Robinair(15500) VacuMaster Economy Vacuum Pump - 2-Stage, 5 CFM , Red

I committed the typical amateurish error of trying out cheaper two-stage vacuum pumps...with predictable results. They either didn't perform as advertised right out of the box, or they failed within several uses - even with proper maintenance.This thing, however, delivers on the promise.I filled it with the included oil. First time powering it up, it pulled the rated vacuum quickly when dead-headed.That first charge of oil became cloudy after just a few uses, so I drained it and replaced it with fresh Robinair vacuum oil. At that point, the ultimate vacuum plunged to 9 microns. (I suspect that the first charge of oil took the brunt of the break-in, and that's why it clouded up so quickly. But that's something to be aware of if you buy this pump. Keep a close eye on the clarity of the first oil charge, as it will probably cloud up pretty quickly.)Since then, this pump has been worked very hard. It has been operated for hours on end with no loss of performance whatsoever. Since my application doesn't expose the oil to excessive moisture, the oil has remained clear after the equivalent of days of operation.There is oil fog released when the pump is operated under no load, or when it is under load but evacuating at a high flow rate. It's inevitable and is present with all pumps of this type.There are aftermarket oil mist separators available that can mitigate the oil mist, but they're expensive. Just expect the oil mist, and make sure you have adequate ventilation wherever the pump is operating.

Fantastic performance for the intelligent DIY'er that is not thinking of only one case but can see ahead to multiple usage cases. I can say for sure I bought mine and I have used it like 10 times since and about to use it again. I can say for sure that IF you want some thing with performance to match the vacuum levels professionals need, but don't need to the time performance a contractor needs. And this is the key! YOU need some thing that can pull a low enough vacuum. A lot of the single stage units that cost less cannot. So, it is really a question of WHICH 2 stage vacuum pump will work for you..

Very high quality pump. I've owned others and not only could I tell an immediate difference in build quality by how heavy and well put together this pump is compared to the others but the quietness and deep vacuum ability are unparalleled. I live in the NE heights of Albuquerque so my elevation is around 5400ft (1645 meters) above sea level. Most people forget to calculate elevation into the amount of mercury your able to pull but I'm here to tell you it factors a GREAT DEAL INTO IT. For instance at my elevation I'm only supposed to be able to pull 25inHg with a vacuum pump that pulls 29-30inHg at sea level (San Diego, CA for instance). So if your at a high elevation like me(Denver for instance) and can't understand why your vacuum pump rated for 29inHg is only pulling 25, it's not the pumps fault (more then likely). Bc the higher your elevation the lower the available atmospheric pressure. Why the meteorology lesson you say?! I'll get to the point. Even tho this pump is technically only able to produce 25inHg at 5400ft it was consistently producing beyond that teetering between 27-28inHg which along with the build quality and quietness of the pump should make you not even consider the cheaper pumps (which I wasn't able to get more then 25inHg from) and spend the little extra money on this. I've had for about a month and a half at this point and used it to pull vacuum on 3 different vehicles (one of which I've pulled a few times bc of how old and long it was open to the elements) and the oil is still really clean. I did just get my replacement robinair oil tho- 2 quarts~$20 on Amazon so I'll be replacing it before the next run-also bc it is a tad low.I'll update review as it gets older if I have any issues but based on build quality and the maintenance I'll give it- I don't suspect I'll have any. Sorry for the winded review! Hopefully it helps someone!

This is a good pump and can very quickly (less than 60 seconds for 3 gallons) achieve 29" Hg. That is all it can achieve however. I believe it has no problem hitting 5CFM. It's the ultimate vacuum rating of 35 microns (which, by the way, is like 99.999% of full vacuum or 29.9163" Hg something or other) that it never hits. It was able to hold a solid 29" of Hg but never below it. That's like 20,000 microns or something. Big difference between 35 microns and 20,000 microns! That's my only beef with it. Wish it woulda performed as I'd hoped cause it was a great price. Guess I shoulda known it was too good to be true. Amazon had no problem letting me exchange it for a pump with performance characteristics that I needed. That's my two cents.