Vacuum pump oil info needed!

**smoke** · 06-01-2012, 10:04 AM

Someone please clarify something for me.

I have always had the understanding that vacuum pump oil was a specific type of oil. That is why we purchase it at our supply house instead of any automotive store.

I thought vacuum pump oil was hygroscopic in nature (absorbs moisture) and this being the reason that keeping fresh vacuum pump oil in your pump will aid in quicker pull downs.

I have someone stating they have compressor oil of the same viscosity as vacuum pump oil and I should use it in place of true vacuum pump oil.

Can someone please clarify this for me? Reference material (website links or references) would be awesome.

Thank you to those that can help me!

~smoke~

**Chuck** · 06-01-2012, 10:13 AM

I have always used real vac pump oil.

I was under the impression that vac pump oil has a lower vapor pressure than compressor oil, and allows the pump to pull deeper. I don't know if this is true or not.

I am looking forward to the answers too.

**Chuck** · 06-01-2012, 10:26 AM

Originally Posted by FeSantacl

nothing else needs

???

**smoke** · 06-01-2012, 10:27 AM

I am in a location in a part of the world where I cannot go down to Johnstone Supply and pick up a quart of vacuum pump oil.

This is someone's idea of a temporary fix but I'm not convinced. I am also not a chemist. I am searching the internet for facts but haven't found any yet.

I'm sure someone on here has the information.

~smoke~

**hotrodrob** · 06-01-2012, 01:38 PM

good question, here's what i got from JB's website.

2. Why is it so important to change the oil often in my vacuum pump?
The proper oil in a vacuum pump acts as a blotter and absorbs all of the moisture and non-condensables. As the oil becomes saturated with these contaminants, the efficiency of the pump is dramatically reduced. Maintaining clean oil in the pump ensures that the pump will operate at peak efficiency.

--------------------------------------------------------------------------------

3. Can I use any oil in my vacuum pump?
No. JB Black Gold oil is extremely pure and non-detergent. Black Gold is hydro processed which means it goes through a series of catalytic steps rendering the oil extremely refined, more viscous, and more stable. The result is a clear mineral oil that will alert you to contamination sooner as it becomes cloudy or milky.

**smoke** · 06-01-2012, 02:52 PM

Thanks hotrodrob!

I figured that vacuum pump oil was a more refined mineral oil but will it hurt the pump to run compressor mineral oil?

Any additional input is greatly appreciated!

I am at a remote site, 8,000 miles off the east coast of the US. Going to bed now. Anxiously dreaming about responses in the morning!

I have 3 pumps here, I can always try it with my least favorite pump and see how it pulls down the microns and to see if it catches on fire...

Thanks all!

~smoke~

**hvacker** · 06-01-2012, 03:19 PM

I have used compressor mineral oil in vacuum pumps in a pinch w/o problems I know of. I think the oils have more similarities than differences but true information is scarce. A compressor is a pump also. The most important thing is that they remain lubricated. Being a long way from home sometimes one has to be creative.
Don't use anything meant for internal combustion engines. They contain additives not meant for vac pumps, like zinc.

**MicahWes** · 06-01-2012, 07:21 PM

It is just mineral oil.

**mikep** · 06-01-2012, 08:40 PM

As I recall vacuum pump oil has a boiling point much higher than compressor oil. I believe that vacuum oil is also called "top cut", meaning all the lower boiling point portions of the oil have been remove. This makes it capable of pulling low vacuum and not vaporize off while doing so.

**Chuck** · 06-01-2012, 08:47 PM

Here are MSDS sheets for;

Nucalgon C3 Mineral oil, Vapor pressure <.001 mmHg
Nucalgon Vacuum pump oil, Vapor pressure <.0001 mmHg
Yellow Jacket Vacuum pump oil Vapor pressure <.01 mmHg

The vapor pressure for Nu Calgon mineral oil is lower than the Yellow Jacket vacuum pump oil! So you could technically pull a deeper vacuum with Nu Calgon mineral oil than with Yellow Jacket vac pump oil.

The Nu Calgon Vacuum pump oil is the lowest which makes it an excellent choice.

Smoke, I'm guessing you would not notice any difference in pump performance by using mineral oil. You could always connect your micron gauge alone to the pump and see how deep it pulls.