Vacuum pump from throwaway compressors?

[ChrisPer]

I want to make a vacuum pump for debubble-izing investments, vacuum pressing poster block mounts and maybe sucking 20-litre oil drums flat to impress the kids.

I know some compressors, like Root blowers, run equally well in reverse and others do not.

Has anyone here tried cutting the motor/compressor out of a fridge and using it for a vacuum pump? Or maybe a car aircon compressor with a washing machine motor?

[Hanz]

Some use a refridge pump to suck down AC systems. Mine is a little overkill, the 220V AC compressor from a home central air unit, using the suction side to suck down automotive systems.

[WLW19958]

Hey Hanz,

I agree that the electric compressors out of an old window A/C unit work great! Just don't forget to squirt a little refrigerant oil in the suction side once in a while. A new compressor used to evacuate can pull 29.5" of mercury and a good used one should be able to pull 29". Not too shabby!

Regards,
Webb

[steamin10]

Any fridge or AC unit that is still working (pumping ) is a good candidate. One recently made was converted by drilling a TINY hole in the top of the hermetic case to relieve leak pressure and screwiing the blobby thing to a piece of plywood with rubber feet and adding a houshold lite switch for the off and on...If your unit loses oil out the hole it will quickly run the unit dry and score the bore on the pump.. Bingo- you are done... These units work fairly well and have been used by enterprising guys like me to do vacuum jobs on equipment.. Dont forget the valve sets....Dave..