Ive found an old bar fridge on the side of the road and am keen to use the compressor as a vac pump.
firstly, any advice removing it from the fridge would be appreciated. what to cut and not cut, etc.
secondly, ive plugged the fridge in and it works. if it doesnt get cold after a while, can i assume that the freon is exhausted and its safe to use without being taken to a freon recycler? if not, …?
thirdly, i know people have all kinds of switches and relays, but can i use this compressor straight up without getting tricky with those extra bits?
ive also read on the net that some fridges and freezers have capacitators (not sure if thats the right word) that store electricity in them even when the fridge is unplugged? should i be worrying about that before i start hacking it apart?
Here the rubbish dump has a degassing service, so you can degass and extract the pump then dispose of the fridge at the same time.
I’m not a tradey, but capacitors discharge naturally over time. If it’s been unplugged for more than a few hours you should be in the clear. It’s not easy to store electricity for long periods of time without chemicals (batteries).
Earth all the connections briefly with a wire if you’re worried.
Fridge pumps are great, the best low-budget option! They work hard, especially if you’ve got one of the old “pancake” ones, that look like a cough drop. Often made in Italy
A vac switch will greatly improve things, but you can run them constantly with a pressure bleed-off, as long as you keep the oil topped up and point a fan at it to keep it cool
You really do have make sure they remain cool and lubricated. It is worth taking the time to do the “tricky” bits with regards to:
cooling, proper fan ventilation, in some cases attaching cooling vanes may be a good idea
safe electrics, sealed connections and a good fuse box
Clean cutting of tubes with a set of cutters not a saw, avoid particles entering the pump or oil as they can lead to friction, blockage and general wear and tear.
Proper disposal of gases, for safety and environment as well as compliance with laws.
exhaust and intake filters, first one to control oil spillage and vapour, the second to preserve the pump and oil longevity.
Timer or switch to make sure your pump never runs more than it should and that in the event you cannot make it back onsite on time the pump doesn’t contine unchecked. I use a timer to stop the pump when the resin has set.
Alternately, nowadays there are inexpensive pumps for sale on ebay and the likes, the typical membrane pump is sufficient for most hobby compsand projects and I currenty have one that I use for snowboards which I got off ebay for 140 euro: It has a manometer and vapour filter all fit and ready to go.
I’m with Kit on this. I love fridge vac pumps. I’ve got an old lozenge shaped one that I’ve probably used on 20 boards. It’s simple - no switch just a bleeder valve on the vacuum intake and a vacuum gauge. Been topping up the oil with regular car motor oil. The vac exhaust gets run through a vinyl tube elevated about 2m into a plastic collection bottle which I put back into the pump. Learned most of this from the model plane builders.
I’ve got a propper vac pump but the thing is so damn noisy I’ll stick with the fridge pump til it dies-it’s so quiet I have to really listen to figure if it’s going. My local dump used to sell fridge compressors with the freon already out for $3. Now they send all our waste to Aukland and the dump store is closed - thanks to the wankers on the district council. I’ve used some of the more modern fridge compressors and they’re kind of tempermental - they cut out when they get too hot. The lozenge shaped one cuts out too but it’s got to get uber hot.
One time I was out doing something and asked my wife to keep an eye on a vac job in mid summer. It’s not exactly desert here but still… Recipe for disaster I know. But she wrapped the compressor in a wet towell and it came out sweet. Been doing it ever since and put a fan on it as well. I usually re-wet the towell after about 3 hours which is usually bed time. Never had the pump cut out with this method. Hope this helps.
its council clean up this weekend so there is an assortment of junk lining the streets. today alone ive spotted about 6 fridges within a few hundred metres of my house, so i thought it would be the best time to start getting a vac pump going. the bonus is that once ive removed the pump i can put the fridge carcass back on the street for collection on the weekend.
i picked the oldest fridge i could find after reading that the newer compressors overheat easier and dont last as long.
i dont think the one i got was a cough drop, although it is made in italy. ill keep my eye out for one of those tomorrow.
thanks dave, there is heaps of info about switches and relays and stuff on here, but i want something ultra simple to start with. im going to stick with a fridge pump to for now. 140 euros is about 140 times my budget for this baby. i will definietly take your advice on cutting the tubes cleanly.
Keep an eye out for those drink coolers that take the big bottles of water as they have a nice little pump in em. I got mine for 10 bucks from the local junkshop. I just run it constant with a bleeder and a fan. to easy.
Ive got the pump out now, it definitely worked when it was in the fridge but now it doesnt.
i read another post about a similar problem, again with your advice I had to cut the cord that goes from the compressor into the fridge. the cord from the wall to the compressor is fine.
i couldnt figure out what wirse i would need to re-route. im a novice with electricals.
ive attached a picture. maybe you can offer some advice?
the power cord (the one you plug in) has 3 wires - light green, brown and light blue.
the other cord (that i cut) also has 3 wires - dark green, brown and light blue.
That wire you cut is probably for a fan or a light?
Green/yellow = Earth
Blue = Phase
Brown = Live
The green/yellow wires should both be contected together - the metal connector should be one piece of metal, so they are essentially connected to the same place.
I’ll have to take an educated guess here, as I can’t see the whole thing in person
The Brown wires are probably connected together as well - their metal contact is one piece as well?
If this is the case, then the problem you have is with the blue wire being cut
I can see another blue wire coming from that contact, second from the right?
Where does that go?
I have a feeling it might be involved
Just make sure whenever you switch the thing on that you are only ever touching the switch at the wall, and nothin else.
the wires that you cut are probably from the temp overload or door switch (or both). if you join the brown and blue together from that one it should work, or better yet connect them to a switch.
That was the case with my one.
If you know a sparky its probably better to get them to look at it or take it to a electrical repairer.
