Vacuum pump oil?

[Hugh]

Hi there Everyone,
I have a Gast vacuum pump that has a small jar with a wick in it to oil the pump. I filled the small jar with oil when I set the whole thing up and can not remember what type of oil I am to use. The label calls for "Gast" oil. But I remember there was a common type of oil I used. I am sure there is someone out there who can tell me what kind of oil to use.
Thanks.
Hugh😀😀

 

[Bill Boehme]

It doesn't cost much to get it from a Gast supplier or possibly direct from Gast.

This is sort of irrelevant since you already have an oiled type rotary vane vacuum pump, but for the benefit of anyone who has not yet set up a vacuum system, I have read a lot of recommendations on the various woodturning forums that it is better to use the dry type rotary vane vacuum pump. The main reason is that ultra fine dust that makes it through the inline filter from the chuck will mix with the oil and become the equivalent of a fine polishing compound over time. This means that more frequent cleaning maintenance is probably necessary to clean out the sludge and also replace worn vanes. I don't know how significant this issue might be in the real world.

 

[Mike Brazeau]

I saved a copy of a posting to "Hugh" a few years ago and this is what it said.
"As for oil Gast part #AD220, you can also use detergent type automotive engine oils with classification SF or CC usally printed on the side of the container 30wt below100 degrees F and 20wt above 100 degrees F." I have the same pump. I think they date back to the 60's when I started in the laboratory supply business. Sold them as vacuum filtration units and air sampling vacuum sources. Still works great and I have never topped up so that the wick is in the oil. Every once in a while I tip the pump over so the wick is wetted with oil. Bought it in 2001 and use infrequently.

 

[Hugh]

Thanks for keeping that posting or finding it Mike. I knew it had been brought up earlier - just did not know when and such. Got lazy and thought I would ask again. I use my vacuum 5-6 times a year when I do the bottom of salad bowls. The rest of the time I fake it. But the wick is always in the oil. So far no problems. Thanks.
Hugh 😀😀😀

 

[ihmserv]

hugh
I usually just run down to the local napa store and pick up a quart when I need some.
here's a link to napa site that shows three that they sell, all are fine for the pumps that we use.

http://www.napaonline.com/Search/Results.aspx?Ntt=vacume pump oil&Ntk=Keyword&Nty=1&N=0

hope this helps
IAN

 

[Bill Boehme]

hugh
I usually just run down to the local napa store and pick up a quart when I need some.
here's a link to napa site that shows three that they sell, all are fine for the pumps that we use.

http://www.napaonline.com/Search/Results.aspx?Ntt=vacume%20pump%20oil&Ntk=Keyword&Nty=1&N=0

hope this helps
IAN

That is not the right type of oil for this application. Your search is showing the type of oil used in piston type vacuum pumps used to pull hard vacuums on refrigeration systems.

It appears to also be very similar to, if not exactly the same thing as, the oil used in auto air conditioner compressors because it scavenges moisture from the system and mixes with the refrigerant as a fine mist as it circulates through the system. Rotary vane pumps move large air volumes at moderate vacuum levels as opposed to a low volume of refrigerant gas and able to reach a hard vacuum. The oil in rotary vane pumps needs to stay inside the pump.

 

[Mark Mandell]

Not fer nuthin', but my 6 cfm Robinair vac uses straight mineral oil. True, it is designed to pull hard vacuum on HVAC lines, so I had to fit it with a coalescing filter on the exhaust. Pulls 28" on my Stubby's internal port system, and will pull very close to 30" plugged.

FWIF, I don't use any regular oil in any pump situation because of the carbonizing effect. If you can get a synthetic in the right weight, I would use that over others.

 

[Bill Boehme]

.... FWIF, I don't use any regular oil in any pump situation because of the carbonizing effect. If you can get a synthetic in the right weight, I would use that over others.

Synthetic is fine, but I believe that the "carbonizing" that you mentioned is referenced to what happens in internal combustion engines.

Unless there is a lot of oil leakage due to excessively worn piston rings or worn exhaust valve guides allowing burned deposits on the exhaust valve seats and cylinder heads (where temperatures can be between 1000° F and 1600° F)*, the typical deposits and sludge in oil are not from high temperature burning, but rather from accumulation of acids, metals, and other nastiness that are the byproducts of gasoline combustion. Most internal combustion engines use detergent oil, which means that the byproducts are kept in suspension in the oil until it is no longer able to do so. After that, nasty sludge deposits accumulate. Most synthetic oils are also detergent and will have the same issue with these combustion byproducts.

* Most of the carbon deposits on cylinder heads is not from burned oil, but from incomplete combustion of gasoline when it is not at the stoichiometric ratio for oxygen to gasoline (14.7 to 1, if I remember correctly) to have complete combustion. BTW, at the stoichiometric ratio, the combustion temperature is 1600° F. The gasses in the exhaust manifold run about 800° F to 1000° F. Back in the "good old days" of leaded gas, engines used to be set somewhat rich to minimize detonation (the cause of knocking and pinging). The other ingredient that minimized detonation was tetra-ethyl lead. Nowadays with emission standards and mileage requirements, engines try to run right at the stoichiometric mixture or even somewhat over-lean.
​

 

[bonsaipeter]

Coalescing Filter

Not fer nuthin', but my 6 cfm Robinair vac uses straight mineral oil. True, it is designed to pull hard vacuum on HVAC lines, so I had to fit it with a coalescing filter on the exhaust. Pulls 28" on my Stubby's internal port system, and will pull very close to 30" plugged.

FWIF, I don't use any regular oil in any pump situation because of the carbonizing effect. If you can get a synthetic in the right weight, I would use that over others.

Mark Mandell mentioned he fitted a coalescing filter onto the exhaust side of his Robinair vacuum pump. I too have a Robinair vacuum pump and I'm bothered by the odor of the oil vapor that comes out of it, especially after it has been running for a while and the oil heats up a bit. Mark, can you tell me some more information about the coalescing filter you installed, make, model, and possibly where to obtain one? Did you also have an unpleasant odor issue and did this filter help? Look forward to your response.

Peter Toch

 

[Mark Mandell]

Mark Mandell mentioned he fitted a coalescing filter onto the exhaust side of his Robinair vacuum pump. I too have a Robinair vacuum pump and I'm bothered by the odor of the oil vapor that comes out of it, especially after it has been running for a while and the oil heats up a bit. Mark, can you tell me some more information about the coalescing filter you installed, make, model, and possibly where to obtain one? Did you also have an unpleasant odor issue and did this filter help? Look forward to your response.

Peter Toch

Hi Peter,

This will take a bit of plumbing because the exhaust on the Robinair is through the handle. Fortunately, the exhaust "port" is just the right size to carefully tap with a 1/2" pipe tap. Once that is done, a couple of copper fittings and a brace and you can "hang" a coalescing filter off the rear end of the unit that will catch all of the oil vapor. The actual filter I got from McMaster-Carr, item No. 8520T23 for $89.48 You can find it on their website by inputting that number in the search box at http://www.mcmaster.com/#

I'll try to get a photo of my mounting and post it later.

Make no mistake, you should not be breathing that oil vapor, and should by any and all means do something to alleviate the condition. The Robinair is designed to pull hard vacuum on HVAC systems, and thus when you have a constant flow of gas (air) through the pump, as you do when pulling less than 30" of hg. (hard vacuum), the airstream will pick up oil and exhaust it. You've probably noticed the oil condensate on the outside of your motor casing. That's only what isn't atomized into the air.

After I put my filter on, I held a tissue up to the filter's exhaust port and ran the pump wide open to maximize the oil pickup. Tissue was dry and oil free after 2 minutes of continuous running. You will have to empty the filter cup, but you can simply pour it right back into the pump.

Attached are the pix. Tap into the handle with a 1/2" pipe thread then screw in a 1/2" male adapter to which you attached a length of pipe and a union, the other half of which goes to another 1/2" adapter that screws into the filter. You'll need the union to be able to screw everything together but still position your filter in the proper orientation. To take the weight stress off the handle, I made a little wire brace that attached at the back of the handle. You will need some kind of support here. Hope this gives you what you need.

 

[Hugh]

The Gast vacuum pump I have has a small jar on the exhust side and the exhust air goes through the jar and through a small filter. Oil collects in the jar.

Other news - I have been cleaning up my shop trying to get ready for an "Open Studios" thing. Found my pint of oil that I used a few years ago to fill the oiling jar on the vacuum pump. Problem of what oil to use is solved without another purchase, 😀😀

Thanks for the oil advise everyone. I will try to remember where I put the pint of oil for next time (years from now). Good luck with that.

Hugh

 

[bonsaipeter]

Hi Peter,

This will take a bit of plumbing because the exhaust on the Robinair is through the handle. Fortunately, the exhaust "port" is just the right size to carefully tap with a 1/2" pipe tap. Once that is done, a couple of copper fittings and a brace and you can "hang" a coalescing filter off the rear end of the unit that will catch all of the oil vapor. The actual filter I got from McMaster-Carr, item No. 8520T23 for $89.48 You can find it on their website by inputting that number in the search box at http://www.mcmaster.com/#

I'll try to get a photo of my mounting and post it later.

Make no mistake, you should not be breathing that oil vapor, and should by any and all means do something to alleviate the condition. The Robinair is designed to pull hard vacuum on HVAC systems, and thus when you have a constant flow of gas (air) through the pump, as you do when pulling less than 30" of hg. (hard vacuum), the airstream will pick up oil and exhaust it. You've probably noticed the oil condensate on the outside of your motor casing. That's only what isn't atomized into the air.

After I put my filter on, I held a tissue up to the filter's exhaust port and ran the pump wide open to maximize the oil pickup. Tissue was dry and oil free after 2 minutes of continuous running. You will have to empty the filter cup, but you can simply pour it right back into the pump.

Attached are the pix. Tap into the handle with a 1/2" pipe thread then screw in a 1/2" male adapter to which you attached a length of pipe and a union, the other half of which goes to another 1/2" adapter that screws into the filter. You'll need the union to be able to screw everything together but still position your filter in the proper orientation. To take the weight stress off the handle, I made a little wire brace that attached at the back of the handle. You will need some kind of support here. Hope this gives you what you need.

Hi Mark:

Thanks and nicely done. I will have to check it out because I do want to eliminate the oil mist that exhausts from the pump. I have an older Robinair where the handle/exhaut is a simple a piece of 3/8" pipe bent at about an 85 deg. angle, threaded at the short end and screwed into the top of the aluminum pump housing. Mounting the filter may actually be simpler because of the configuration of the handle on my pump.

Thanks again for the information,

Peter Toch

 

[Mark Mandell]

Hi Mark:

Thanks and nicely done. I will have to check it out because I do want to eliminate the oil mist that exhausts from the pump. I have an older Robinair where the handle/exhaut is a simple a piece of 3/8" pipe bent at about an 85 deg. angle, threaded at the short end and screwed into the top of the aluminum pump housing. Mounting the filter may actually be simpler because of the configuration of the handle on my pump.

Thanks again for the information,

Peter Toch

You may have an much easier time than I. With a "pipe" handle, you can replace the plastic grip with some garden hose that extends out in place of all my Rube Goldberg plumbing. Then fit your filter with a 1/2" adapter with a hose bib inserted in the end of your"extension" and you're in business except for a support. You should be able to tie something to the mounting screws on either the capacitor housing, the TEFC shield, or even to the base plate depending on your model.

Good Luck

 

[George Van Beynen]

Not fer nuthin', but my 6 cfm Robinair vac uses straight mineral oil. True, it is designed to pull hard vacuum on HVAC lines, so I had to fit it with a coalescing filter on the exhaust. Pulls 28" on my Stubby's internal port system, and will pull very close to 30" plugged.

FWIF, I don't use any regular oil in any pump situation because of the carbonizing effect. If you can get a synthetic in the right weight, I would use that over others.

Mark, I also have a 6 cfm Robinair and it came with Robinair oil. Is this the same a mineral oil?

 

[Mark Mandell]

Mark, I also have a 6 cfm Robinair and it came with Robinair oil. Is this the same a mineral oil?

Morning George,

That's my understanding from one of the guys I bought the pump from. Robinair does, of course, sell their own branded "Vacuum Pump Oil" so to be sure, I'd suggest that you contact either Robinair or one of their repair/rebuilders like A&A in Ohio (see the first link). It may be mineral oil (which is just super refined dinosaurs, anyway), but they also might put in a necessary additive that the laxative lacks.

http://www.hydraulicparts.com/

PS: Looked up the MSDS for the oil on Robinair's website [ link - http://cache01.voyageurweb.com/otctools.com/newcatalog/products/108692 E.pdf] which sets out various cautions on exposure, but includes a squib about it being a laxative in small quantities. Might be instructive to look up a similar MSDS for the drug store stuff for comparison.

 

[George Van Beynen]

Thanks Mark, I will review your links. I bought mine from Bernie McGivern, I should send him an email also.

BTW, I am waiting for my Kobra, I will let you know when it arrives.😀

 

[Mark Mandell]

Thanks Mark, I will review your links. I bought mine from Bernie McGivern, I should send him an email also.

BTW, I am waiting for my Kobra, I will let you know when it arrives.😀

Bernie (Jr.) isn't there anymore. His brother Dan is running the vacuum/pneumatic side of the shop. Bernie Sr. (the owner) is still there, but Dan's the guy you want to ask.

Excellent choice! Al told me that you'd placed the order. Al and Jerry are very precise in their production, and thus do batch work so they're not continually resetting the machines for the various operations. Takes a bit more time for orders to be filled, but you get a superior product that way.