How often do you change your vacuum oil?

I know a lot of people say to change your oil every time but the past few times i’ve gone to change my oil it looks just as good as the stuff going in. I use inland 19 with an e28 pump on a 2L setup so I just dont think I have the volume of volatiles coming through to the pump that some other people may have running larger setups. I use liquid N2 and ethanol to build my traps and it seems efficient enough that Ive never seen any condensation on my second trap. Right now I’ll still swap the oil out every 5 runs or so but Im wondering if this is wasteful as I look at the used oil coming out and it looks just as good as fresh inland19. is this how your used oil looks coming out?

After every run. Vac pump oil is cheap. Vacuum pumps are expensive.

Hows the smell? Terp-oil, burnt, good?

You’re really making me think about tossing those bulk masks I got up on Craigslist or Facebook market place while the getting is good


Im smelling them side by side and they smell as identical as they look. Ive seen what used oil looks like coming out of the pump and it just doesnt look contaminated in any way. Im not concerned about the cost really but I just dont want to generate as much waste because what were setting aside looks the same as new oil.

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Those are quality cold traps with a quality rated for chemical vapour pump. My set up is similar and for chemical synthesis and drying use I change it once a month. Distillation of terpenes every 2 weeks and distillation of cannabinoids once a month. I was using a 10 year old Edwards and it’s still going strong. Off topic but perhaps useful; using Edwards oil with their pumps improved my vacuum by 1 mbar compared to generic oil. Guess oil qualities differ.

Actually just swapped again and picked up a little terp smell but can you tell which is new and which is old?

With certain pumps you can lock off the inlet and run them for a while and it will outgass and extend the life of the oil.

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like blank it off and run open ballast?

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I was told the oil matters because of the nature of rotary vane pumps. The rotary vane is essentially a spinning propeller that spins thousands of an inch apart from the outter steel wall and between this gap your oil resides to ensure complete vacuum. Different oils have different viscosities which means they will perform differently within this gap. Makes sense the oil designed for their pump would perform better. Hope that makes sense !


If I don’t change every run on e2m30 it’s noticeable.


I never do 2 2nd passes with the same oil and run dual -90c cold traps. Its cheaper than downtime, high vac levels and rebuilds


That makes sense! Thanks for the intel!

On one of my older hand-me-downs I replaced the vanes and could get away with the generic oil, but without replacing the vanes, 100% required Edwards brand. But I’m all for the added cost with new vanes, keep that stuff running sharp :ok_hand:

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The proof of the pudding is in the eating of it… Is the vacuum depth any different after changing the oil?

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does it suck better when lubed correctly?

do you really need to ask?!?