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[Favorite tips] Vacuum pump oil


Hello All!

We have left this thread out of our stream of communications.
This was (is) a valuable thread to keep alive. Let’s try and
keep some fresh, helpful, time saving, improving quality, and
suppliers, coming along on this thread.

Too start this thread anew I would offer the following tip. If
you save your egg cartons you can use them for________ just

Just changed my vacuum pump oil last weekend. We historically
don’t do this often enough. I try to change it when I figure
I’ve got 10 to 15 hours of run time. The tip is the oil I use
comes in a gallon can, and is less than $3 per gallon. A bit
hard to find, but just 10 weight non-detergent oil! I was
dropping by Grainger’s occasionally for a $5 quart of vacuum
pump oil! Quite a difference in price. Some of you may remember
Goldspells casting- Steve Pearson. I need to credit him with
this tip. His method of cleaning, after draining the old oil,
was to add kerosene to fill level, operate 5 minutes, and
repeat. Continue process until the kerosene is fairly clean.
Then refill with 10 weight non-detergent oil. Make sure you
order non-detergent. The product I found is a Union 76 product,
UNAX AW 32. Auto parts stores don’t carry it, but could order.
It’s easier to just look in the phone book under
Oils-lubricating, to find your gallon.

Favorite tips is alive and well!


Just a quick comment on your “tip” for cleaning your vacuum
pump. I will leave my work signature on this one. We run
somewhere between 10 and 15 vacuum pumps 24 hours a day, 365 days
a year. They get serviced regularly and for us this basically
involves drain out the old oil, refill with new, replace oil mist
filters on a regular basis and have the motors, vanes and
bearings replaced whenever things start to get a bit ropey.
Granted our useage is a bit different to yours, but none of our
service personnel ever run a pump full of solvent between oil
changes. I’m not sure I’d recommend it. We have several pumps
which have been running in this way for up to 15 years.


Dr Alex Ball
Electron Microscope Unit
The Natural History Museum
Cromwell Road
London SW7 9BD

Tel 0207 942 5263
Fax 0207 942 5811

For general museum enquiries call 0207 942 5000


If you: 1) valve off the vacum line and 2) open up the gas ballast
on the pump while leaving the pump run you will help to keep the
oil purged of moisture and contaiminents. this gives a longer
life and faster pump down.

Also it is possible to reseat the vanes in the pump by an
extended run time (a day or so) with an oil change before and

To get the max pumping from a vacum pump use the largest fitting
on the pump, the shortest and straightest piping, and use either
metal piping or vacum rated hoses.

there should be alot of info in the archives as there was a
thread several months ago.


Hello Alex! Your post was quite brief! You didn’t offer a method
to clean between vacuum pump oil changes. Could it be that you
change your oil so frequently your able to ignore a thorough

Steve P. last time I was in his shop, had four Busch rotary vane
vacuum pumps, two steam dewaxers, and more kilns and gizmos than
I could count. His recommendation came when I was loosing
pressure with my pump and had already replaced the fittings and
tubing system for my system (wasted labor hours). He first
suggested that I step up to the plate and purchase a quality
pump. Couldn’t afford it then.

He then told me to clean with kerosene, and repeat till it till
it ran clean. I must have ran it through 6 cycles. Then filled
with non-detergent 10# oil as stated.

I’ve known Steve since the early 70’s there isn’t a chance he’d
stear me wrong.

My motor ( Dayton 1/3hp, 3cfm refrigeration unit) at that time
was abused and neglected. The motor was purchased with a casting
setup in about 1986.

My method for cleaning and operating is still the same. I cast,
until recently 3 or 4 flasks a week.



Just a thought. How often do you change the oil in your car?
Why not set up a schedule much like the auto maintenance.
change the oil after every X number of hours use or just every so
many days? Vac pump can’t be all that expensive if all you are
really using is non detergent 10 weight. I know jewelers are a
"frugal" lot but …(grin) Mike