# How long do you run your vacuum pump for?



## Frank A

When stabilizing in my vacuum pot I was under the impression that people are leaving there pumps on while stabilizing for hours at a time. I've been leaving my pump running so long as I was still seeing bubbles come to the surface.

My pump gets really hot during this time but so far had not had a problem. Should I be doing something different?

What got me thinking about this was my pump has stuck a couple times lately on initially turning it on. Manually rotating the cooling fan on the back gets the shaft turning and it would run from there. I'm not sure if this is a sign its about to die so I'm wondering if there is a preferred pump people here are using?


Thanks,
Frank


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## kweinert

I did this some time back and have been very pleased with it: http://www.veneersupplies.com/products/Project-EVS-Auto-Cycling-Pump-Vacuum-Press-Kit.html - I recall buying most of the pieces locally.

At any rate it's a very good system for holding a vacuum and not requiring your pump to run all the time.

Reactions: Informative 1


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## Sprung

Frank, what pump are you using?

I've had vacuum run anywhere from 8 hours to 48 hours before I've had the bubbles stop. I have this pump. I'm quite happy with it and have had no issues. It does get quite warm while running, but it's ok - and my pump has a thermal shutoff, so if it does ever get too hot, it'll shut itself down.

How often are you changing the oil in your vacuum pump? For the sake of the life of your pump, it should be changed often. I change mine about every 24 hours of run time or every cycle I run if it's longer than 24 hours run time. My father is a refrigeration technician and definitely stressed to me the importance of properly maintaining the vacuum pump, including oil changes - as the oil gets older, it gets contaminated, collects moisture, etc, which will also affect how deep of a vacuum your pump can pull.

If your pump is a kind that can be rebuilt or disassembled, I'd talk to @Schroedc - he's got some experience disassembling and cleaning vacuum pumps.

Reactions: Agree 1


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## Frank A

I'm using the pump that came with my BestValue Vacuum Kit (https://www.bestvaluevacs.com/3cfmpump.html). In terms of the frequency of the oil changes, I was changing it every two to three rounds of stabilization (6 to 12 hours each) so overall it sounds pretty close to your recommendation.


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## Sprung

Those vacuum pumps do not have a good reputation for lasting long, from what I have read. How long have you had yours? It could be that your pump is in the stages of dying. Or it could need a good cleaning inside, if it can be disassembled.

Reactions: Agree 1


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## rocky1

I had the same issues with mine Frank and the problem you're encountering is a build up of crud in the impeller housing. It'll be a brownish, rust looking, nastiness, but really hard. Almost like a mix of rust and poly out of the resin. Mine had one line of it on the inside of the impeller housing, but it's enough to hang the motor up before it gets up to speed

Don't be afraid to take the pump apart, there really isn't anything to it.

Remove bolts around the oil reservoir, remove the reservoir, clean the big wad of nasty goo out of the bottom. Inside you will find a cover with 5-6 bolts that covers the impeller housing. There is nothing in there that's going to jump out and run across the shop and hide from you. Little round plastic impeller, and a reed valve assembly bolted in place on top of the impeller housing. The impeller housing itself is loose and floats around in there, once the bolts are removed. And, that's it for parts!

When you remove the impeller try to wipe the top face dry and mark it somehow, to make sure you get it back in correctly. In the course of cleaning mine up, I got it in upside down, and the impeller wouldn't seat properly when running. Pulled Vacuum, but it quit way short of where it needed to be. There is no right way/wrong way; you can't hurt it if you get it in backwards. The impeller will however have worn slightly through use, and there will be a very slight difference in the angle of the face of the impeller. 

I used steel wool, a utility knife blade, and WD 40 to clean up the inside of the pump. Have no clue what kind of seal it has on the shaft and rather than risk wrecking that with carb cleaner or brake cleaner, it was simply safer to use WD 40 inside the pump. Exercise caution when you attempt to clean the reed valve assembly, the reeds are fairly easy to bend, and they don't work anymore if you bend one. The utility knife blade was necessary to knock to the line of crud loose in the impeller housing. Whatever you use there remember that is where your pump creates vacuum, don't scratch it up, you just want to break the crud loose, not cut into the metal surface.

They can be a tad aggravating trying to get it to work after reassembling, and there is truly no reason for it. They aren't even a little bit complicated; it's such a simple pump that you'll wonder how it works. After flipping the impeller, mine went backwards, could not get it to pull vacuum. After numerous times tearing it down and putting it back together (8 - 10), I finally went around the bolts on the impeller housing cover tightening bolts in very small increments, and that alleviated the problem. There simply wasn't anything there to cause the issues I was having, it acted like the reed valve was not seating the entire time, and I went so far as running it briefly without the oil reservoir on it, to ascertain it was. 

Haven't had any problems out of it since.

Reactions: Thank You! 1


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## rocky1

Back to your original question... My pump gets EXTREMELY HOT too, therefore I don't run it for hours. I have a 5 gallon pot from Best Value that is a beast!! You can pull vacuum on it and it'll hold it for weeks, with no loss, ZERO-ZIP-NADA. So I pull it until the bubbles slow drastically, shut it down, let it sit under vacuum, pull it again, let it sit. Usually after two - three times I'll bleed vacuum off, let it suck up a bunch of resin, then pull it again, and usually that time it'll stop bubbling in 15 - 20 minutes. I'll let it sit awhile and pull it again until it stops bubbling, bleed vacuum off, start over. Usually after 2 - 3 times it'll stop bubbling after just a few minutes. At which point I pull it and put it in my pressure pot and let it sit a day or two at 50 - 90 PSI.

However, if you look at flashpoint on the Vacuum Pump Oil, I think a LOT of them get EXTREMELY HOT. Flash point on most motor oils is around 285o Fahrenheit, transmission/hydraulic oil in my John Deere tractor, the flash point is 285o Fahrenheit, had a buddy send me specs off the oil they use in his commercial refrigeration vacuum pump, flash point was 425o Fahrenheit. So I suspect, hot is a common trait amongst vacuum pumps. I still don't like running mine that hot, so I work around it.


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## JR Custom Calls

Starting one of these pumps under vacuum will cause them to fail prematurely. That is one of the reasons Curtis doesnt build his chambers with a valve on the inlet side.


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## gman2431

JR Custom Calls said:


> Starting one of these pumps under vacuum will cause them to fail prematurely. That is one of the reasons Curtis doesnt build his chambers with a valve on the inlet side.



I always thought it was shutting them off under vacuum that did the damage?


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## JR Custom Calls

gman2431 said:


> I always thought it was shutting them off under vacuum that did the damage?


From what Curtis has said, it's starting them under load that causes issues. Shutting them off under vacuum can suck oil in if they don't have a check valve, which will ruin the resin

Reactions: Informative 1


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## Schroedc

Mine has run as long as 20 hours (JB Eliminator pump) I start it with no load and close a valve, have a valve on the other side to close off so the chamber hold vacuum, then release vac at the pump and then shut it off. I also change the oil fairly quick after that while still hot so the water and oil run out easy. (When I stabilize I run multiple loads in a row so at the end of that I'm due to change oil anyways)


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## norman vandyke

I've had two pumps burn out on me that did the same thing. Mine eventually got so hot that they seized, overheated to the point of melting the wires and shorted out the pump.


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## Jim Beam

What are you guys using for vacuum pump oil? I've been using ATF but I'm a little worried that it might bot be the best choice.

That said, I scored a 6 CFM JB Eliminator for $90 on FleaBay

Reactions: Way Cool 1


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## norman vandyke

I've been using robinair vacuum pump oil. Lol


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## JR Custom Calls

Jim Beam said:


> What are you guys using for vacuum pump oil? I've been using ATF but I'm a little worried that it might bot be the best choice.
> 
> That said, I scored a 6 CFM JB Eliminator for $90 on FleaBay


I used ATF without issue. Aside from the whole 'probably not the best choice for air quality', it seemed to do the job just fine. And it was a heck of a lot cheaper than vac pump oil.


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## Frank A

I've always used Robinair aside from what they shipped with my pump originally.

Reactions: Agree 1


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## rocky1

First... Yes, I am aware starting under load is supposed to cause premature failure Jonathon. That being said, from a design standpoint the only thing that could possibly fail prematurely is the impeller, which is maybe a $5 part, if you can find it. 

Second... The pump I have, and probably the pump several of you guys have, isn't designed for the resins we're using, and the manufacturer of my pump states, that the fumes off wood stabilizing resins will cause premature failure of the pump, let alone the occasional drop or two of resin that gets sucked back up the tube into the pump. And, they want to sell me a $400 filtering system to filter out the fumes, to save a $90 pump. 

 I'm thinking I'll just run the SOB until it blows up, and buy another one, 3 more times, and have half enough left over to buy a fifth pump for the cost of their filter. HELLO!! 

And, finally... Since the impeller is a high density plastic of some nature, yes it can no doubt be affected by the resins we use. Such exposure would likely tend to make it hard and brittle. Being a plastic, it would also be affected by long term exposure to high temperatures, that would likely tend to make it hard and brittle too. Wherein combining the two on a daily basis and starting it under load, might cause the impeller to prematurely fail. 

Did any of you guys pumps come with a statement of "Life Expectancy" so we know if they failed prematurely? 


Last couple oil changes I used John Deere Hy-Gard. Buck or two a quart cheaper than vacuum pump oil. It's designed for transmission/hydraulic use on half million dollar combines and tractors, I'm pretty sure it'll stand up to a $90 vacuum pump. Until it gets a good bit of moisture in the oil, as in beyond needing changing, it runs about 30o - 40o cooler than it did with new Vacuum Pump Oil in it. No ill effects seen otherwise. And it, like ATF should have conditioners to keep seals and o-rings, and plastic parts from getting hard and brittle prematurely.


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## blaineo

Oil change is probably the most important thing you can do. It will generate condensation usually and the water will collect in the BOTTOM of your reservoir, which you CAN'T SEE in your sight glass. And the water is the first thing it will pull into the pump when you turn it on. If it's pumping water, it will shut down or seize up. Change that oil regularly and be mindful...:)

Reactions: Thank You! 1


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