Does vacuum pump oil pose a fire hazard?

[Richard Dooling]

I have been reading about DIY approaches to isolating the oil mist produced by a common HVAC type vacuum pump. Most of the DIY ideas involve piping the oil into some sort of container or filter filled with a medium that the oil would condense around or be absorbed into.

If the medium were paper for instance, could vacuum pump oil spontaneously combust? Does his type of oil oxidize and create heat?

Thanks

[roger wiegand]

Vacuum pump oil is a fully saturated mineral (petroleum) type oil. It doesn't react with other oil molecules the way the molecules unsaturated oils like linseed oil do when they polymerize and dry. It's basically the same as motor oil. So, no, it won't spontaneously combust. It is still flammable though, albeit with a quite high flash point. Paper filter elements will quickly clog though, so probably not a good idea. Most pumps we used in the lab had filters that used a stainless steel wool in a canister that drained back into the pump. Even high end filters aren't perfect, I'd vent it to outdoors if at all possible, just attach a hose on the output side and run it through a small hole in the wall

[Richard Coers]

You are over thinking it Richard. Linseed oils are the oil to watch out for. Who would want a curing oil in a vacuum pump?

[Richard Dooling]

Thank you Roger. This is what I thought but some of what I have read on the internet was somewhat ambiguous. I appreciate the clarification.

Vacuum pump oil is a fully saturated mineral (petroleum) type oil. It doesn't react with other oil molecules the way the molecules unsaturated oils like linseed oil do when they polymerize and dry. It's basically the same as motor oil. So, no, it won't spontaneously combust. It is still flammable though, albeit with a quite high flash point. Paper filter elements will quickly clog though, so probably not a good idea. Most pumps we used in the lab had filters that used a stainless steel wool in a canister that drained back into the pump. Even high end filters aren't perfect, I'd vent it to outdoors if at all possible, just attach a hose on the output side and run it through a small hole in the wall

[Richard Dooling]

Richard, I knew about linseed oil and knew that pump oil isn't as dangerous. I wanted to be sure of what precautions are prudent for this particular oil. Given the high stakes, I erred on the side of safety.
Over thinking it? I feel that the little bit of my time is worth a greater degree of certainty. But thanks for your input.

You are over thinking it Richard. Linseed oils are the oil to watch out for. Who would want a curing oil in a vacuum pump?

[Richard Coers]

Richard, I knew about linseed oil and knew that pump oil isn't as dangerous. I wanted to be sure of what precautions are prudent for this particular oil. Given the high stakes, I erred on the side of safety.
Over thinking it? I feel that the little bit of my time is worth a greater degree of certainty. But thanks for your input.

If you want certainty, a quick search for vacuum pump oil and reading the cautions and warnings on the SDS sheet would provide all the exact data directly from the manufacturer.

[Allan Dozier]

Roger nailed it as far as spontaneous combustion. It is the oxygen that is the offender as I understand it with drying oils and varnish. Since this is in the turning forum I assume you are using it for a vacuum chuck. If you are using it in HVAC work to evacuate lines then you don't want to use any method that reuses the oil since it contains some of the moisture you are trying to get rid of. Always replace the oil with fresh if using for HVAC.

[Kevin Jenness]

You can avoid the issue by using an oil-free pump like the commonly seen Gast rotary vane units.

[Mike Henderson]

You can avoid the issue by using an oil-free pump like the commonly seen Gast rotary vane units.

This^^^ Most of the oil bath vacuum pumps are intended for air conditioning service where they have to pull a high vacuum to get all the moisture and air out of the lines. You don't need that for most woodworking work. An oil free pump (like a Gast) will work fine for veneer or vacuum chuck work.

Mike

[Richard Dooling]

Richard, thanks and yes I should have read the SDS. It's obvious but I just don't think of that. I just immediately jumped into the WWW universe of unverified information.
I did find this yesterday though:https://www.newpig.com/absorbent-tra.../8036?show=All

Kevin and Mike, I would prefer to have a Gast or other oilless pump but it's not in the budget right now. I had the HVAC pump so went with that but I didn't realize how must oil mist those things produce. I'll probably get a pump from Frugal when I recover from having to have my roof replaced.
http://www.frugalvacuumchuck.com/home.html

I have to admit that the vacuum chuck is much more useful than I thought it would be!

[Kevin Jenness]

I have to admit that the vacuum chuck is much more useful than I thought it would be!

Vacuum chucks demonstrate the awesome power of nothing.