A previous thread brings up something that I would love to see addressed by turners with A/C refrigerant type vacuum pumps anyone that has experience with them. Our club is in a very spirited debate about this subject and with a lot of us looking to build vacuum systems, we are split on this pump type question.
I am in construction, and see the Robinaire, Gast, Yellow Jackets and on and on used daily by the A/C guys to evacuate the lines before charging with freon. By nature, these pumps use replaceable oil that also traps and filters out the particilates that are in the gases sealed in thesystem. These pumps are used to evacuate a closed system, and they rarely "mist" oil.
However, I have been warned by my amigos that use these pumps that when the system leaks (think 5 CFM pump trying to pull 27+ lbs.) it has the tendency to mist oil. A very leaky system will cause not only for the pump to be unable to attain proper vacuum and evacuation, but will also make the pump "mist" or leak more. Sometimes a "fair amount". This "fair amount" is a whole different subject.
To further muddy the waters, I was in contact with a professional vacuum pump rebuilding company in CA and they also told me that these pumps would be unsuitable because of the misting problem. In fact, they went so far as to advise me against buying their product! They thought I should buy a true lab type vacuum with no oil bath (except for the piston)and are watching to find one for me.
But it seems some are having great success with these AC vacuums. I have only heard of the misting problem here and there, and I am wondering if it is because the AC pumps are only actually used here and there and most know better than to use them. For those using these AC vacuums, how much mist is there? I am a full time carpentry contractor, and I am here to tell you only my planer makes more damn mess than the lathe, so I am wondering if it is a matter of perspective.
Any thoughts? I can get a good 5 CFM pump with a 2 horse AC 115 volt motor of many different manufacturers delivered any where from $100 to a 6 CFM Robinair monster brand new with warranty for $250 or so (that would also do some veneering!). But they are all oil bath pump for AC. That also means that the oil needs to be changed every once in a while.
The good capacity, multi CFM lab type oiless vacuum I need to turn wormy mesquite is proving >quite< difficult to find. One of our club members has made one and his GAST is a 3/4 hp pump pulls just a little over 6 CFM. Cost? He bought the pump for $200, put a $125 dollar rebuild kit on it HIMSELF over a period of two days. Cracks, spalts, worms are no match for this pump on his OneWay. This pump new is $800, and professionally rebuilt (IF available!) is around $500. Ouch!
But I am looking for something easier than finding a suitable pump, then rebuilding it properly. I don't know how to rebuild a vacuum and would rather be turning than learning something I have no interest in. This pump will be used on my Jet mini, and my Nova 3000, so I don't see the point in buying a tiny vacuum.
All thoughts and opinions are completely welcome.
Robert