down to?

I'd imagine if you clean the pipe better and don't finger it all up you could use 95/5 solder and a map gas torche or even propane, also I wouldn't suggest soldering over carpet lol. I do wonder why solder the piece on the vacuum side? I was thinking of just putting a compression valve on the outlet and also a ball valve on the pull side even though I will have another valve on the gauge.

Thanks for the video. I have the same compressor but not sure where the black and white electric cables should connect?

Solder on a open flame will turn to mush really quick if left there too long. You only needed to heat the parts up first then apply the solder with large solder joints. A open flame produces soot, which you don't want mixed with solder. Of course a high wattage solder gun would have worked also if you had one, but it's a bit tricky to use on large parts with little to no experience. Good soldering takes practice... sorta like welding need that experience to get good at it.

in 12 minutes you answered all my questions. Short and to the point. Some guys have posted videos of making a vacuum pump for 30 min to one hour and it is just a waste of time watching their videos.

Great work thanks for the knowledge

Valves are called boltigen service access valves 1/4"...I just ordered 5 from amazon for $10

Where do you get those little brass valves?

Very well explain video, thank you

3rd hose is just a process tube... The guy is just having fun, lighten up people...

What's that device name? That digital pressure gauge...

To sand the stubs of tubing, turn the unit on its side, more than 90-degree turn, so the grit will not go down the tubing into the compressor. Or plug the tubing with rolled up bit of paper towel, to be removed after sanding. Just be careful not to dislodge the temporary plugs while sanding! _For better vacuum, especially for deep vacuum, pump _*_into_*_ vacuum!_ For instance: Run 2 old compressors in series, with the outlet of one into the inlet of the other. If one has larger capacity than the other, you would generally want to put it on the low-pressure side, for maximum pumping rate, but valving varies and some valves require more pressure to open than others. The one with least valve restriction at low pressure should be the one connected to the system being pumped down. Also, a proper vacuum pump can be boosted with a crap pump like a single old compressor, IF the proper pump has a vacuum fitting on the outlet. Another way to go is to pre-evacuate a large cylinder and attach it to your pump outlet after it has pumped what it can out to atmosphere. You also can increase pumping speed --and protect your pump from water damage-- by using a makeshift cryopump; that is, pumping through a U-shaped section of larger tubing you have prepared for the purpose of dunking in ice water with salt poured over the ice. Salt over ice makes the briny solution temperature drop to near zero Fahrenheit, so it can condense some water vapor even in vacuum. Better still, submerge the makeshift cryopump in a container of dry ice and alcohol, or if you can get it, use LN2 (liquid nitrogen). Copper wool (or brass wool or stainless-steel wool) inside your makeshift cryopump will improve the performance by adding a large surface area on which the pumped molecules can slow, contract, and even solidify. Purging the whole system with *very dry CO2* will allow you to turn a crude vacuum into a high vacuum if the cryopump is chilled with LN2, because the CO2 will solidify on contact with such low-temperature surfaces. Other gas molecules being carried along by the CO2 will get buried and trapped in the dry ice formed in the LN2-cooled cryopump. Normal refrigerants will also solidify in a LN2-cooled cryopump. With proper valves installed and operated, you can make a laboratory-grade vacuum in a cheap way. After using the cryopump, be sure to warm it up and pump it out with your regular pump, to dry it thoroughly. As always, higher temperatures of the system being pumped will speed the process of evacuation. Water is particularly sensitive to temperature and will basically not pump at all near 32 F (0 C) unless the vacuum is prolonged and very deep.

Next video - how to replace f'd up carpet . . .

Can it get it down below 500 microns though? Preferably 350?

great video!

So many complaints! Thanks for posting.

Beware!!!! While working in the "80's" in western oklahoma some of fellow tradesmen were using old refrigerator compressor to evacuate some refrigeration systems on grocery stores. I had just been out there and I myself had used one of these compressors to evacuate a system. When I got back to Tulsa a few days latter my service manager come to me and says " do you still use a frigidare copressor to evacuate systems (sp) on your truck" I said Yes. He said take off and don't use it anymore. He said one of the servicemen called the office to say that he had one on a system and was evacuating it . He went back into the grocery store and several minutes (maybe a hour) he heard and explosion. when got to the machine room the compressor , made of 3/8 steel had blew its top off and exited the top of the machine room. what the decided happened was the discharge line may (or may not) had gotten bump or kinked and the pressure got high enough to set the oil off in and explosive bang. Just like in a diesel engine that diesel oil and a spark (doesn't need a spark if pressure is high enough) Just giving you a warning I have never used one since. Oil, Air (oxygen), under pressure do not mix Drb

How much vacuum did it pulled

Do this guy play with fire on a carpet floor?... HAHAHAHA BTW Good JOB

i have done mine also but not as thorough as yours..thank a lot for the info

Careful now! Don't catch the carpet on fire : )

Thats neat. Have you used it as a recovery machine?

too much time to solder only 1/4 copper pipe?!

Eh that compressor vacuum that he made is good enough for an old residential refrigerator if you're a tech on a budget IMO. Better "Some" vacuum than "No" vacuum IMO lol ...not a lot of people can afford a $600 vacuum.

What the valve on the pressure side for?

I think you should put something over the carpet, you know like tarp or even some ceramic tiles over it... you don't want to set that carpet on fire.

If a compressor reaching 300 stedayonly it can pull 700 hygrade or 450 Micronesia .

This is a great video. I enjoyed it. Thanks for making it. I have my eye open for a compressor in good shape. That is some really nice carpet to be doing such work, though!

my knee's are hurting watching him.

Hi Blade very good video! Thanks I have a question..... when you wire the power cord to the compressor you did NOT wire the green cable from the power cord.... which we all know is "earth"... sooo if we wire our pumps like this is may be a dangerous from electric shock when we touch the compressor metal body ? Or maybe im wrong!?

It is not a magic. The vacuum pump is essentially a compressor with some gadgets added. It depends on refrigerant, but you can end with very hydroscopic oil, and most refrigeration oils are. Refrigeration oil turn acidic when get moisture, and acid will kill copper winding. I would definitely change your oil to a vacuum pump oil. Also I would add drain on the bottom to replace oil in the future. You can build a very good fluid extractor using free fridge compressor as a source of very strong vacuum. I would use refrigeration filter/dryer to protect compressor/oil from moisture.

Refrigeration compressors are low volume, for faster vacuum use an AC compressor for an old windows AC. drain the oil into a container before soldering, then add it back In. I'd put a suction line filter neutralizer on the suction side to protect the compressor.

Where did you get the pipes and fittings from?

I didn't know those compressors also made really good vacuum pumps.... thanks for the video.

mY wife slap me to next tuesday if I did any thing like this on HER carpet ! LOL

Could you please tell me where do you find these brass fittings to fit those hoses to solder on with

what to look for when buying used fridge compressor? which brands last longest and pump out more air?

What is the size of these valves?

It also works as air pump

Tell us more about the valves please. I've seen that kind of valve on a bicycle inner tube... but not anywhere else... and never with a "big" length of copper pipe attached. What kind of valves are these? What are they "really" for?

please tell me the name of the correct valve connector, i need a vacuum pump to evakuate my car A/C System which connector do i need?

Remember folks this guy is a Pro? Don't do this at home....He had at least 4 major safety problems the least of which soldering on a carpet good way to burn a home down

could some one please tell me what was the final pressure in mBar

What's the Ultimate Vacuum in micron ?

What size are the Threads in the valves?

To youdsehst you should do another video on your content. Writing s book here is too much man.

The green wire should Really be connected to the body of the compressor for safety

This is very heavy can you make small and light weight 🙏🙏🙏

Enjoyed the video. Still a mystery which tube goes to pull vacuum and which is output (and which sealed off)

How many hp of compressor

where did you get the valve? what size or some information how to get the good one. Thanks for the video

What unit is 24.7 ?

Thanks got a general idea. 👍 I'll definitely get a work bench first, lol

Remember to do this on a carpet. For best results buy a new carpet.

This seems to be more of a recovery pump than a vacuum pump. It could be used as a vacuum pump with some type of check valve/ oil chamber on the outlet side. I definitely like the idea tho because without the chamber your able to use it to recover with you can pull a vacuum.

Hope you cleaned up the motel hallway carpet after the video. It really is the best place for soldering copper.

How can I tell which line is the vacuum or the high pressure? I have a compressor that isn't cooling. Don't know if it's freon related or some other problem. The compressor sounds like it's running but doesn't get cold.

schrader valve..in the port

That is special teflon fire insulate mat. Not carpet.

If i use the vacuum port to vacuum smoke that will be bad to the motor considering that the motor working with oil?

I think we need more heat!!!!

Did anyone ever tell you that you sound like Trey Gowdy by the way that's a compliment😉

Thanks man... plenty good for a vacuum press pump I reckon and probably as good as the real thing.

As a refrigeration expert - This is very misleading information. First - A real vac pump does not look like what he shows - look for yellow jacket or appion Tez 8 (dual piston). Second this compressor will run a few hours then die because no oil is recirculating back through the suction and moisture in the air will turn the oil acidic and eat away the windings quickly. Third As others have mentioned the industry standard micron level is 400 or less (basicly a compressor cannot pull a deep enough vacuum to ensure a quality job on refrigeration). When you are dealing with zoetrope (400 series) refrigerants this is EXTREMELY important.

Hello does using a large heat sink or fan prevent compressor overheating ?

Why would anyone do work like this on a living room carpet without protecting it from melted flux, dripping solder, hot torch tips and such? A workbench is the normal/sane way to do this work.

great recycle of the ubiquitous CL "free working rusty fridge" for something slightly more productive than beer chilling!! why use hard solder though? even a perfect vacuum is only a bit under 16 psi, and the pressure influence would tend to make your swaged fit tighter. plain old 50/50 you can get away with a cheapo propane torch rather than needing a more sophisticated air/gas rig. the refrigerator needs hard solder because it's a couple hundred psi differential, and it's trying to make stuff fly away from the "source" (your comp head). i know for you it's an a/c refrigeration tool, but it's a handy puppy for lots of other stuff too (like laying fiberglass, de-airing thick gooey mixtures, or collapsing 55 gallon drums, lol). also that inch and a half of 15% silver costs about 10 times what the same length of 50/50 does. good vid though, nice and to the point, not a lot of wasted time watching you do uninteresting stuff, lol. what oil do you run in it? 24 3/4 inches is pretty damned respectable, btw! think a "flap valve" on the outlet could buy you another inch or 2? hell, a ping pong ball behind a cross pin that gives a little "wiggle room" would probably work (and a ball valve for your "sealing cut-off", lol. no cap and plier juggling then). i know, "make your own damned vid, know it all!!!"... lol. sorry about that, just "fresh eye product and process improvements" ideas.

Use what you got handy or what’s available. 🤘🏼

what micron show on gauge?

Thank you for the information, I am very interested in making it. I like to send packages and subscribe, I wait for the reply to be ok🙏👍

What kind of valves? Check valves? How do you know what's the inlet and the outlet? If you are using check valves why do you need to cap the output to hold the vacuum? It looks like your valves aren't actually doing anything and you could just use any fitting.

I hope your wife doesn’t mind burn holes in the carpet!!😮

This video shows how to solder Schroeder valve fittings on old refrigerator compressor. Wiring (???). Lubrication ( ???) will it run for an hour dehydrating auto air conditioning system (???)

What is the measure of those valves?

where can I get those valves please?

Great video. Thanks

Ok but, what is the vacuum pressure you got? 241 what?

first chinchilla thought of was the carpet, second was pointing the torch at the compressor. There is something wrong with me. Dude, nice build, seriously.

I just removed the air compressor from my freezer and wired it up with a Supco 3 n' 1. The air compressor hums quietly (almost silent) but very little air is coming out of the outlet. What's up?

Refillable butane torch would be so much more precise & manageable - that oxy rig is like going after gnat with a locomotive.

I think this guy means well but this compressor will never pull 500 microns so it can’t be used as a refrigeration vacuum pump

MAKE SURE GUYS DO THIS ON THE CARPET OF YOU LIVING ROOM OK IF NOT DON WORK

How did you know which side would be the suction side?

So you only need a valve on the suction side...

Great video!!

i couldn't quite make out what u said so can u say again, what those valves were called please bud?

Does go down to 30 hg vacuum?

have you ever checked what is CFM of this kind of vacuum pump, or anyone? thanks

-200 psi or bar ?