Re: [APML]: Marvac vacum-pump

[Brad Wallis <wallis@pepe.jpl.nasa.gov>]

        Does your Marvac R-10 vacum pump (Lumicon 300 kit)make a gurgling
        sound when it's at max vacum?? Mine does.....and I think that this 
        is incorrect. It's supposed to make a rapping sound. I have tried
        to change oil (syntecial motor oil) but with no results. 
        Have any of you experienced anything like this???
 
 ...............

Typically these single stage pumps do make a gurgling sound when they get
semi-close to  their 'ultimate vacuum' ( when they have to WORK to pull
out anything ... )

you SHOULD be using a vacuum pump oil ... not any motor oil ...
you can get the oil from varian or VWR or a number of places...
its about $ 20 a quart ....  it has a low vapor pressure and 
will not backflow like a car motor oil will ....

if you used regular oil in your pump that may be a major problem...
I'd put in good oil right away and not run it until you do ...

Brad Wallis